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United States
Department of Agriculture
Forest Service
Southwestern Region
Submitted by:/s/ Gayle Richardson Forester-District Silviculturist Apache-Sitgreaves National Forests
Vegetation Management Specialist Report Larson Forest Restoration Project
Larson Forest Restoration Project Silviculture Specialist Report
July 30, 2014 Page 2 of 67
Introduction
Silviculture is the art and science of controlling the establishment, growth, composition,
health, and quality of forests and woodlands to meet diverse needs and values of landowners
and society on a sustainable basis (SAF 1998). This specialist report describes the current
and desired vegetative characteristics of the project area. Acres of forestland and cover types
meeting definitions for Mexican spotted owl (MSO) and northern goshawk (NOGO) habitats
are described and summarized.
The Forest Service defines ecological restoration as the process of assisting the recovery of
resilience and adaptive capacity of ecosystems that have been degraded, damaged, or
destroyed. Restoration focuses on establishing the composition, structure, pattern, and
ecological processes necessary to make terrestrial and aquatic ecosystems sustainable,
resilient, and healthy under current and future conditions (USDA 2010).
Desired conditions are often described in terms of composition (species mix), structure (size,
density, and vertical or horizontal arrangement), and function (interaction with other
physical, chemical, and biological elements of the forest environment). Composition,
structure, and function bear directly on forest values, whether timber production, wildlife
habitat, recreational opportunity, aesthetics, livestock grazing, soil and watershed condition,
or fire regime.
Forest vegetation composition, density, structure, and diseases such as dwarf mistletoe are
the primary forest conditions which can be affected by silvicultural treatments. Stand
composition can be altered with silvicultural treatments by manipulating a stand to create
early seral1 stage conditions. The remainder of this report examines these conditions in the
context of the Larson Forest Restoration Project. The project was developed in consideration
of the best available science.
Area of Analysis
The area analyzed is forestlands, meadows, and riparian areas of the Apache-Sitgreaves
National Forests within the boundary of the Larson Project, totaling approximately 30,041
acres. There are two inclusions of private land which are not part of the proposed action and
therefore not analyzed in detail. The area ranges in elevation from 6,900 to 7,600 feet.
1Seral – a temporal or intermediate stage in the process of succession (SAF 1998)
Larson Forest Restoration Project Silviculture Specialist Report
July 30, 2014 Page 3 of 67
Relevant Laws, Regulation, and Policy that Apply
Multiple-Use Sustained Yield Act of 1960. Requires that national forest lands shall be
administered for a variety of multiple uses, and that all resources shall be maintained as
renewable in perpetuity for regular periodic output of several products and services at a
sustainable level.
National Environmental Policy Act of 1969 (NEPA). Established procedures for
decision making, disclosure of effects, and public involvement on all major federal actions.
National Forest Management Act of 1976 (NFMA). The A-S forest plan was
developed in accordance with NFMA, as expressed by the 1982 planning rule.
While federal laws like the National Forest Management Act establish the regulatory
requirements of forest management for federal agencies, the detailed direction that affects the
project-level vegetation analysis being undertaken in this proposed action are contained in
the forest plan for the Apache-Sitgreaves National Forests (USDA 1987, as amended 2009).
These include the goals, objectives, direction, and Forest-wide and Management Area
standards and guidelines referenced below that have relevance to the proposed action:
Management direction for riparian and timber related activities including integrating
considerations for economics, water quality, soils, wildlife habitat, recreation
opportunities, visual, and other values in project design.
Standard Management Treatment Table –Standard Vegetative Management Practices
for Certain Composition, Structure, and Function Attributes (to be used at the
stand/site level).
Vegetation Management Practices for ponderosa pine, mixed conifer, and aspen
vegetation types as it applies to uneven-aged harvest systems2, pre-commercial
thinning, intermediate thinning, and prescribed burning (table 13).
Standards and guidelines for Threatened, Endangered, and Sensitive Species.
Forest-wide standards and guidelines including objectives to make miscellaneous
forest products and fuelwood available in timber management activities.
Management Area 1 - Forested Land - Management emphasis is a combination of
multiple uses including sustained yield of timber and firewood production, wildlife
habitat, livestock grazing, watershed, and dispersed recreation.
Management Area 16 - Chevelon Canyon – Strive to maintain current opportunities
for solitude. Protect the high scenic values, and maintain current wildlife habitat
values.
Forest vegetation management direction in the Apache-Sitgreaves National Forests Land
Management Plan (USDA 1987, as amended 2009) was amended in 1996 through a region-
wide amendment of all forest plans in Arizona and New Mexico (USDA 1996). The Larson
project is designed with two site-specific, project-specific non-significant forest plan
2 uneven-aged harvest systems– a treatment designed to maintain and regenerate a stand with three or more age
classes (SAF 1998).
Larson Forest Restoration Project Silviculture Specialist Report
July 30, 2014 Page 4 of 67
amendments that only apply to the Larson Forest Restoration Project and can be found in the
issues and alternatives letter dated February 28, 2014.
Methodology Used for Data Collection and Analysis
Common Stand Exam (CSE) (USDA 2008b) data collected over the last 26 years within the
project area and a portion outside of the project area, with similar forest types, were used in
determining the information in the tables below (appendix A). Forested and non-forested
areas were delineated based on similar tree characteristics into stands. Stands vary in size,
depending upon their uniformity, usually 10 acres in size up to several hundred acres. Tree
characteristics were measured at sample points within each stand, using both variable basal
area factor plot and fixed plot designs and data entered into the Field Sampled Vegetation
(FSVeg) database (a standard national database used to store field sampled data in a common
format Forest Service wide). These attributes include but are not limited to forest type, tree
species and size, and insect and disease damage, for each sampled stand.
Approximately 46% of the forested project area has current stand exam data. The remaining
area either had no data collected, or the data was no longer valid due wildfires or recent
vegetation treatments.
A computer modeling program called Most Similar Neighbor (MSN) was used to assign
stand characteristics to the stands with no field collected data, for the purpose of this analysis
(Crookston et al. 2002). MSN analysis uses satellite imagery, spatial relationships, and
topographic information to match target stands without data to the nearest reference stand
with data. Tree data from the reference stand is then assigned to the target stand without
data. Table 1 displays the approximate acres with adequate data sampled or reference data
and the number of acres using MSN including stands inside and outside the Larson project
boundary.
Table 1. Summary of acres with valid stand exam data and MSN data.
Data
Sampled
Grassland/
meadows
Private/
Reservoirs
Good
Quality
Poor
Quality
Current
Data Total Acres
MSN* 17,075 364 14,439
Stand Exam Data 12,463 12,463
No data required 171 120 291
*MSN – acres without current data.
A combination of field reconnaissance, GIS analysis and review of stand data was used to
determine treatment needs, logging feasibility, and stand health.
All of the stand data was compiled into a database and modeled in the Forest Vegetation
Simulator (FVS) tree growth model within the FSVeg Spatial Data Analyzer (DA) program.
The FVS is a model used for predicting forest stand dynamics that is used extensively in the
United States and is the standard model used by various government agencies including the
USDA Forest Service, USDI Bureau of Land Management, and USDI Bureau of Indian
Affairs (Dixon 2008). The Central Rockies variant of the model was used for this project’s
Larson Forest Restoration Project Silviculture Specialist Report
July 30, 2014 Page 5 of 67
geographic area. Forest managers have used FVS extensively to summarize current stand
conditions, predict future stand conditions under various management alternatives, and
update inventory statistics. It models tree growth, natural occurrences, and management
actions. The model is a density-dependent model which limits the ability to model openings
created for uneven-aged management using group selection.
The FVS was used to simulate growth to a common year of 2015 and cutting and prescribed
burning treatments and growth following treatments for each alternative up to the year 2045.
The FSVeg Spatial DA allows the user to understand the data through use of the FVS growth
simulator and landscape vegetation analysis as related to vegetation change based on natural
change over time and due to vegetation management activities (USDA 2014).
For simulation purposes, each data set was grouped by current forest type, wildlife habitat
(MSO or NOGO), site class and treatment type. Simulations were developed for each
treatment based on desired conditions. A multitude of vegetation and fuels attributes were
computed for each growth cycle. Attributes include tree density (trees per acre (TPA), square
feet of basal area (BA) and stand density index (SDI)) by species or species groups and
vegetative structural stage (VSS) size class, dwarf mistletoe infection, stand density index,
cubic feet of biomass removed, canopy base height and bulk density, live and dead surface
fuel loading, live and dead standing wood, coarse woody debris, snags, and Fire Regime
Condition Class (FRCC). These attributes were then averaged for all the data sets
represented in the simulation. The averaged computed attributes from FVS were also used to
calculate other attributes such as dominate VSS size class, canopy density and even-aged or
uneven-aged structure. All of these attributes were then compiled into an “effects” database
by alternative and used to analyze and display the direct and indirect effects to the vegetation
resource.
The following is a list of general modeling assumptions.
All tree data was grown to the common year of 2015 and is considered to represent the
existing condition.
All tree cutting and removal was modeled in the year 2015.
All shelterwood with reserves was modeled in 2015 and in 2025.
Two prescribed burns were modeled, the first in the year 2020 and the second in 2030.
Assumptions that interspace would be maintained across the landscape and carried
through to 2035.
After treatment, the tree data was grown to the common year of 2020, 2025, 2035, and
2045 and is considered to represent the post treatment condition.
The tree data does not indicate tree age. Simulations use diameter as a surrogate for age
based on the vegetative structural stage definitions. We acknowledge that there are trees
on the landscape where age class overlaps size class. For example there may be: young
trees that are larger than 11.9”; or mid-aged trees that are larger than 17.9”; or mature
trees that are less than 18”.
Larson Forest Restoration Project Silviculture Specialist Report
July 30, 2014 Page 6 of 67
The modeling assumptions attempted to meet the spirit of the Large Tree Retention
Strategy within the limitations of a non-spatially explicit model for alternative 3.
Green biomass resulting from the cutting is assumed to be removed.
Default parameters within the model were used to predict tree growth, mortality, and
dwarf mistletoe infection intensification.
Snags and coarse wood amounts are based on the inventory or default parameters within
the model if they were not inventoried. Snag fall rates and changes in surface fuels are
based on default parameters.
Modeling was based on the prescriptions found in appendix B.
Modeling favored the VSS3 class for removal first because they were in excess and
regeneration openings should be able to be created in both alternatives 2 and 3.
Limitations
Stand exam data is an average characterization of the area within the stand boundaries. It is
limited by sampling intensity and the variability within the sampled area.
Dwarf mistletoe infections are difficult to detect from satellite imagery. Therefore, the MSN
imputation process may have imputed stand data showing mistletoe infections to stands that
are not infected and visa-versa.
FVS is not spatially explicit and cannot model tree groups and interspaces3. The modeling
was designed to mimic groups and interspaces but is an average approximation of the desired
forest structure.
Results from the FVS model depend upon sample data, validity of the model itself and
assumptions made by the modeler. Output from the FVS model used in this analysis is a
characterization of the existing condition and relative change over time of management
actions or no action. Absolute conditions are neither intended nor implied.
Modeling was based on 30 year cutting cycles for unevenaged management thus removing
some trees which may physically be left in the implementation process.
Pre-settlement trees cannot be identified through the modeling program, only in the field
through individual marking.
Historical Data
The Ecological Restoration Institute (ERI) gathered site-specific historical ecological data to
establish reference conditions for the project area (Sensibaugh et al. 2013). Historic and
current tree data was collected on 66 plots across the project area. Photos were also taken at
each point and are included in appendix E. Information collected by ERI in the Rim Lakes
Forest Restoration Project was also used to determine pre-settlement fire frequency, severity,
3 Interspace is defined as the grass-forb-shrub openings between groups of trees (USDA 2013).
Larson Forest Restoration Project Silviculture Specialist Report
July 30, 2014 Page 7 of 67
and spatial patterns as well as tree density, species composition, and size distribution
(Sensibaugh et al. 2013).
Stratification
All forested habitat was stratified to meet analysis requirements in the forest plan for
Mexican spotted owl (MSO) and northern goshawk (NOGO) as displayed in figure 1.
Figure 1. Stratification of forested and non-forested land.
*Non-forested lands include meadows, wetlands, private land, reservoirs, powerlines, and
gravel pits not included in MSO or NOGO habitat. Small inclusions of non-forested may
occur in forested lands due to designations within MSO protected habitat and NOGO post
fledgling area (PFA) habitat.
Affected Environment
The current condition was shaped by natural processes and past human activities. Significant
human activity was first recorded as occurring during the 1880s, when livestock (cattle,
sheep, and horses) were introduced to the Mogollon Rim region by travelers and settlers.
Unregulated grazing greatly impacted grass/forb/shrub forest understories, in many cases so
severely that naturally-occurring frequent fire activity was ceased (Sensibaugh et al. 2013).
In some locations no fire has occurred since the 1880s time period. This has resulted in
Larson Forest
Health Project
30,041 acres
Forested Lands
29,514 acres
Non-Forested
Lands*
527 acres
Northern
Goshawk
Habitat
(NOGO)
26,665 acres
Mexican Spotted
Owl (MSO) Habitat
2,849 acres
Larson Forest Restoration Project Silviculture Specialist Report
July 30, 2014 Page 8 of 67
regeneration and development of uncharacteristic forest tree densities and downed woody
fuels, posing a high risk of uncharacteristically severe fire effects.
The first timber harvest entries in the area occurred in the 1940s. These actions focused on
removal of large dying trees and high-grade lumber. From the 1950s-1970s, management
focused on sanitation or salvage of imminent tree mortality and diseased or damaged trees.
Minimal forest density management occurred during this period. In the 1960s, the practice of
cutting snags to reduce fire hazard also reduced the number of snags currently standing but
may have increased the number of logs present in some areas.
Starting around 1980, management was focused on even-aged forest management strategies,
such as the shelterwood silviculture system. Treatments were conducted on selected stands
and large blocks throughout the project. Individual stand treatments focused on overstory
removals of mature trees where a younger age class was present.
Where mature trees dominated, regeneration treatments, focused on removal of most
overstory trees and retention of scattered low-density seed trees. Where sapling or mid-aged
trees dominated, treatments focused on thinning to manage stand density. Much of the
thinning treatments yielded pulpwood products, and the removal and regeneration treatments
yielded sawtimber.
Past timber sales in and near the project, such as Larson Multiproduct Sale, St. Joe Timber
Sale, Smith-Paradise Timber Sale, and others, all implemented prior to the 1996 Forest Plan
amendment, targeted the harvest of medium and large diameter trees. In some cases, all trees
over 16 inches in diameter were removed. Trees between 5 to 12 inches diameter at breast
height (dbh) were not removed or thinned after the timber sale. Limited thinning of trees up
to 5 inches dbh occurred only within the timber sale cutting units. This created
uncharacteristic forest stand conditions that currently exist across most of the Larson project
area. This even-aged forest management focus continued until the mid-1990s, leaving the
legacy of current forest conditions. All of the areas where regeneration treatments were
conducted have adequately regenerated. Many stands are currently single or two-aged, with
homogenous forest canopy structures and high density.
During the recent past (mid 1990s - present), selected small areas were thinned to reduce fire
hazards adjacent to public areas such as the community of Forest Lakes and Canyon Point
Campground. These thinning treatments focused on removal of trees less than 16 inches in
diameter, producing results similar to the mid-aged stand thinning treatments conducted
during the 1980s period.
Several large-scale fires have occurred adjacent to the project area. The Rodeo-Chediski Fire
borders Larson on the south side and the Chevelon Complex (Weimer, Durfee, and Wagon
Draw Fires) borders the project area on the north side.
Future projects include the Rim Lakes Forest Restoration Project adjacent to the project area
which focuses on removal of trees less than 16 inches. Additional projects are listed in the
table 26.
Larson Forest Restoration Project Silviculture Specialist Report
July 30, 2014 Page 9 of 67
Vegetative Cover Types
Forest stands are often classified by their forest type and by habitat type or plant associations.
This analysis will focus on forest cover types identified in the forest plan (USDA 1987, as
amended 2009) for MSO and NOGO habitat. Table 2 displays the acres of forested and non-
forested land within the project area. Stratification of the forested cover types and acres by
habitat and forest type is displayed in figures 2 and 3.
Table 2. Forested and Non-forested acres based on
stratification.
Stratum Cover Type Acres
Forested
Ponderosa pine 27,754
Mixed Conifer 1,676
Aspen 63
Total Forested 29,493
Non-Forested
Private Land 120
Grassland 419
Gravel Pit 9
Total Non-Forested 548
Total Project Acres 30,041
Existing Condition
Non-Forest Vegetative Cover Types
Dry meadows and grasslands are present in the analysis area. The powerlines are maintained
on a 5 year basis as grassland, and therefore were classified as grassland rather than forested
because they are excluded from goshawk management. Two gravel pits fall within the area
with ponderosa pines encroaching into them.
Forest Plant Community Types
Habitat types are an aggregation of units of land capable of producing similar plant
communities at climax (SAF 1998). Each habitat type is usually named for the most shade-
tolerant species regenerating successfully and usually considered the climax or later
successional species in the absence of disturbances such as fire. The majority of the project
area is a ponderosa pine habitat type with the remaining stands identified as Douglas-fir
habitat types. Aspen, Gambel oak, box elder, narrowleaf cottonwood, and New Mexican
locust can be found scattered throughout the project as inclusions in the ponderosa pine and
mixed conifer forest types.
Larson Forest Restoration Project Silviculture Specialist Report
July 30, 2014 Page 10 of 67
Mex
ican
Sp
ott
ed O
wl
(MS
O)
Hab
itat
(acr
es)
Protected
Activity
Center (PAC)
(acres)
Pine-Oak (acres) 1
265
Mixed Conifer
(acres) 1
640
Ponderosa Pine &
Other (acres) 1
1630 725
Rec
overy
Hab
itat
(acre
s)
Pine-Oak (acres)
Recovery Nest/Roost (Min of
10% of acres) 1
149
Recovery Foraging (Max 90% of
acres) 2, 3
184 35
Mixed Conifer
(acres)
Recovery Nest/Roost (Min. 25%
acres) 1
415
Recovery Foraging (Max 75% of
MC acres) 2, 3
2,850 1,220 1,036 621
1 100% of the area would be allocated to be managed for old growth structure.
2 MC recovery allocation varies by ecosystem management unit (2012 MSO Recovery Plan).
3 Uneven-aged forest would be managed towards allocation of 40% of the area to mature structural
stages. Mature even-aged forest structure would be managed towards uneven-aged forest conditions, by group selection cutting methods (80% would be managed for old growth).
Figure 2. Mexican spotted owl (MSO) habitat stratification and acres.
Larson Forest Restoration Project Silviculture Specialist Report
July 30, 2014 Page 11 of 67
Northern
Goshawk
Habitat
(Ponderosa
pine forest)
Nest Habitat 216 acres
Post Family Fledging
Areas (PFA) Habitat
751 acres
Uneven-aged
416 acres
Even-aged
335 acres
Areas Outside of PFAs
(acres)
Uneven-aged
17,060 acres
Even-aged
(Foraging)
8,766 acres
26,793 acres 25,826 acres Uneven-aged forest would be managed towards allocation of 40% of the area to mature structural
stages. Mature even-aged forest structure would be managed towards uneven-aged forest
conditions, by group selection cutting methods (80% would be managed for old growth).Uneven-
aged stands would be managed towards 40% large tree structure.
Figure 3. Northern goshawk (NOGO) habitat stratification and acres.
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July 30, 2014 Page 12 of 67
Ponderosa Pine and Pine-oak
Ponderosa pine commonly grows in pure stands and currently is found in even-aged4 and
uneven-aged5 structural conditions across the area (figure 3). A portion of the stands have a
large enough component of Gambel oak to be considered pine-oak habitat for MSO (as
described in the forest plan and MSO Recovery Plan). Ponderosa pine also occurs as an early
successional or seral species in mixed conifer stands, where it gives way to more shade-
tolerant species such Douglas-fir and white fir as succession progresses. Limited remnant
patches of aspen can be found throughout the southern portion of the project within the pine
stands. An alligator juniper component with large junipers and dense juniper regeneration
occurs on the drier sites in the northern portion of the project and accounts for approximately
30% of the ponderosa pine acres.
Mixed Conifer
Mixed conifer is composed of ponderosa pine, Douglas-fir, white fir, southwestern white
pine, and Gambel oak. The majority of mixed conifer found in the project area is dominated
by ponderosa pine and Douglas-fir, and is considered to be a dry (historic frequent-fire)
mixed conifer forest type (Sensibaugh et al. 2013). Portions of the mixed conifer type are in
mid-succession or climax condition with an understory of white fir. The cessation of frequent
fire has resulted in increasing regeneration of shade-tolerant white fir. Over time, species
composition will shift from fire-resistant shade-intolerant species to non-fire-resistant shade-
tolerant species dominance. Some stands within the project have currently transitioned to
dominance of shade-tolerant species. Ponderosa pine and southwestern white pine are
regenerating where old logging roads and scattered openings occur in the stands.
Aspen
Aspen exists within the southern half of the project area in small isolated patches or within
portions of the canyons. These patches typically consist of a few overstory trees with a
sapling component of 3 to 8 inch diameter trees. Elk are particularly damaging to aspen,
browsing on aspen suckers, rubbing antlers on mid-sized trees and eating bark from larger
trees. Several aspen patches or clones show signs of decline marked by mortality and
dieback of crowns, similar to what has been observed across Arizona over the past several
years (Fairweather 2008). Aspen are regenerating successfully where fencing has been
maintained to exclude wildlife or on the steep canyon slopes. Approximately 30 acres were
fenced and treated under the Larson Multi-product Sale in the 1990’s for aspen regeneration
but several are in need of repair and ineffective. Mature aspen in the project area are dying
due to defoliation by various insects and disease agents, or age-related senescence
(Fairweather 2008).
4 Even-aged – pertaining to a stand composed of a single age class in which the tree ages are within + 20
percent variability based upon the mature stand age (SAF 1998). 5 Uneven-aged – pertaining to a stand with trees of three or more distinct age classes (SAF 1998).
Larson Forest Restoration Project Silviculture Specialist Report
July 30, 2014 Page 13 of 67
Forest Health
For the purposes of this analysis, forest health is defined by the vigor and condition of the
forest stands, and the presence of insects and disease that affect the sustainability of the
forest. A working definition of a healthy forest is a forest where:
1) Stand densities are at levels that facilitate overall forest development, tree vigor, and
resilience to characteristic disturbances, and;
2) Native insect and disease activity is within the historic range of variability, and non-native
insects/diseases are absent or incidental and;
3) Forest structure represents all age classes necessary for a sustainable balance of
regeneration, growth, mortality and decomposition, and;
4) Overall these conditions are resilient to natural biotic and abiotic disturbances (e.g.,
insects, diseases, fire, and wind).
Stand Density
Stand density is the dominant factor affecting the health and vigor of the forest (SAF 2005).
Long (1985) divided Stand Density Index (SDI)6 percentages into four zones which consider
the percent of a stand’s overall density relative to the biological maximum density (species-
specific measure). Table 3 displays the dynamics of regeneration establishment, tree
competition and growth based on stand density percentages (species-specific percent of
maximum stand density index). Based upon established forest density/vigor relationships,
density-related mortality begins to occur once the forest reaches 45-50% of maximum stand
density (zone 3), and mortality is likely at density levels of 60%+ of maximum stand density
(zone 4). Stand density and several related topics are discussed in more detail in appendix C.
6 Measure of stand density in relationship to number of trees in a stand to quadratic mean diameter expressed as
a percentage of the maximum (SAF 1998).
Larson Forest Restoration Project Silviculture Specialist Report
July 30, 2014 Page 14 of 67
Table 3. Relationship of percent of maximum SDI and Langsaeter's zones to stand and tree
characteristics (Long 1985). (Relationships of forest density to stand and tree characteristics).
% Maximum
SDI*
Zone Stand and Tree Characteristics
0 – 24%
Low density
1
Less than full site occupancy, maximum understory forage production.
No competition between trees, little crown differentiation.
Maximum individual tree diameter and volume growth.
Minimum whole stand volume growth.
For mixed-conifer forest types:
Regeneration of shade intolerant tree species favored (early seral
species - Ponderosa pine, aspen**)
25-34%
Moderate
density
2
Less than full site occupancy, intermediate forage production.
Onset of competition among trees, onset of crown differentiation.
Intermediate individual tree diameter and volume growth.
Intermediate whole stand volume growth.
For mixed-conifer forest types:
Regeneration of shade intolerant tree species favored (Ponderosa pine,
aspen). Conditions becoming suitable for more shade tolerant species
(early-mid seral species- Douglas fir, white pine**)
35-60%
High density
3
Full site occupancy, minimum forage production.
Active competition among trees, active crown differentiation.
Declining individual tree diameter and volume growth.
Maximum whole stand volume growth.
Upper range of zone marks the threshold for the onset of density-
related mortality.
For mixed-conifer forest types:
Regeneration of shade tolerant tree species favored (mid-late seral
species - true firs, spruce species**)
>60%
Extremely high
density
4
Full site occupancy, minimum forage production.
Severe competition among trees, active competition-induced
mortality.
Minimum individual tree diameter and volume growth, stagnation.
Declining whole stand volume growth due to mortality
For mixed-conifer forest types:
Shade tolerant tree species favored (late seral species - true firs, spruce
species **)
Percentages based upon individual species (Shaw and Long 2011)
* Ponderosa pine SDImax basis (450), Douglas-fir SDImax basis (570)
**Represents typical species successfully reproducing in the understory, other species may
regenerate but are not likely to be competitive with the typical species at the specified density
level.
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Table 4 portrays the existing percent maximum SDI and basal area (BA)7 for the forested
area within the project area. The lower stand densities are concentrated in areas of recent
timber sales on the south side of the project area. Based on the averages, 99% of the forested
area is considered high density (Zone 3) and 1% falls in extremely high density (Zone 4) as
shown in figure 4. Figure 5 represents the low to moderate, zones 1 and 2, and the historic
condition.
The Larson project area is beginning to see declining tree growth and minimal forage
production because the majority of stands in the Larson project area in zones 3 and 4. Severe
competition for light, water, and nutrients is occurring as seen in Figure 4. Larger trees are
dying from individual bark beetle attacks and understory competition. The majority of stands
have not had any thinning occur in the 5 inch to 12 inch size classes leaving them extremely
dense with interlocking canopies. Goshawk foraging habitat represents 87% of the forested
project area and of these acres approximately 70% is in zones 3 and 4.
Figure 4. High stand density within the project area (Sensibaugh etal. 2013).
7 Basal area (BA) – the cross-sectional area of a single tree stem, including bark, measured at breast height in
square feet (SAF 1998).
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Figure 5. Low to Moderate Stand Density (Uneven-aged Management Strategy)
representing the historic condition (Sensibaugh et al 2013).
Insects and Diseases
The annual insect and disease aerial surveys on the Apache-Sitgreaves National Forests
(USDA 2008a) conducted in the late summer show a continuation of bark beetle-related
mortality in the mixed conifer. Bark beetle activity in Douglas-fir (Douglas-fir beetle) and
white fir (fir engraver beetle) has been increasing over the past few years the Black Mesa
Ranger District, especially in the canyons (Fairweather 2008).
Past seasons of drought and overly dense forests are the primary triggers of the epidemic that
recently occurred in the Southwest (USDA 2008a). An outbreak of bark beetles, starting in
2002 to 2003, resulted in widespread mortality across Arizona, including mortality within the
project. The outbreak was primarily the result of several native bark beetle species
responding to the weakened condition of moisture-stressed, over-crowded forests. Trees in
stress-prone stands were most affected (Fairweather 2008). A decrease in affected acres
began to occur in 2007 (USDA 2008a). Bark beetle activity in ponderosa pine currently
appears to be at endemic levels.
Larson Forest Restoration Project Silviculture Specialist Report
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Table 4. Existing (2015) and desired forest density .
Habitat Existing
Acres**
Existing
Condition
BA
Average**
Existing
Condition
BA
Ranges**
Desired
Condition
BA***
Existing
Condition
Average
SDI% of
Maximum
Desired
Condition
***
SDI% of
Maximum
Mexican Spotted Owl
Protected Core 136 175 120-198 N/A 54% (3) N/A
Protected
Outside Core 1,493 140 3-264 N/A 46% (3) N/A
Recovery
Foraging 656 164 74-198 70-90* 52% (3) 25-40%
Recovery
Nest/Roost 564 154 74-198 110-120* 49% (3) N/A
Goshawk
Nest 216 175 111-230 80-100 63% (4) 35-45%
PFA 751 157 73-228 70-80* 58% (4) 25-40%
Foraging 25,698 148 29-247 50-70* 51% (3) 15-35%
* Within stand matrix (not including regeneration group openings).
** Not all acres are proposed for treatment. Existing density statistics reflect regenerating and other young
stands that are not proposed for treatments.
*** Appendix C describes stand density index calculations and the basis for desired density conditions related
to the forest plan vegetation standards and guidelines and project purpose and need. The desired condition
density ranges represent the zone where attainment of both forest health objectives and uneven-aged forest
development/maintenance objectives are biologically feasible.
Bark beetle hazard is high over the analysis area. In general, ponderosa pine stands that have
an average diameter greater than 12 inches are hazard-rated based upon stand BA: BA
greater than 120 ft2/acre are considered at high hazard to bark beetle attack; BA of 80 – 120
ft2/acre are considered moderate hazard; and BA less than 80 ft
2/acre are considered low
hazard (McMillin 2004).
Dwarf mistletoe infection in ponderosa pine and Douglas-fir is common throughout the area.
Dwarf mistletoes continue to have a major impact on growth and mortality of conifers8 in the
Southwest (USDA 2008a). The incidence of dwarf mistletoe is quantified during stand
exams. Approximately 87% of the acres with current stand exam within the project area
have some level of infection (table 5). Southwestern dwarf mistletoe was observed in
8 Conifers – cone bearing trees which are found within the project area including: ponderosa pine, Douglas-fir,
white fir, , Southwestern white pine, rocky mountain juniper, alligator juniper, pinyon pine, one-seed juniper.
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ponderosa pine and Douglas-fir dwarf mistletoe in the Douglas-fir. Table 5 displays the
stand rating by infection severity class.
Table 5. Acreage percentages of existing and desired stand level dwarf mistletoe infection
by severity class within the Larson project area (Hawksworth and Weins 1996).
Infection Severity Class Uninfected Light Medium Heavy Severe
0
.1-.25
.26-0.9
1.0-1.9 2.0+ Acres
Percent Infection 0 1-20% 20-50% 50%
Existing Condition 1,612 3,379 4,137 3,088 248 12,463
% of Infected Acres 12.9% 27.1% 33.2% 24.8% 2.0%
The relationship of tree dwarf mistletoe rating (DMR) to growth, mortality, and cone
production is summarized in table 6 for ponderosa pine. Dwarf mistletoe infection in
Douglas-fir has slightly higher reductions than ponderosa pine. In general, measurable effects
are observed with tree DMRs of 3 or greater. Infections in the lower portion of crowns tend
to have less significant effects than equal infections in upper portions. Additional
information can be found in appendix C.
Table 6. Relationship of tree DMR to growth, mortality, and cone production for ponderosa
pine (Hawksworth and Weins 1996).
White pine blister rust (an exotic disease) has recently been detected in eastern Arizona on
both the Apache-Sitgreaves National Forests (NF) and the Fort Apache Indian Reservation.
The effect of this disease is well-known throughout the U.S., and on the Lincoln National
Forest NF in New Mexico. White pine blister rust poses a threat to southwestern white pine,
causing severe mortality throughout its range. Some genetic resistance to this disease has
been identified on selected individual white pines on the Lincoln NF. For this reason, it is
critical that the full genetic diversity of southwestern white pine be maintained throughout its
range. Healthy white pines should be retained, favored and regenerated wherever possible.
Tree DMR
ITEM 0 1 2 3 4 5 6
% DBH Growth Reduction 0 0 0 2 14 27 50
% Height Growth Reduction 0 0 0 4 8 11 15
Cone Production Rating 2.9 2.3 2.3 2.2 1.6 0.8 0.04
% Increase in 10-year
Mortality rate
0 1 4 8 15 23 34
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Other Effects to Forest Health
Browsing of hardwood and conifer regeneration by livestock and game ungulates is heavy
throughout the area. The only tree species unaffected by browsing is southwestern white pine
(Fairweather 2008). In many locations, aspen clones are not successfully regenerating due to
browsing damage resulting from cattle, elk, deer, and other ungulate animal species.
Forest Structure – Goshawk Forest Habitat
Tables 7 and 8 display the existing forest structure within the goshawk FA and PFA habitats.
Three scales were used to examine existing VSS distribution and densities in goshawk forest
habitats, as directed by the forest plan: stand (fine-scale), compartment (mid-scale), project
(landscape). Details for these 3 levels can be found in the Wildlife Specialist Report. Stand-
level characteristics are most relevant to analysis of management treatments, so the stand
level analysis was used throughout this report to represent existing condition and for
simulation modeling of alternatives. The acreages for the stands were combined below for
the Larson area.
Table 7. Goshawk Foraging stands in 2015 by acreage percent.
Vegetative Structure
Stage
(VSS)
Tree Diameter Existing
% of Area
Forest Plan Desired
% Distribution *
1 – Grass/Forb/Shrubs 0.0 – 0.9” 0 10
2 – Seedling/Sapling 1.0 – 4.9” 3 10
3 – Young Forest 5.0 – 12” 57 20
4 – Mid-age Forest 12.0 – 17.9” 26 20
5 – Mature Forest 18.0 – 23.9” 12 20
6 – Old Forest 24”+ 2 20
* The forest plan standards and guidelines do not describe desired even-aged stand
conditions for goshawk foraging area habitat. It is desired to convert all foraging area even-
aged stands to the desired uneven-aged structural conditions.
Table 8. Goshawk PFA in 2015 by acreage percent.
Vegetative Structure
Stage
(VSS)
Tree Diameter Existing
% of Area
Forest Plan Desired
% Distribution
1 – Grass/Forb/Shrubs
2 – Seedling/Sapling
0.0 – 0.9”
1.0 – 4.9”
0 10
17 10
3 – Young Forest 5.0 – 12” 67 20
4 – Mid-age Forest 12.0 – 17.9” 0 20
5 – Mature Forest 18.0 – 23.9” 17 20
6 – Old Forest 24”+ 0 20
* The forest plan desired conditions applies to goshawk foraging and PFA habitat
only.
Existing condition for goshawk nest stands average 175 square feet of basal area
ranging from 111 to 230 square feet of basal area. Approximately 57% of the area is
in VSS 3 and 26% is in VSS 4.
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The existing even-aged stands are not desired for goshawk forest habitat except as nesting
stands. The existing uneven-aged forest structure does not comprise a balance of VSS
classes, and habitat components, such as canopy gaps (VSS 1 and 2)9. Interspaces between
groups of trees consisting of mixtures of grasses, forbs, and shrubs are lacking or limited in
most stands. VSS 3 and 4 are over-represented, and VSS 1, 2, 5 and 6 are deficit relative to a
balanced age/structure uneven-aged condition within the foraging areas. Goshawk PFAs have
an excess of VSS 3 and lacking the larger tree component.
Overall, uneven-aged stand conditions currently represent 66% of all goshawk habitat in the
project, with the remainder being even-aged. Of the even-aged stands, 25% is mid-aged to
mature (VSS 4+), and 75% is immature (VSS 1-3).
Since group VSS is determined by the predominant density within the group, this table does
not clearly show that there are many smaller trees, 1 to 5 inches in diameter, that are being
overtopped by larger trees. These smaller trees are often not free to develop due to the high
density of larger trees in the VSS 3 and 4 classes. Similarly, many of the larger trees greater
than 18 inches dbh, are competing with the densely stocked mid-aged trees for water and
nutrients. This decreases the vigor and longevity of these large trees.
Forest Structure – Mexican Spotted Owl
Structural habitat required for MSO recovery nest/roost habitat is below the required
minimums. Stands from the MSO recovery habitat were evaluated individually and averaged
in table 9 prior to selection of MSO nest/roost habitat. Details for each of the stands can be
found in appendix A. Other attributes of MSO habitat can be found in table 4 above.
Table 9. Existing condition for MSO recovery foraging habitat.
Forest Type Acres % of BA in
12-18 inch
dbh trees
% of BA in
>18 inch
dbh trees
Minimum
BA sq ft
Minimum
density of
trees > 18
inches
Mixed
Conifer
1,057 22% 29% 162 15
Pineoak 184 28% 14% 146 7
9 Canopy gaps are defined as regeneration of seedlings and saplings up to 5 inches in diameter.
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Old Growth
Old growth is analyzed at three scales: stand, project level, and district. In this case, the
Larson area is considered the project level (30,041 acres). Old growth standards seek to
allocate no less than 20% of each forested ecosystem management area and allocations
would consist of landscape percentages meeting old growth conditions and not specific areas
(USDA 1987, as amended 2009).
The forest plan defines old growth as a condition of the forest having structural attributes
based on the number of large trees per acre, basal area, canopy cover percent, dead standing
trees, and down logs. The three groups identified for developing old growth in the project
are interior ponderosa pine, aspen, and the mixed species group consisting of Douglas-fir,
white fir, and southwestern white pine.
The lower scale is represented by the stand level. All allocated old growth from past
management projects were mapped in the geographic information system (GIS). The
interdisciplinary team used this map, associated stand exam data, goshawk PFAs, and
Mexican spotted owl protected and recovery nest/roost habitat to identify developing old
growth stands for the project. The Black Mesa Ranger District old growth allocation was
used for the upper scale.
Approximately 4,561 acres, 15% of the forested project area, have been identified and
allocated through previous analyses to be managed towards old growth criteria. Stands
identified as MSO protected habitat, MSO recovery nest/roost habitat, and NOGO nest
stands, were allocated for old growth development across the district. Table 10 displays
acres currently allocated for old growth management on the Black Mesa Ranger District.
Areas currently allocated do not necessarily meet old growth standards in the forest plan but
are managed to move towards those conditions to meet old growth structural attributes over
time.
Current updates in the stand layer have left some of these old growth stands as unknown
cover types waiting for data collection processing which will occur later this year. Some
cover types have changed due to the Rodeo-Chediski Fire and have not been evaluated for
their current condition and are included in this unknown category.
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Table 10. Acres and percent of area allocated for developing old growth within the Larson
project and the Black Mesa Ranger District.
Old Growth
Forest Cover
Type
Larson
Total
Acres
Larson
Current
Old
Growth
Allocated
Acres
Larson
Current
Percent
Allocated
Black
Mesa
District
Acres
Current
District
Old
Growth
Allocated
Acres*
Black Mesa
District
Percent
Allocated
Aspen 63 0 0% 296 61 21%
Mixed Species 1,676 782 46.7% 18,302 9,131 50%
Ponderosa Pine 27,755 3,779 13.6% 295,848 51,270 17%
Unknown 74,326 2,802 4%
Desired Condition
The project desired conditions have been developed based upon the project purpose and need
and forest plan direction for forest vegetation management. Current best available science
was used for analysis of conditions necessary to meet the project Purpose and Need. Science
relative to historic reference conditions has informed this process.
Historic Range of Variability Background
Extensive research, particularly by Dr. Wallace Covington and colleagues of Northern
Arizona University, has demonstrated that current ponderosa pine forests of the Southwest
are greatly altered in terms of forest structure, density and ecological function. Most forest
conditions are at much higher risk of high intensity and severity fire than they were prior to
European settlement (Covington 1993, Moore et al. 1999). A century ago the pine forests had
widely-spaced large trees with a more open, herbaceous forest floor (Cooper 1960). Typical
historic tree group/patch size ranged from 0.1 to 0.75 acres in size, (2- 40+ trees) (White,
1985). These conditions were maintained by fairly frequent low-intensity ground fires that
did not kill the large trees (Fiedler et al. 1996). These fires occurred every 2 to 12 years and
maintained an open canopy structure (Moir et al. 1997). The herbaceous understory fueled
frequent fires started by lightning, and thinned and/or eliminated thickets of small trees
keeping the forest open and park-like (Allen et al. 2002). This historic range of variability
condition was estimated to have an average of 23-56 trees per acre on the Fort Valley
Experimental Forest, near Flagstaff, Arizona (Covington 1993). Dr. Margaret Moore reported
that on permanent plots located throughout Southwestern ponderosa pine forests, re-
measurements conducted during 1997-1999 show that average trees per acre have increased
by up to 33-fold since the plots were established in 1909-1913 (Moore et al. 2004).
Fire data collected in the Rim Lakes Forest Restoration Project adjacent to the Larson
project, indicates fire exclusion around 1880 with a fire return interval of 2 to 8 years
(Huffman 2013). Historically the majority of the Larson project area fell into the 30-40 trees per
acre range with an average of 35 trees per acre. There is not a real dramatic density difference
for one part of the project area versus another, based on evidence from data collected by the
Ecological Restoration Institute (ERI) in 2013 which is displayed in figures 6 and 7. The ERI did
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note that groups tended to have more trees per group in the south end of the project area
(Sensibaugh et al. 2013).
Figure 6. The X axis shows the number of historical structures per acre, which is the same as
the number of evidences recorded per plot. The Y axis shows the total number of plots that
recorded those numbers of historical structures. (Sensibaugh et al. 2013)
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Figure 7. This map displays the historical structure (trees per acre) across the project area, based
on the plot data. Note some areas on the map had limited samples and the accuracy of the
interpolation is likely to be lower than areas where the plots were clustered. (Sensibaugh et al.
2013)
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In his 1911 report, Woolsey reported approximately 31 trees per acre on his Sitgreaves NF
sample plots. Figure 8 compares trees per acre of all 1910 northern and central Arizona plots
aggregated together, and desired goshawk habitat conditions. Figure 8 displays the number
of trees per acre by size class for a single “fully-stocked” plot on high-site lands within the
Sitgreaves National Forest. Reporting on the general character of ponderosa pine forests,
Woolsey noted;
“The typical western yellow (ponderosa) pine forest of the Southwest is a pure park-
like stand made up of scattered groups of from 2 to 20 trees, usually connected by
scattering individuals. Openings are frequent and vary in size. Because of the open
character of the stand and the fire-resisting bark, often 3 inches thick, the actual loss
in yellow (ponderosa) pine by fire is less than with other more gregarious species. A
crown fire in mature timber is almost unheard of, and in a ground fire in the virgin
forest young saplings often escape complete destruction, though with a fair wind and
on a steep slope destruction of seedlings and saplings is often complete…In June
1910, a fire occurred on the Gila, Datil and Apache National Forests which burned
over about 60 square miles. The area burned was steep and rocky, with an unusual
quantity of dry forage. An investigation showed that injury to the yellow (ponderosa)
pine was confined very largely to the reproduction. On the area as a whole, from 40
to 50 percent of the seedlings were killed (Woolsey 1911).”
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Figure 8. Trees per acre by diameter class in 1910 (Woolsey 1911) on a single large
area Sitgreaves NF plot (fully-stocked, high-site) and comparison of desired condition.
*No historic data was collected for 0 to 4 inch trees on the 1910 plot.
Historic mixed conifer forests were typically uneven-aged in structure, and tree spatial
patterns varied from open and clumped to moderately-sized homogeneous patches. Density
ranged from open to moderately dense. The warmer, drier mixed conifer forest types
experienced more frequent fire intervals and were typically uneven-aged, growing in a
patchy structure, contained many fewer trees per acre than existing stands and experienced
relatively frequent low to moderate intensity fire, similar to ponderosa pine forests. The
cooler, wetter mixed conifer forest types historically experienced less frequent, moderate
intensity fire, resulting in larger patches of homogeneous tree ages and higher patch density
overall (Smith 2006). Due to the frequent disturbance regime, historic species composition
in the warmer, dryer mixed conifer forests was dominated by fire resistant, shade-intolerant
conifer species such as ponderosa pine, southwestern white pine and Douglas-fir. Historically
shade tolerant species were absent or present as a minor stand component on the drier sites
such as ridge tops and southwest-facing slopes, with more abundant but still subdominant
representation on cooler, wetter, north-facing slopes.
0
5
10
15
20
25
30
35
40
4-6* 7-12 13-18 19-24 25+
Historic (1910) 2.2 7.6 8 5.6 7.6
Foraging Area Desired Condition
39.6 27.3 9.3 6.1 4.2
PFA Desired Condition 39.6 27.3 13.8 7.7 5.5
Tre
es
pe
r A
cre
Comparison Trees per acre by Diameter Class Historic (1910) to Desired Condition for Goshawk Habitat
Historic ≈ 60 BA PFA = 70 BA FA = 55 BA
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While it is not considered necessary, or even desirable in some cases, to mimic these
conditions throughout our pine and mixed conifer forests today, it does represent conditions
that are more synchronous with the natural disturbance regime to which this ecosystem is
adapted. Social, political and economic factors are much different today than a century ago
and there are valid considerations for leaving areas of higher tree density to meet
management needs. But restoration of some portion of the landscape to conditions
reminiscent of pre-European settlement times would provide greater ecosystem stability and
sustainability.
General Desired Conditions
Uneven-aged forest structures comprise a distribution of age classes and seral stages.
Overall, the Larson project is dominated by early seral, shade intolerant forest species that
are most resilient to fire effects. Aspen, oak, and other hardwood species are well-
represented and are regenerating successfully across the landscape, where local forest bio-
physical conditions are appropriate for development of these species. Overall, forests are
generally vigorous with endemic levels of native insect and disease occurrences, and contain
a dominant component of ponderosa pine, Douglas-fir, and southwestern white pine.
Southwestern white pine is present throughout the mixed conifer forest type, a wide range of
genetic diversity is present, and the species is regenerating in suitable locations.
A variety of forest density, spatial arrangement, age, and structure conditions exists across
the landscape comparable to historic conditions. Conifer forest types are composed of a
distribution of age classes that comprise a sustainable balance of structural stages described
in the following Vegetative Structure section, and meet forest plan guidelines (USDA 1987,
as amended 2009). Forest canopy gaps consisting of seedlings and saplings occur on 20% of
each stand area (excluding MSO protected and recovery nest/roost habitat, and goshawk
nesting areas). Canopy gaps and openings mimic historic spatial patterns and provide for;
regeneration of shade intolerant tree species, development of grass-forb-shrub interspaces,
rooting zones for tree group development, and facilitate re-introduction and maintenance of
frequent surface fire as an ecological process. Forest canopy gaps and interspaces are
dynamic over time shaped by small-scale disturbances and vegetation development, with
some areas developing into new tree groups and patches, while other areas remain as
openings that contribute to ecosystem diversity by supporting tree group rooting zones and
grass-forb-shrub interspaces (USDA 2013). Managed uneven-aged stands range from 15%
to 45% of maximum SDI are based upon project purpose and need objectives and the forest
vegetation development principles displayed in table 4. In areas outside of MSO protected
and recovery habitats, basal areas average less than 80, and bark beetle hazard is low.
Ponderosa pine and mixed conifer forest types exhibit uneven-aged characteristics (multi-
storied), except for stands focused on providing NOGO nest and MSO protected and
recovery nest/roost habitats.
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Stand Density
A great variety of stand and tree characteristics can be developed by varying the timing,
scale, and intensity of density management. A few examples follow:
•Grassy stands of open canopy, large-diameter trees with long, heavy-limbed crowns can be
produced by maintaining densities in zones 1 and 2.
•Regeneration of desired species can be initiated by maintaining stand density in zone 1
(based on desired species maximum SDI).
•Stands of moderately dense canopy, intermediate-sized trees with thrifty, well-pruned
crowns could be developed by maintaining densities in the upper half of zone 2 and the lower
half of zone 3.
•Clumpy, irregular stands containing groups of varying ages might be developed through
periodic creation of openings where growing space (regeneration group openings) is made
available for seedling establishment. Growing space areas would fall into zone 1.
•Longevity of existing old-growth trees might be enhanced by thinning adjacent smaller trees
to create zone 2 or 3 growing conditions.
•Avoiding density-related mortality and maintaining forest vigor can be achieved by
maintaining densities at or less than the lower half of zone 3 (The forest plan directs that
forest stands be managed at conditions that promote and maintain good vigor.)
Insects and Disease
Healthy forest conditions facilitate capacity to store carbon by minimizing tree losses to
wildfires, insects, and diseases. Vigorous growth conditions promote resistance to insect and
diseases. Products provided for biomass serve to reduce use of fossil fuels by society.
Forests within the project area provide a sustainable supply of diverse uses and values while
contributing to stabilization of the Earth’s climate.
Dwarf mistletoe is an element of the forest landscape. There is a varied level of mistletoe
across the landscape, comparable with historic conditions such that it does not impede
achieving and sustaining desired uneven-aged forest conditions. Desired stand dwarf
mistletoe infection levels do not exceed 20% infection of the host species (trees per acre
basis), or 25% of the area infected for any given tree species (Conklin and Fairweather
2010). Dwarf mistletoe infections are irregularly distributed among tree groups, such that
effects are limited to the forest group and patch scale. The desired condition is to reduce the
amount of infection with the majority of stands in the uninfected to moderate infection range.
Bark beetle hazard is low to moderate with a BA of less than 100 square feet and a variety of
tree size classes in groups across the landscape.
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Forest Structure
Desired forest structure conditions are uneven-aged forests with a balance of structural stages
(age classes), arranged in a clumped, open forest condition (excepting MSO protected and
recovery nest/roost habitats, and goshawk nest habitats). A primary objective is the
restoration of sustainable forest mosaic patterns with canopy gaps and forest openings
totaling 20% of stand areas to facilitate uneven-aged forest stand dynamics and other
ecological functions. One element of the proposed treatments is the initiation of conditions
conducive to regenerate or develop VSS 1 and 2 classes (establish or release existing
seedlings/saplings), totaling approximately 20% of the open area. The target regeneration gap
size for foraging areas would be from 0.25 to 4 acres in size (most averaging 0.33 to 0.75
acres). The target regeneration gap size for PFAs would be from 0.25 to 2 acres in size (most
averaging 0.33 to 0.75 acres). When regeneration openings exceed one acre in size, 5 to10
desirable seed trees per acre would be retained, and 3 to 5 of these seed trees should be at
least 15 inches dbh and larger. Regeneration openings smaller than 0.33 acre would not
effectively facilitate regeneration and future development of tree groups of sufficient area
necessary to produce and sustain desired wildlife habitat conditions. No created regeneration
would exceed four acres in size (goshawk FAs) or two acres in size (goshawk PFAs). The
objectives for the remainder of the developed/maintained forest opening areas are to provide
for other ecological functions.
Forest Structure - Goshawk Habitat Ponderosa Pine Goshawk Nest areas: A high canopy cover (basal area equals or exceeds 120
ft.2/acre) of mature to old age trees exists.
Ponderosa Pine Goshawk Post-Fledging Family Area (PFA) Habitat: Balanced uneven-aged
condition (stand area basis). Canopy cover for mid-aged forest (VSS 4) should average 1/3
60+% and 2/3 50+%. Mature (VSS 5) and old forest (VSS 6) should average 50+%. (table
11). Basal area averages from 70-80 ft2
(see appendix C), 2 snags per acre >18” diameter, 3
downed logs per acre 12” diameter and 8’ long, and 5-7 tons of woody debris >3” diameter.
Ponderosa Pine Goshawk Foraging Area (FA) Habitat: Balanced uneven-aged condition
(stand area basis) with 40% canopy cover within the VSS 4-5-6 classes (table 12). Maintain
average basal area from 50-60 ft2
(see appendices A and C), 2 snags per acre >18” diameter,
3 downed logs per acre 12” diameter and 8’ long, and 5-7 tons of woody debris >3” diameter.
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Table 11. Desired stand structure condition, Ponderosa Pine Goshawk PFA Habitat
VSS DBH % of Mean Canopy
Class Class Area DBH SDI1
tpa BA/Ac Cover tpa BA/Ac
1 <1 10 0.1 0 203 0 20.3 0
2 1-4.9 10 3 28 193 9 19.3 1
3 5-11.9 20 8.5 105 136 54 27.3 11
4 12-17.9 7 15 137 72 88 60+ 4.8 6
4 12-17.9 13 15 130 68 83 50+ 9.0 11
5 18-23.9 20 21 127 39 93 50+ 7.7 19
6 24+ 20 27 135 27 109 50+ 5.5 22
93.9 69
Dq* = 13.11
SDI* = 113.7
DESIRED CONDITION
Group basis
Reserve trees and grass matrix areas are included in
these figures. Trees are closely grouped, allowing for
open rooting zones between groups.
*Includes trees >=
1" dbh only.
Ponderosa Pine - Average - Goshawk Post-Fledging Family Area
Mean Mean
Per acre basis
====== Note on per acre basis =======
}20%
1
1SDI maximum values = SDI/450 x 100
SDI, tpa, and BA are inferred from the forest plan. See appendices A & C.
Table 12. Desired stand structure condition -Ponderosa Pine Goshawk FA Habitat
VSS DBH % of Mean Canopy
Class Class Area DBH SDI 1
tpa BA/Ac Cover tpa BA/Ac
1 <1 10 0.1 0 203 0 20.3 0
2 1-4.9 10 3 28 193 9 19.3 1
3 5-11.9 20 8.5 105 136 54 27.3 11
4 12-17.9 20 15 89 46 57 40+ 9.3 11
5 18-23.9 20 21 100 30 73 40+ 6.1 15
6 24+ 20 27 104 21 84 40+ 4.2 17
86.5 54
Dq* = 12.29
SDI* = 92.1
Ponderosa Pine - Average - Goshawk Foraging Area
====== Note on per acre basis =======
Reserve trees and grass matrix areas are included in
these figures. Trees are closely grouped, allowing for
open rooting zones between groups.
DESIRED CONDITION
*Includes trees >=
1" dbh only.
Group basis Per acre basis
Mean Mean
1SDI maximum values = SDI/450 x 100 SDI, tpa, and BA are inferred from the forest plan. See appendices A
& C.
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Forest Structure – Mexican Spotted Owl
MSO Protected Core Habitat (amended forest plan requirements): No mechanical
treatments, broadcast burning allowed.
MSO Protected Habitat Outside Core (amended forest plan requirements): Trees greater than
16” dbh are retained following management treatments. Retain hardwood species.
MSO Habitat Recovery Nest/Roost (amended forest plan requirements): Manage for
nest/roost replacement habitat and do not lower below those found in table 13. Emphasize
attainment of nest/roost as soon as possible. Retain large trees which are defined as 18
inches dbh and larger.
MSO Habitat Recovery Foraging Habitat (amended forest plan requirements): Emphasize
large hardwoods and retain key owl habitat elements.
Table 13. MSO recovery habitat requirements for nest/roost habitat.
Forest Type % of area % of BA in
12-18 inch
dbh trees
% of BA in
>18 inch
dbh trees
Minimum
BA sq ft
Minimum
density of
trees > 18
inches
Mixed Conifer 25 >30 >30 120 12
Pine Oak 10 >30 >30 110 12
Environmental Consequences
Effects common to all alternatives
Alternatives 2 and 3 do not include any activities directed toward changing vegetation types.
All treatments proposed would not change the vegetative cover types. Road obliteration
proposed under alternatives 2 and 3 would provide a seed bed allowing for regeneration and
restoration of the road beds. Road improvements proposed would have no effect to the
vegetation or change in forest structure.
Stands that would be left untreated in all alternatives would continue to become denser and
decrease in vigor and health over time. Grass-forb-shrub presence would decrease, and
growth would continue to decline. No canopy gaps would be created for seedling
regeneration, or to restore forest interspace. Growth of trees would be slower than the treated
stands.
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Alternative 1 – No Action
No vegetation management activities are proposed under alternative 1. No opportunities for
timber or other biomass products to be produced, and no costs would be incurred for thinning
or burning treatments.
Direct and Indirect Effects
Stand Density
Under this alternative, no forest vegetation treatment activities would occur. Stand
densities would not be reduced. Stand densities and BA in the years 2020 and 2035 are
displayed in tables 14 and 15. Assuming no disturbance such as fire or insect outbreaks,
over the next 20 years, growth modeling simulation shows that stand densities would
increase to levels ranging from an average of 45-71% of maximum stand density in 2035
(table 15). These density levels are at the threshold or well within zone 4 of density-
related mortality (table 3).
Insects and Disease
Bark beetle hazard is moderate over much of the analysis area, and would increase as stands
become denser. Alternative 1 has the highest bark beetle hazard as shown in tables 14 and
15, and would result in higher probable tree mortality than alternatives 2 and 3.
Dwarf mistletoe in ponderosa pine and Douglas-fir would continue to intensify within the
areas of current infections, and the size of the current infection centers would slowly spread
over time. Dwarf mistletoe would continue to impact regeneration, reduce cone production,
reduce dbh and height, and reduce survival of sapling-sized trees. Over time (2 to 4 decades)
this would severely limit sustainability of uneven-aged stands where current infection levels
exceed 25% of host trees (40% of the analysis area). Tables 20 and 21, show the comparison
of alternatives with the majority of stands in the heavy to severe infection levels. Trees with
severe dwarf mistletoe infection levels exhibit low vigor overall, and these trees are more
susceptible to bark beetle and density-induced mortality (tables 14 and 16). Resistance to
bark beetle mortality would continue to decline due to increased density and rise of mistletoe
infection.
None of the alternatives affect forest carbon storage to any measurable level. Alternative 1
has the highest potential to release carbon in a relatively large quantity over a short period of
time, due to increased fire hazard with increased risk of stand-replacing wildfire.
Forest Structure
The primary forest vegetation management direction found in the forest plan (USDA 1987,
as amended 2009) is to develop or maintain sustainable uneven-aged forest structure. Under
alternative 1, no conifer regeneration treatments would occur. Even-aged stands would
remain even-aged in structure, and no new age classes would be created and/or managed.
Uneven-aged stand structures would not be maintained over time, due to lack of regeneration
of new age classes. Restoration of sustainable forest mosaic patterns with canopy gaps and
forest openings would not occur, and canopy continuity would remain high throughout the
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July 30, 2014 Page 33 of 67
project area. Mixed conifer forest stands would continue to be dominated by shade tolerant
species, or would continue to convert to dominance of these species over time. No forest
habitat or allocated old growth stands would be treated to improve health and vigor of the
stand, or to manage forest structure towards desired conditions. Natural meadows and
openings would not be maintained. Quaking aspen and Gambel oak patches would not be
released or favored to develop. Opportunities to favor and regenerate Southwestern white
pine would not occur under this alternative.
Forest Structure – Goshawk
Tables 16 to 19 and graphs 1 to 4 display the VSS classes for the FA and PFA over time.
Approximately 84% of the foraging area would be dominated by VSS 3 and 4 with little
change overtime. The PFA stands would lose the large tree classes as VSS 2, 3, and 4
become the dominant groups due to mortality in the large trees and the large number of trees
in the smaller age classes across the landscape. This alternative moves away from the
desired condition and becomes more even-aged overtime.
Forest Structure – Mexican Spotted Owl
This alternative more closely meets the desired condition for density in the recovery
nest/roost habitat than alternatives 2 and 3 as no broadcast burning or thinning would occur.
Stands continue to get denser with a gradual increase in BA. Basal area percentages
themselves do not change and are the same as alternative 2 and 3 (table 22).
Old Growth
Alternative 1 would not meet the forest plan percentages for allocated old growth within the
project area as no additional stands would be allocated for old growth management (table
10). Stands identified under past timber sale decisions would continue to be managed as
allocated old growth, and tree size development would be limited by existing high stand
density. Stands would not receive thinning or burning to reduce the fire hazard or improve
health and individual tree growth. Stand density would continue to increase reducing the
growth and health of the larger trees. Stands with potential to develop towards quality old
growth characteristics may or may not achieve these objectives without receiving restorative
management treatments.
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Table 14. Post-treatment (2020) stand density, basal area, beetle hazard.
*Aspen not established to show an increase in measureable stems due to 2 burn entries.
** Minimum BA would be required even though modeling shows a drop below the required.
Alt 1 Alt2 Alt3 Alt 1 Alt2 Alt3 Alt 1 Alt2 Alt3
Description
Max%
SDI
Max
%
SDI
Max
%
SDI BA BA BA
Beetle
Hazard
Beetle
Hazard
Beetle
Hazard
Ma
x%
SDI Max%
SDI Max%
SDI BA BA BA Beetle
Hazard Beetle
Hazard Beetle
Hazard
Goshawk Foraging
Aspen Treatment 64% 3% 5% 186 10 15 High Low Low
Group Selection /
Intermed Thin 55% 25% 26% 161 68 76 High Low Low
Group Selection /
Intermed Thin - Old
Growth <18” 50% 43% 43% 148 110 109 High Moderate Moderate
Intermediate Thin 52% 31% 33% 159 87 87 High Moderate Moderate
Burn Only 60% 62% 61% 170 148 146 High High High
PreCommercial Thin 45% 44% 44% 132 117 118 High High High
Shelterwood 46% 29% N/A 140 75 N/A High Low N/A
Goshawk Nest
Burn Only 66% 64% 64% 185 154 154 High Moderate Moderate
Goshawk PFA
Group Selection /
Intermediate Thin 65% 41% 24% 175 102 69 High Moderate Low
PreCommercial Thin 62% 52% 51% 162 133 133 High High High
Protected Core
Burn Only 58% 54% 54% 187 135 135 High High High
Protected Outside Core
Intermediate Thin <16” 51% 54% 54% 157 140 140 High High High
Burn Only 39% 46% 46% 117 111 109 High Moderate Moderate
PreCommercial Thin 50% 40% 39% 150 103 100 High Moderate Moderate
Recovery Foraging
Group Selection /
Intermediate Thin 54% 32% 29% 174 81 78 High Moderate Moderate
Burn Only 57% 56% 56% 176 131 132 High High High
PreCommercial Thin 54% 29% 29% 185 82 80 High Moderate Moderate
Recovery Nest / Roost
Group Selection /
Intermediate Thin** 47% 35% 35% 159 74 74 High Low Low
Burn Only 53% 48% 48% 178 110 110 High Moderate Moderate
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Table 15. Post-treatment following burn entries (2035) stand density, basal area, beetle
hazard.
** Broadcast burning that was modeled appears to have dropped the BA below the
minimum.
Alt 1 Alt2 Alt3 Alt 1 Alt2 Alt3 Alt 1 Alt2 Alt3
Description
Max%
SDI
Max%
SDI
Max%
SDI BA BA BA
Beetle
Hazard
Beetle
Hazard
Beetle
Hazard
Goshawk Foraging
Aspen Treatment* 70% 5% 5% 211 17 17 High Low Low
Group Selection /
Intermed Thin 63% 29% 29% 189 82 86 High Moderate Moderate
Group Selection /
Intermed Thin - Old
Growth <18” 55% 38% 37% 167 103 101 High Moderate Moderate
Intermediate Thin 59% 30% 33% 184 93 94 High Moderate Moderate
Burn Only 61% 48% 50% 180 130 133 High High High
PreCommercial Thin 51% 40% 40% 152 113
115 High Moderate High
Shelterwood 55% 17% N/A 168 51
N/A High Low N/A
Goshawk Nest
Burn Only 71% 51% 51% 207 138
138 High High High
Goshawk PFA
Group Selection /
Intermediate Thin 71% 39% 28% 200 105 81 High Moderate Moderate
PreCommercial Thin 71% 47% 47% 183 128 127 High High High
Protected Core
Burn Only 67% 44% 44% 221 119 119 High Moderate Moderate
Protected Outside Core
Intermediate Thin <16” 59% 46% 46% 182 128 127 High High High
Burn Only 45% 40% 42% 140 103 103 High Moderate Moderate
PreCommercial Thin 59% 36% 35% 179 98 96 High Moderate Moderate
Recovery Foraging
Group Selection /
Intermediate Thin 62% 27% 26% 206 80 75 High Moderate Low
Burn Only 66% 43% 43% 211 111 113 High Moderate Moderate
PreCommercial Thin 67% 29% 27% 230 86 82 High Moderate Moderate
Recovery Nest / Roost
Group Selection /
Intermediate Thin** 59% 20% 20% 201 43 43 High Low Low
Burn Only 63% 34% 38% 202 86 90 High Moderate Moderate
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Table 16. Goshawk FA VSS comparison in 2020 (post-treatment).
VSS Class Alternative 1
% of the area
Alternative 2
% of the area
Alternative 3
% of the area *
VSS 1 0 10 10
VSS 2 2 10 10
VSS 3 39 6 8
VSS 4 45 34 28
VSS 5 11 24 33
VSS 6 2 19 13
Graph 1. VSS Comparison for the year 2020 for goshawk foraging.
0 5
10 15 20 25 30 35 40 45
VSS 1 VSS 2 VSS 3 VSS 4 VSS 5 VSS 6
Alternative 1 0 2 39 45 11 2
Alternative 2 10 10 6 34 24 19
Alternative 3 10 10 8 28 33 13
Desired Condition 10 10 20 20 20 20
Pe
rce
nt
by
VSS
Cla
ss
VSS Comparison 2020 Foraging Area
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Table 17. Goshawk FA VSS comparison in 2035 (VSS development over time).
VSS Class Alternative 1
% of the area
Alternative 2
% of the area
Alternative 3
% of the area *
VSS 1 0 10 10
VSS 2 6 10 10
VSS 3 32 14 2
VSS 4 52 18 8
VSS 5 5 24 45
VSS 6 2 24 25
Graph 2. VSS Comparison for the year 2035 for goshawk foraging.
Table 18. Goshawk PFA stand VSS comparison in 2020 (post treatment).
VSS Class Alternative 1
% of the area
Alternative 2
% of the area
Alternative 3
% of the area *
VSS 1 0 10 10
VSS 2 17 10 10
VSS 3 64 20 12
VSS 4 3 45 42
VSS 5 17 0 0
VSS 6 0 15 26
0
10
20
30
40
50
60
VSS 1 VSS 2 VSS 3 VSS 4 VSS 5 VSS 6
Alternative 1 0 6 32 52 5 2
Alternative 2 10 10 14 18 24 24
Alternative 3 10 10 2 8 45 25
Desired Condition 10 10 20 20 20 20
Pe
rce
nt
by
VSS
Cla
ss
VSS Comparison 2035 Foraging Area
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Graph 3. VSS Comparison for the year 2020 for goshawk PFA.
Table 19. Goshawk PFA stand VSS comparison in 2035 (VSS development
over time).
VSS Class Alternative 1
% of the area
Alternative 2
% of the area
Alternative 3
% of the area *
VSS 1 0 10 10
VSS 2 42 10 10
VSS 3 38 14 2
VSS 4 21 38 44
VSS 5 0 13 14
VSS 6 0 15 20
*In most uneven-aged and mid-even-aged stands it would be difficult to create regeneration
openings and interspace with a 16 inch diameter limit constraint.
0
10
20
30
40
50
60
70
VSS 1 VSS 2 VSS 3 VSS 4 VSS 5 VSS 6
Alternative 1 0 17 64 3 17 0
Alternative 2 10 10 20 45 0 15
Alternative 3 10 10 12 42 0 26
Desired Condition 10 10 20 20 20 20
Pe
rce
nt
VSS
by
Cla
ss
VSS Comparison 2020 PFA
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Graph 4. VSS Comparison for the year 2035 for goshawk PFA.
Table 20. Dwarf mistletoe severity based on stands with current data in 2020 (12,462 acres).
Infection Severity Class by
Percent of infection
None Light Medium Heavy Severe
0 .1-.25 .26-0.9 1.0-1.9 2.0+
Alternative 1
12% 13% 40% 31% 5%
Alternative 2
66% 12% 13% 9% 0%
Alternative 3
14% 30% 46% 7% 3%
Table 21. Dwarf mistletoe severity based on stands with current data in 2035 (12,462).
Infection Severity Class by
Percent of infection*
None Light Medium Heavy Severe
0 .1-.25 .26-0.9 1.0-1.9 2.0+
Alternative 1
12% 2% 13% 53% 20%
Alternative 2
70% 3% 16% 8% 3%
Alternative 3
14% 12% 61% 9% 3%
*Does not include latent infections which may be present in the stand but not detected until
after treatment.
0
5
10
15
20
25
30
35
40
45
VSS 1 VSS 2 VSS 3 VSS 4 VSS 5 VSS 6
Alternative 1 0 42 38 21 0 0
Alternative 2 10 10 14 38 13 15
Alternative 3 10 10 2 44 14 20
Desired Condition 10 10 20 20 20 20
Pe
rce
nt
VSS
by
Cla
ss
VSS Comparison 2035 PFA
Larson Forest Restoration Project Silviculture Specialist Report
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Table 22. MSO recovery nest/roost habitat in 2020.
Alternative Forest Type % of
acres
% of BA
in 12-18
inch dbh
trees
% of BA
in >18
inch dbh
trees
Minimum
BA sq ft*
Minimum
density of
trees > 18
inches
1
Mixed
Conifer
40% 21% 34% 174 18
Pineoak 81% 29% 12% 147 6
2
Mixed
Conifer
40% 18% 29% 120 9
Pineoak 81% 29% 12% 129 5
3
Mixed
Conifer
40% 18% 28% 120 8
Pineoak 81% 29% 12% 129 5
*Minimum BA would be required is prescriptions
Alternative 2
Alternative 2 proposes to conduct commercial and non-commercial thinning using
mechanical equipment. This alternative proposes management of forest density and structure
by implementation of uneven-aged selection cutting in all stands managed for northern
goshawk PFA and FA forest habitat, and all stands managed for MSO recovery foraging
habitat. Meadow enhancement is proposed for small meadows and wetlands within the
project area. MSO protected habitat stands would be thinned from below 16 inches dbh.
Shelterwood with reserves would be used to reduce dwarf mistletoe on 721 acres resulting in
two mechanical entries. MSO recovery nest/roost habitat would be thinned from below to
meet the desired condition for forest plan density criteria. Prescribed fire would be used to
reduce natural and treatment fuels in both thinned and un-thinned areas. Opportunities for
timber or other biomass products would be produced, and costs would be incurred for
thinning and burning treatments under alternative 2. Table 23 displays a comparison of
treatment acres by forest stratum. See the silvicultural prescription details in appendix B.
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July 30, 2014 Page 41 of 67
Direct and Indirect Effects
Alternative 2 moves the treated areas towards healthier forest conditions by managing for
unevenaged conditions, restoring vigorous growth conditions and reducing losses due to tree
mortality, high-severity wildfire, and insects and diseases.
Stand Density
Compared to Alternatives 1 and 3, Alternative 2 would be most effective for increasing forest
health and vigor, thereby improving forest resiliency and sustainability to stresses such as
insects, disease, and climatic variability. Based upon all forest stands (treated and untreated),
90% of northern goshawk habitat forest types (by area) and 100% of MSO recovery habitat
foraging habitat (by area) are projected to meet desired maximum density conditions post-
treatment (tables 14 and 15 and appendix A). Old growth stands that retain all trees 18
inches dbh and greater are still in zone 3 and considered high density.
In MSO protected habitat outside core forest areas (where thinning is restricted to cutting
trees up to a maximum 16 inches dbh), a reduction of excess density in understory trees
would occur, but overall forest canopy cover and continuity would remain unchanged.
Effects on forest health and vigor would be minimal as a result of these treatments, but minor
improvements in the ability to implement and control prescribed fire treatments would be
realized.
Insects and Disease
Of the three alternatives, this alternative is the most effective treatment for reducing bark
beetle hazard as the majority of the area moves towards uneven-aged conditions faster than
alternatives 1 and 3. Decreasing stand densities would release dominant10
and co-dominant11
trees allowing them to become more vigorous, more resistant to insect and diseases
(McMillin 2004), and grow at a faster rate into larger tree size classes. After treatment, it is
projected that approximately 70% of the analysis area would be in the low hazard category
(tables 14 and 15). On 16% of the analysis area, beetle hazard remains high due to stands
which would not receive treatments that reduce forest canopy density (no treatment,
broadcast burning only treatment, or limited treatment –MSO protected and recovery
habitats, steep slopes). The remaining 14% is reduced to moderate with a short term effect.
10
Dominant – trees that receive full light from above the canopy and partially from the sides. Crowns extend
above the general level of the canopy (USDA 1987). 11
Codominant – Tree crowns receive full light from above, but comparatively little from the sides (USDA
1987).
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Table 23. Proposed treatment acres for alternatives 2 and 3.
Proposed Treatments Alt 2 Alt 3
Goshawk Habitat
Foraging Shelterwood with Reserves 721 0
Foraging Group Selection/Intermediate Thinning 20,383 0
Foraging Group Selection/Intermediate Thinning Old Growth < 18" 1,653 0
Foraging Intermediate Thinning 497 0
PFA Group Selection/ Intermediate Thinning 423 0
Foraging Group Selection/Intermediate Thinning <16” 0 20,383
Foraging Group Selection/ Intermediate Thinning Old Growth < 16” 0 1,653
Foraging Intermediate Thinning <16” 0 497
PFA Group Selection/ Intermediate Thinning < 16” 0 423
Foraging Intermediate Thinning < 9" 92 92
Mexican Spotted Owl Habitat
Recovery Foraging Group Selection/Intermediate Thinning 197 0
NestRoost Group Selection /Intermediate Thinning 31 0
Protected Outside Core Intermediate Thinning <16" 668 668
Recovery Foraging Group Selection/Intermediate Thinning <16” 0 197
NestRoost Group Selection /Intermediate Thinning <16” 0 31
Protected Outside Core - Intermediate Thinning <9" 707 707
Recovery Foraging - Intermediate Thinning <9" 31 31
Prescribed Burning Only ( all habitat types) 4,012 4,733
Meadow & Riparian Enhancement 47 47
Aspen Enhancement (currently identified) 115 115
This alternative would provide opportunities to manage dwarf mistletoe severity, incidence,
and distribution; in order to move towards desired endemic forest disease levels within the
project area (tables 20 and 21). Treatments would alternately focus on removal of infected
trees in locations where new regeneration groups (VSS 1) would be established or favored,
and where canopy gaps would be developed or restored. Elsewhere within the stands,
treatment would focus on reduction of the percentage of severely infected trees. Severe dwarf
mistletoe infection centers are typically circular in shape, but seldom exceed 4 acres in size.
Adherence to the 200 feet opening width limitation (forest plan guidelines) would in some
instances limit the ability to create replacement regeneration openings sufficient to manage
dwarf mistletoe towards desired conditions.
The restoration of forest interspace openings would greatly reduce continuity of mistletoe
occurrence, spread, and mortality; such that the host-pathogen biological dynamics function
similar to historic conditions. Generally, the focus would be on treating dwarf mistletoe
locations, severity and spread potential such that it is present at endemic levels that do not
jeopardize short- and long-term attainment of desired forest vigor, structure, and species
composition. In mixed conifer stands, non-host species would be favored over severely
diseased trees, as local forest conditions permit. Where diseased single trees greater than 16
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inches dbh exist, they would be removed to favor other trees or promote regeneration on
forest lands managed for northern goshawk habitat.
This alternative has the greatest overall reduction in the percent of mistletoe infection (table
20). Individual tree DM ratings would be lower than alternatives 1 and 3 resulting in
increased cone production, and the greatest percent increase of height and dbh growth (table
6). Dwarf mistletoe infection does increase over time due to latent infections which cannot
be seen until after treatments are completed and growth begins to increase as a result of more
open stand conditions. Table 21 reflects the additional shelterwood removal in 2025 which is
reflected in the improved DM percentages in 2035 over alternatives 1 and 3.
This alternative also provides maximum flexibility to manage for maintenance or
improvement of forest genetics. In many locations, historic high-grade cutting has resulted in
mature seed trees with “poor-formed” (stunted) characteristics, relative to the original genetic
diversity that existed prior to cutting. Many of these genetically-stunted trees do not develop
into VSS 6 forest structural stages or large individual trees, even at advanced ages.
Therefore, most of these trees remain small in size relative to age, and neither these trees nor
their progeny develop desirable mature forest habitat characteristics. In some locations, it
would be advantageous to remove these individual “poor-formed” trees to favor seed trees
with more desirable and “normal-formed” traits. On a case-by-case basis, alternative 2
permits the favoring of seed trees with desirable growth traits over those remnant examples
of the poorest-formed individuals from the original forest stands. Based upon forest plan
direction, all VSS 6 groups would be retained where they occur throughout the project area
except in situations when occasional trees may be removed in order to provide understory
health and development or for safety.
Forest Structure
Existing even-aged stands would be managed to develop a new age class, and would become
two-aged stands within one decade post-treatment. Existing uneven-aged stand structures
would be maintained as uneven-aged stands, and managed over time to develop a balance of
age classes in a mosaic of tightly-interspersed structural groups. Restoration of sustainable
forest mosaic patterns would occur, and the resulting forest canopy would be discontinuous
and clumped throughout much of the area, based upon desired conditions.
Forest Structure - Goshawk
Stands would be evaluated to determine excess or deficit vegetation structural stages (VSS
age classes) and groups/individual trees would be removed or favored to move towards the
desired balance. Alternative 2 moves forested vegetation conditions for goshawk closer to the
desired conditions than alternatives 1 and 3. Tables 16 and 17 show the most balanced
unevenaged conditions meeting VSS 4, 5, and 6. In 2035 the desired conditions for VSS
distribution would be met and stands would be considered unevenaged. Graphs 1 to 4 show
alternative 2 having the greatest improvement towards the desired condition VSS percentages
for the FA but less desired for the PFA than alternative 3.
The Eagar South example treatment (Sitko and Hurteau 2010) represents the same
silvicultural treatment strategy proposed under alternative 2 for management of goshawk
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PFA and FA forest habitats. The example area is an average to above average productivity
ponderosa pine site. Prior to treatment, all VSS classes were represented to some degree
(although not in balanced proportion) and low/moderate severity of dwarf mistletoe was
present throughout the stand. This stand is very similar to many of the uneven-aged stands
existing within the project area. See example treatment area in figures 9a-c. Eagar South
Goshawk PFA Management Area, and Pre and Post Treatment Stand Conditions (figure 10).
Regeneration openings and interspace were created on approximately 26% of the area (14%
of the created openings ranged from 0.33 to 1.4 acres in size). After implementation of an
uneven-aged selection cutting prescription, without diameter cap constraints, the following
objectives were achieved on the Eagar South treatment area:
1) Regeneration group openings of sufficient size were established on sufficient areas to
develop and maintain uneven-aged forest conditions; and
2) Grouped tree spatial patterns were maintained and created; and
3) Stand canopy continuity was broken (provide habitat diversity and greatly reduce crown
fire potential) and;
4) Progress towards a balance of VSS classes was promoted (balanced representation was
maintained/promoted, but overall balanced VSS was not achievable during this initial
treatment).
While each stand within the project varies by forest structure and other conditions, it is
expected that many of the same post-treatment outcomes can be achieved in existing uneven-
aged stands through implementation of the like treatment prescriptions proposed for
alternative 2. Many of the stands are existing even-aged forest structures. Application of the
alternative 2 proposed selection cutting treatments would fully achieve results number 1, 2,
and 3 above, and partially achieve result #4 (a full representation/balance of VSS classes is
not possible because the initial treatment would only begin the process of conversion from an
even-aged to uneven-aged condition).
Figure 9a. Uneven-aged stand, pre-treatment 2007.
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Figure 9b. Uneven-aged stand, post-treatment 2008.
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AREAS LESS 0.33 ACRE AREAS GREATER 0.33 ACRE
Figure 9c. Post-Treatment Created Regeneration Group Openings.
Count: 61
Minimum: 0.034
acre
Maximum: 0.282
acre
Sum: 8.50 acres
Mean: 0.13 acre
Count: 16
Minimum: 0.331
acre
Maximum: 1.392
acre
Sum: 8.76 acres
Mean: 0.548 acre
Total Stand Acres = 64.8
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Figure 10. Eagar South Goshawk PFA Management Area; Pre and Post Treatment.
Natural meadows and openings would be maintained by removing conifers which have
encroached upon these areas, post-European settlement. Quaking aspen and Gambel oak
patches would be released or favored to develop. Understory grasses, forbs and shrubs would
respond to these opened canopy conditions, and increase in abundance and vigor.
Management would focus on favoring and regeneration of Southwestern white pine in
locations where it currently exists.
Some effects of these treatments would be increased tree growth and favoring of the
dominant trees within groups. Groups or stands currently classified as VSS 3 would be
classed as VSS 4 and 5 post-treatment (resultant from favoring dominant trees for retention).
Increasing the percentage of acres in the VSS 4 class allows for a greater number of residual
trees for development into future VSS 5 and 6. These effects would occur in both the existing
even and uneven-aged structured stands.
Enhanced vegetative ground cover would also improve forest soil nutrient cycling and
stability (Dahms and Geils 1997). Forest regeneration is expected to occur within 5 years of
the broadcast burning treatment. Within 10 years these openings would become VSS 1 and 2
tree groups. Due to the moderately-sized regeneration canopy gaps that would be created
(average 0.33 to 0.75 acre), the site conditions would favor regeneration of shade intolerant
species in ponderosa pine and mixed conifer stands. Broadcast burning is expected to reduce
densities of the new regeneration but not eliminate it, due to the size of the canopy-free
openings which would moderate fire effects.
0
10
20
30
40
50
60
70
2 4 6 8 10 12 14 16 18 20 22 24 26 28
Tre
es
pe
r A
cre
Diameter in Inches
Eagar South Pre & Post Treatment Comparison
2007 Pre-treatment
2008 Post-treatment
Trees in the 2 and 4 inch classes exceed 70 trees per acre pre-treatment.
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Selected natural meadow locations would be maintained/restored to grassland or wet
meadow by removal of all conifer trees (except VSS 6 tree groups and yellow-pine
individuals).
Forest Structure – Mexican Spotted Owl
In MSO protected habitat forest areas, where thinning is restricted to cutting trees up to a
maximum 16 inches dbh, a reduction of excess density in understory trees would occur, but
overall forest canopy cover and continuity would remain unchanged. Effects on forest health
and vigor would be minimal as a result of these treatments, but minor improvements in the
ability to implement and control prescribed fire treatments would be realized due to the
reduction of ladder fuels.
In the recovery nest/roost habitat, broadcast burning appears to have dropped the minimum
BA for the one stand that is being thinned. Stand prescriptions however would be written to
meet the minimum BA requirement of 120 BA for mixed conifer. Basal area percentages
themselves do not change and are the same as alternative 1 and 3 (table 22). Alternative 2 is
the same as alternative 3.
Old Growth
Alternative 2 would exceed the forest plan percentages for old growth allocation within the
project area, and would move the total district acres towards meeting the percentages for
aspen, mixed species, and ponderosa pine as shown in tables 24 and 25. This alternative
proposes allocating 7,852 acres (table 24) with an existing large tree component and thinning
to improve forest health, increase tree size growth, and reduce fire hazard. Stands proposed
for thinning would develop towards old growth characteristics described in the forest plan,
over time.
Table 24. Allocated old growth displayed by alternative for the Larson project .
Old
Growth
Forest
Cover Type
Larson
Total
Acres
Alt. 1
Current
Old
Growth
Allocated
Acres
Alt. 1
Old
Growth
Percent
Allocated
Alt. 2 & 3
Proposed
Acres
Allocated
for Old
Growth
Alt. 2 & 3
Percent
Allocated
Desired
Allocation
Aspen 63 0 0% 20 32% >20%
Mixed
species
1,676 782 47% 1,282 76% >20%
Ponderosa
Pine
27,754 3,779 14% 6,550 24% >20%
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Table 25. Black Mesa District old growth allocation percentage including alternatives 2 and 3.
Old
Growth
Forest
Cover Type
Black
Mesa
District
Total
Acres
Alt. 1
District
Old
Growth
Allocated
Acres
Alt. 1
District
Old
Growth
Percent
Allocated
Alt. 2 & 3
District
Proposed
Additional
Acres
Alt. 2 & 3
District
Percent
Allocated
Desired
Allocation
per cover
type
Aspen 296 61 21% 20 27% >20%
Mixed
species
18,302 9,131 50% 9,913 54% >20%
Ponderosa
Pine
295,848 51,270 17% 55,049 19% >20%
Unknown 74,326 2,802 4% 0 4% >20%
Treatment Longevity
Based upon proposed irregular spacing and creation of regeneration group openings, forest
interspace, the uneven-aged forest character would persist for 30+ years following the initial
treatment and longer if low-severity fire occurs at frequent intervals. Trees 5 to 9 inches dbh
would develop interlocking crowns and closed forest canopy within the first one to two
decades following treatment (based upon residual density ranges and average growth rates,
Ronco et al. 1985); and tree groups in the 12 to 18 inch dbh range would remain closed
canopy following treatment (based on treatment objectives). Seedlings and saplings up to 5
inches dbh would not fully occupy the created canopy gaps or develop to a height
approaching the 2/3 of the general forest canopy until tree age 40-60 years, maintaining the
canopy gaps during this period. Also the forest interspace would be maintained for a like
period (indefinitely if low-severity fire occurs at frequent intervals). Therefore the desired
forest structure, biological diversity, and crown fire hazard reduction effects would be
evident for at least 30 years following the proposed treatment.
Alternative 2 Summary (and consistency with LRMP)
This alternative makes rapid progress in moving stand structures and other forest conditions
towards desired conditions, compared to no change in current conditions (alternative 1), and
much more effectively than alternative 3.
Achievement of the following forest plan and project purpose and need, vegetation
management objectives is feasible under alternative 2:
1) Restore historic forest spatial patterns; forest canopy gaps and openings on 20-40% of
each stand area (excluding MSO Protected and recovery nest/roost habitat, slopes greater
than 35%, and goshawk nesting areas). These canopy gaps and forest openings mimic
historic spatial patterns and provide for; regeneration of shade intolerant tree species,
development of grass/forbs and shrubs, rooting zones for tree group development, and
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facilitate re-introduction and maintenance of frequent surface fire as an ecological
process.
2) Maintain existing uneven-aged stands and progress towards a balance of VSS classes
by creation of sufficient regeneration canopy gap openings within goshawk habitat.
3) Convert existing even-aged stands to uneven-aged structure by creation of sufficient
regeneration canopy gap openings.
4) Achieve target stand density, while providing for maintenance and development of a
balance of VSS.
5) Fully address and manage forest health issues such as stand density, dwarf mistletoe,
forest genetics, and favoring development/regeneration of Southwestern white pine.
6) Manage mixed conifer stands to favor/regenerate forest species composition
commensurate with the desired conditions.
This alternative is consistent with the Apache-Sitgreaves National Forest Land Management
Plan (USDA 1987, as amended 2009) relative to forest vegetation management.
Alternative 3
Alternative 3 proposes to conduct commercial and non-commercial thinning using
mechanical equipment. This alternative proposes management of forest density by thinning
from below up to 16 inches dbh. Uneven-aged selection cutting to manage forest structure
would be implemented to the extent possible under the constraints imposed by this
alternative. MSO protected habitat stands would be treated the same under this alternative as
described for alternative 2. Approximately 9,394 acres would be managed to develop towards
forest plan old growth forest criteria, the same as for alternative 2. Additional broadcast burn
acres are proposed for this alternative because 721 acres of shelterwood treatments were
removed from this alternative and included in the burning only. Stands which would only be
broadcast burned or left untreated would be identical to alternative 2. Prescribed fire
treatment objectives would be the same as described for alternative 2, but effects may be
slightly greater due to a more closed canopy. Opportunities for timber or other biomass
products would occur, and costs would be incurred for thinning and burning treatments under
alternative 3. Table 23 displays a comparison of treatment acres by forest stratum. See the
silvicultural prescription details in appendix B.
Direct and Indirect Effects
Forest Health
Alternative 3 moves the treated areas towards healthier forest conditions by restoring more
vigorous growth conditions, and reducing losses due to tree mortality, wildfires, insects and
diseases, relative to alternative 1. Alternative 3 would be slightly less effective than
alternative 2 for increasing forest health and vigor, unevenaged stand conditions, and forest
resiliency to stresses such as insects, disease, and climatic variability.
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Stand Density
Stand densities would be reduced in all of the harvest units, but the ability to reduce densities
to desired conditions would be limited by the 16 inch diameter cutting constraint, and some
stands or areas would not achieve desired density objectives (see figure 13 example). Based
upon all forest stands (treated and untreated) 80% of northern goshawk habitat forest types
(by area) and 75% of MSO restricted (other) habitat forest types (by area) are projected to
meet desired maximum density conditions post-treatment (table 4 and appendix A). Overall
stratum-level statistical differences in stand density are slight relative to alternative 2.
Insects and Disease
This alternative is almost as effective as alternative 2 for reducing bark beetle hazard because
overall BA is reduced; however the creation of more even-aged larger tree sizes lends itself
to bark beetles that prefer even-aged stand conditions (table 17). In 2020, approximately
72% of the analysis area would be in the low hazard category (table 14). On 28 % of the
analysis area beetle hazard remains high due to stands which would not receive mechanical
treatments to reduce forest canopy. In these areas stand density would not be reduced
enough to effect bark beetle hazard.
Dwarf mistletoe management treatments proposed under this alternative are the same as
described for alternative 2, with the added constraints of the 16 inch diameter cap limitation.
As a result of these constraints, alternative 3 is less effective than alternative 2 for
management of dwarf mistletoe and leaves the worst infections in the stands because the
greatest infections are in the larger trees which are overtopping the younger tree groups in the
stands. Individual tree DM ratings would be lower than alternative 1 for the smaller trees
and the same for trees 16 dbh inches and larger. Cone production would be much lower than
alternative 2 because the larger cone producing trees with high DM ratings would be left in
the overstory (table 6).
Alternative 3 would provide some opportunities to manage dwarf mistletoe severity,
incidence, and distribution, but management opportunities would be more limited than
alternative 2. Treatments would alternately focus on removal of infected trees (less than 16
inch dbh) in locations where new regeneration openings (VSS 1-2) would be established or
favored, and reduction of the percentage of severely infected trees (less than 16 inch dbh)
elsewhere within the stands. However, the effects of this constraint greatly reduce the ability
to create regeneration openings and forest interspace (see figures 11 & 12), thereby
maintaining high continuity of mistletoe occurrence, spread, and effects in most currently-
infected stands. This continuity greatly limits opportunities to manage for characteristic
dwarf mistletoe distribution patterns and effects, and would maintain current uncharacteristic
conditions, albeit at a less severe level than alternative 1. The focus would be on managing
dwarf mistletoe locations, severity and spread potential to the extent possible under the tree
size cutting constraint. In many cases the constraints of this alternative would result in
favoring diseased trees/species over non-infected trees/species in order to balance the trade-
off of stand density objectives over forest health objectives.
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Mistletoe often increases in the understory trees when thinning occurs and dwarf mistletoe is
not removed from the overstory trees (Hawksworth and Weins 1996). Thinning from below
would leave mistletoe in the larger trees allowing them to infect regeneration which would
establish after treatment. This alternative would limit the ability to manage for desired
uneven-aged forest conditions, and over time (2 to 4 decades) would limit sustainability of
uneven-aged stands where current infection levels exceed 25% of host trees, over 73% of the
analysis area (table 21). It would also severely limit the ability to convert existing diseased
even-aged stands to uneven-aged stands. Trees with severe dwarf mistletoe infection levels
exhibit low vigor overall, and these trees are more susceptible to bark beetle and density-
induced mortality.
This alternative provides some limited opportunities to manage for maintenance or
improvement of forest genetics within the project area. In many locations within the project
area, historic high-grade cutting has resulted in mature trees with “poor-formed” and stunted
characteristics, relative to the original genetic diversity that existed prior to the cutting. Many
of these genetically-stunted trees do not develop into VSS 6 forest structural stages or large
individual trees, even at advanced ages. Therefore, most of these trees remain small in size
relative to age, and neither these trees nor their progeny develop desirable mature forest
habitat characteristics. In some locations, it would be advantageous to remove these
individual “poor-formed” trees to favor seed trees with more desirable and “normal-formed”
traits. On a case-by-case basis, alternative 3 permits the favoring of seed trees with desirable
growth traits over those remnant examples of the poorest-formed individuals left from the
original forest stands, if the poor-formed trees are less than 16 inch dbh. In areas where group
selection is utilized, selection for the removal groups may be difficult because of the 16 inch
dbh limit and the best trees may not always be chosen for retention as seed trees. This may
even result in genetically inferior trees being retained (UOM 1995). Where phenotypically
undesirable trees are greater than 16 inch dbh, these trees would remain to provide the
regeneration seed source for the future.
Forest Structure
Structural objectives would not be achieved because it is often difficult to create and place
sufficiently-sized openings when silvicultural prescriptions are constrained by a tree size
limit (Abella et al. 2006). It is very likely that alternative 2 would result in much fewer
canopy gaps/openings of sufficient size to achieve objectives than alternative 2 on 70% of
the project area (55% uneven-aged forest, 15% mature even-aged forest, goshawk + MSO
restricted habitats).
The forest vegetation spatial patterns would be different under this alternative than under
alternative 2. The post-treatment tree distribution would be more uniform leading to more
rapid canopy closure (5 to 15 years) of the forest as it develops post-treatment. Research has
shown that diameter constraints maintain more tree canopy and result in more rapid in-
growth of the canopy following treatments (Abella et al. 2006). The constraints of this
alternative reduce opportunities to restore historic forest spatial patterns including
regeneration openings and forest interspace (excluding MSO protected and recovery
nest/roost, and goshawk nesting areas).
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Forest Structure - Goshawk
Alternative 3 moves forested vegetation conditions for goshawk closer to the desired
conditions than alternatives 1. In 2035, VSS 3 and 4 are deficit while VSS 5 and 6 represent
70% of the landscape. In 2035 the desired conditions for VSS distribution would not be met
and stands would be considered even-aged. Graphs 1 and 2 display alternative 3 moving
away from the desired VSS classes with less improvement in the VSS 6 classes than
alternative 2 and becoming unbalanced for the FA. Alternative 3 would have a greater
percentage in the VSS 4, 5, and 6 in the PFA (graphs 3 and 4) but lacking in the VSS 3 due to
thinning from below to 16 inches dbh.
Failure to achieve regeneration/development openings over 20% of the area results in the
inability to implement the uneven-aged management strategy required by forest plan
direction. Sustainability of uneven-aged forest characteristics cannot be achieved without
effective creation of proportional regeneration areas. Over time, these conditions would
result in domination of the site by the overstory trees, effectively creating or maintaining a
functional even-aged, closed-forest condition displayed in table 17. Additionally, failure to
develop and restore forest openings would limit attainment of other ecological objectives,
such as improving biological diversity and re-initiation of frequent surface fire.
Relevant examples were examined to determine expected outcome effects of alternative 3.
Two treatment areas on the Apache-Sitgreaves NFs were recently treated with the same 16-
inch dbh limit cutting prescription constraint (Black Mesa RD, Little Springs Treatment Area
(figures 10a-c); Springerville RD, Mineral Treatment Area (figures 11a-c, and Hurteau
2010). These areas were selected as representative of forest stands and probable treatment
outcomes within the Larson project area for the following reasons:
1) The Mineral project area was a closed-canopy, mature two-storied stand (VSS 3-4
dominant with VSS 2 intermixed) prior to treatment. This is typical of those stands
classed as even-aged12
in the Larson area (see the Wildlife Specialist Report). A 16”
diameter limitation in these stands would severely limit the ability to implement uneven-
aged group selection treatments.
2) The Little Springs project area is adjacent to the project and prior to treatment was
classed as a closed canopy, uneven-aged stand (3 or more age classes represented). This
forest condition represents approximately 90% of all forest lands within the project area
(excluding MSO habitat) .
12
One and two-storied stands are commonly classified as “even-aged” forest structure.
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Pre and post-treatment aerial photography was analyzed to calculate the canopy openings
created under the constraints of this treatment. On the Little Springs Treatment area,
regeneration/release openings (greater than 0.33 acre) were created on 8% of the treated area.
On the Mineral Treatment area, openings were created on less than 1% of the treated area
and none of the openings created were greater than 0.33 acre in size. See Hurteau 2010 for
comparative analysis conducted by The Nature Conservancy. Creation of regeneration group
openings over 20% of the area was not achievable on either example treatment area, due to
the constraints of the maximum tree size cutting limitation. Neither the regeneration canopy
gap objectives, nor the other forest opening objectives were achieved
(desired objectives = 20-40 forest openings overall).
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Figure 11a. Uneven-aged Stand, pre-treatment, 2000.
Figure 11b. Mature even-aged (functional) stand, post-treatment, 2008.
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AREAS LESS 0.33 ACRE AREAS GREATER 0.33 ACRE
Figure 11c. Post-Treatment Created Regeneration Group Openings.
Count: 133
Minimum: 0.041 acre
Maximum: 0.328 acre
Sum: 20.39 acres
Mean: 0.15 acre
Count: 31
Minimum: 0.331 acre
Maximum: 1.14 acre
Sum: 15.95 acres
Mean: 0.51 acre
Total Stand Acres = 193.9
Figure 12a. Mature even-aged stand, pre-treatment, 2000
Figure 12b. Mature even-aged stand, post-treatment, 2007
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AREAS LESS 0.33 ACRE
Figure 12c. Post-Treatment Created Regeneration Group Openings
Total Stand Acres = 33.7
Count: 13
Minimum: 0.064 acre
Maximum: 0.225 acre
Sum: 1.17 acres
Mean: 0.19 acre
Count: areas > 0.33 = 0
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This alternative would result in the greatest increase in the VSS 5 class but moves stands
toward even-aged stand conditions because so many small and mid-sized trees would be
removed in order to lower the tree density to meet some fuels reduction objectives. Because
a 16 inch dbh limit would result in the retention of the larger trees, more small trees would
need to be removed to meet desired residual density levels and those that remain would need
to compete for resources with these larger trees. A deficit of small trees (VSS 1 and 2 )
would occur due to the intensive thinning of small tree structural stages, necessary in order to
balance the trade-off of stand density objectives over forest structure objectives. (See
example treatment area summaries: Pre and Post Treatment Stand Conditions: Black Mesa
RD, Little Springs Treatment Area (figure 12); and Pre and Post Treatment Stand Conditions:
Springerville RD, Mineral Treatment Area (figure 13). The deficit in small trees created by
this treatment would be further exacerbated by the lack of opportunities to create
regeneration development canopy gaps, as previously discussed. Also, remaining VSS1 and 2
size/age classes would stagnate and would not develop over time, due to the effects of
uniform forest over-story without gaps. This creates a functional even-aged stand, despite
the limited presence of some age class diversity.
Figure 13. Little Springs Treatment Area; Pre and Post Treatment Stand Conditions.
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
0 - 3.9 4 - 7.9
8 - 11.9
12 - 15.9
16 - 19.9
20 - 23.9
24 - 27.9
28 - 31.9
32 - 35.9
36 - 39.9
Tre
es
pe
r A
cre
(TP
A)
Diameter Classess in Inches
Pre & Post Treatment Comparison
Pre-treatment TPA
Post-treatment TPA
Post-treatment basal area ≈ 90 ft2
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Figure 14. Mineral Treatment Area; Pre and Post Treatment Stand Conditions
3) Northern Arizona University, Ecological Restoration Institute (NAU-ERI) study example
(Tuten 2006).
4) The Nature Conservancy Forest Restoration study example (Hurteau 2010).
Alternative 3 would limit opportunities to manage for desirable species composition in the
mixed conifer forest type. In many cases, the 16 inch diameter constraint would require that
less desirable shade tolerant species be retained in place of highly desirable species such as
Southwestern white pine in order to balance the trade-off of stand density objectives over
species composition objectives.
Creation of openings for aspen and oak regeneration would be more limited or not created
due to the project constraints, therefore these species would continue to decline in abundance
and vigor. The stands that are being treated for meadow enhancement would have a decrease
in tree cover but less so than alternative 2. Regeneration is expected to occur within 5 years
of the broadcast burning treatment, but since the openings are smaller (average less than 0.33
acre) than under alternative 2, regeneration of shade intolerant species in ponderosa pine and
mixed conifer stands would be less vigorous and limited in distribution. In mixed conifer
stands, regeneration would be dominated by shade tolerant species such as white fir.
Broadcast burning is expected to greatly reduce densities of the new regeneration, and where
regeneration openings are small may eliminate it.
Selected natural meadow locations would be partially maintained or restored to grassland or
wet meadow by removal of all conifer trees less than 16 inch dbh.
0
20
40
60
80
100
2 4 6 8 10 12 14 16 18 20
Tre
es
pe
r A
cre
Diameter Classes in Inches
Mineral Pre & Post Treatment Comparison
Pre-treatment
Post-treatment
Post-treatment basal area ≈ 50-60 ft.2
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Alternative 3 is less effective than alternative 2 in providing forest resiliency to climatic
variability and other environmental stressors, but greater than alternative 1. This alternative
limits management of stands toward uneven-aged conditions (on much of the area), thereby
limiting improvement of forest health and tree resilience. Tree growth would increase
through thinning and would sequester slightly more carbon than alternatives 1 and 2. This
alternative provides opportunities for renewable products such as lumber and biomass
energy.
Forest Structure -MSO
In MSO protected habitat forest areas, where thinning is restricted to cutting trees up to a
maximum 16 inches dbh, a reduction of excess density in understory trees would occur, but
overall forest canopy cover and continuity would remain unchanged. Effects on forest health
and vigor would be minimal as a result of these treatments, but minor improvements in the
ability to implement and control prescribed fire treatments would be realized due to the
reduction of ladder fuels.
In the recovery nest/roost habitat, broadcast burning appears to have dropped the minimum
BA for the one stand that is being thinned. Stand prescriptions however would be written to
meet the minimum BA requirement of 120 BA for mixed conifer. Basal area percentages
themselves do not change and are the same as alternative 1 and 2 (table 22).
Old Growth
Alternative 3 would allocate the same amount of area for old growth management as
alternative 2 (table 24 and 25).
Treatment Longevity
Due to the small size of created openings and the current spacing of trees greater than 16
inches dbh most treated areas within the project area would quickly develop interlocking or
nearly interlocking crowns within a relatively short time span following this treatment (less
than 10 years), based on resulting density and average growth rates (Ronco et al. 1985).
Continuous interlocking crown conditions inhibit regeneration, growth and vigor, reduce
biological diversity, and greatly increase crown fire potential. Additional treatments would
need to be considered within 10 years to reduce fire hazard as a result of the interlocking
canopy of trees. These treatments would need to include the removal of trees 16 inches dbh
and larger which contribute to the interlocking canopy.
Alternative Summary (and consistency with forest plan)
This alternative would result in many post-treatment stands with a higher density of trees 16
inches and larger, therefore; lower resistance to bark beetles, and lower forest resiliency to
climate change than alternative 2. There would be fewer openings in the canopy than in
alternative 2. The effects of these constraints would limit the development/maintenance of
forest interspace to less than 10% of the area, reducing development/favoring of deficit VSS
1 and VSS 2 classes, compared to alternative 2. Fire hazard would be less than alternative 1,
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but greater than alternative 2 due to fewer gaps in the canopy and forest openings. Selection
for the removal groups may be difficult and the best trees may not always be chosen for
retention as seed trees; this may even result in the retention of genetically inferior trees, while
smaller genetically superior trees are removed to meet objectives for stand density and fire
reduction. In the short term, a deficit of small trees in the VSS 1 and VSS 2 would occur due
to intensive thinning in these structural stages. In the long-term this would result in a deficit
of mid-aged and mature trees. Growth of the larger trees would be greater than alternative 1
due to the reduction in stand density but less than alternative 2. Trees severely infected with
mistletoe would be favored over healthier smaller trees based on size alone, and the overall
severity and continuity of dwarf mistletoe infection would be less than alternative 1, but
significantly greater than alternative 2.
This alternative makes some progress in moving some stand structures and other forest
conditions towards desired conditions, compared to no change in current conditions
(alternative 1), but is much less effective than alternative 2. In some areas within the project
area, implementation of this alternative would result in attainment of objectives (primarily
where immature even-aged stands currently exist); while in other locations objectives would
not be obtained.
Achievement of the following forest plan and project purpose and need vegetation
management objectives are feasible under alternative 3:
1) Achieve target stand density in most treated stands.
2) Reduce bark beetle hazard in most treated stands.
3) Partially reduce and manage dwarf mistletoe severity and extent in some stands.
4) Partially achieve desired stand structure and species composition in some stands.
Immature even-aged stands (VSS 1-2-3) of forested area (goshawk + MSO habitats): in
these areas, constraints seldom limit attainment of age/size/density objectives (may have
minor effects on meeting forest health/species objectives). Few trees larger than 16” dbh
exist in these stands, and those that occur would be retained to add necessary structural
diversity, and as seed trees to facilitate regeneration treatments to recruit a new age class
cohort.
Based upon past examples where this alternative was implemented in other locations on the
Apache-Sitgreaves NFs, implementation of this alternative in existing uneven-aged stands
would result in homogenization of forest structure such that stands would become single or
two-aged after treatment, and existing even-aged stands would be maintained in even-aged
condition. In many locations, the constraints of this alternative would limit opportunities to
create effective regeneration treatments, hindering options to create and maintain uneven-
aged forest structure, therefore:
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The following forest plan requirements and project purpose and need vegetation management
objectives would be constrained, or would not be met under alternative 3:
1) Restore historic forest spatial patterns; forest canopy gaps and openings on 20-40% of
each stand area (excluding MSO protected and recovery nest/roost habitat , and goshawk
nesting areas). These canopy gaps and forest interspaces mimic historic spatial patterns
and provide for; regeneration of shade intolerant tree species, development of grass-forb-
shrub component, rooting zones for tree group development, and facilitate re-introduction
and maintenance of frequent surface fire as an ecological process.
(Achievement of this objective would not occur or be limited in many stands under
the constraints of this alternative.)
Constraints limit creation of sufficient regeneration group openings to maintain
all-aged structure
Constraints force a trade-off between forest structure and density. Uneven-aged
forest structure is reduced or lost to meet density objectives (treated stands move
towards even-aged structure)
Constraints limit creation of sufficient regeneration group openings to initiate
conversion of even-aged stands to all-aged structure
Constraints force a trade-off between forest structure and density. Forest age/size
class distribution is reduced or lost to meet density objectives
Cumulative Effects Common to all Alternatives
Past, present (ongoing), and reasonably foreseeable future actions that have occurred over the
last 10 years within the project area were evaluated are displayed in table 26.
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Table 26. Cumulative effects common to all alternatives.
Past and present
activity
Timeframe Location Comments
Rodeo-Chediski Fire
Salvage Project
2005 Black Mesa RD 1,700 acres of salvage removal
and piling.
Rim Top prescribed
burn
2005 Black Mesa RD
(adjacent to project
area)
300 acres of prescribed fire.
Forest Lakes WUI
Treatment area
2005 – 2007 Private land adjacent
to the project area
1700 acres of thinning, piling,
and burning adjacent to the
Forest Lakes community,
within the WUI.
High value ponderosa
pine tree protection
2005 – 2008 Black Mesa RD
(adjacent to project
area)
Within developed recreation
sites across the district
thinning, piling, burning, and
application of cabaryl occurred
to reduce bark beetle attacks.
About 700 acres treated in
total.
Hidden Lake broadcast
burn
2005 – 2009 Black Mesa RD
(within project area)
900 acres of broadcast burning.
Jersey Horse Timber
Sale
2005 – 2011 Black Mesa RD
(adjacent to project
area)
500 acres of thinning, piling,
and burning.
Little Springs Wildland
Interface project
2006 – 2009 Black Mesa RD
(adjacent and within
project area)
Thinning of 3,300 acres
adjacent to project area;
thinning of 50 acres within
project area.
Nagel Forest Health
Project
2006 – Ongoing Black Mesa RD Thinning, piling, and broadcast
burning on 250 acres.
Hazard tree removal 2006 – 2012 Black Mesa RD 300 acres of hazardous tree
removal in the WUI and along
state highway 260.
Brookbank multi-
product timber sale
2007 – 2010 Black Mesa RD
(adjacent to project
area)
60 acres of mechanical
thinning with removal of fuels
by piling and yarding.
Chevelon complex fire
2009 Black Mesa RD
(adjacent to project
area)
13,400 acre wildfire adjacent
to the project area.
Bruno thinning and
slash treatment
2010 – 2011 Black Mesa RD
(adjacent to project
area)
Piling and burning of forest
material on 70 acres.
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Table 26. Continued
Rim Lakes Forest
Restoration
2013 – present Black Mesa RD 25,000 acres authorized for
treatments – thinning to start in
2015.
SRP/APS power line
mastication
On-going Black Mesa RD
(within project area)
Removal and mastication of
trees every five years
encroaching on the power line
corridor.
Grazing On-going Black Mesa RD
(within and adjacent
to the project area)
Portions of three allotments
cover the project area. Long
Tom allotment overlaps 28,435
acres of the project area (96%),
while Heber allotment overlaps
458 acres (1%) and Wildcat
allotment overlaps with 855
acres (3%).
Road maintenance On-going Black Mesa RD Routine road maintenance on
already existing roads across
the district.
Dispersed camping On-going Black Mesa RD
(within and adjacent
to project area)
The project area contains
locations popular for dispersed
camping.
Forest Lakes brush pit On-going Black Mesa RD Community brush pit near the
project area where residents
can dispose of brush. Brush is
either burned or chipped.
Forest Lakes
community thinning
and road maintenance
On-going Private land adjacent
to project area.
On-going thinning on small
private lots, tree removal for
home construction, and routine
road maintenance
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Past Actions
The past activities that have influenced vegetation described in the affected environment
section are found on page 8 and activities. Activities include timber sales, pre-commercial
thinning, salvage sales and broadcast burning occurring within the boundary of the project
area and were used in the vegetation cumulative effects. Existing stand densities are
displayed in table 4 and existing forest structures displayed in tables 5, 7, 8, and 9 are an
expression of the cumulative effects of past vegetation modifying treatments as well as
wildfires, even though wildfires are not actions considered in cumulative effects. Wildfires
do have an effect on the current condition of the area. Past activities and wildfires that
modified vegetation contributed to that VSS distribution and to the stand density percentages.
On-going present actions
Portions of three allotments cover the project area. The Long Tom Allotment overlaps 28,435
acres of the project area (96%), while the Heber Allotment overlaps 458 acres (1%) and the
Wildcat Allotment overlaps with 855 acres (3%).
The Long Tom Allotment is grazed by sheep for approximately 6 months of the year. Sheep
grazing is monitored for utilization and pastures rested and rotated for recovery. The
Limestone Allotment has not been grazed by cattle for the past 15 years and grazing is not
anticipated in the near future. Grazing was considered and determined to have no cumulative
effect on forest health and structure.
Any tree removal within campgrounds, along State Highway 260, and along forest service
roads is limited to imminent hazards from dead, dying and defective trees, which is not a
significant change to the overall structure and composition of the area impacted and has been
determined to have no measureable cumulative effect.
Future Actions
Future actions within the project area include mastication of trees within the powerline
corridor of approximately every 5 years.
The effects of alternative 1, 2, or 3 when combined with the foreseeable treatments would not
provide measurable cumulative effects. The mastication of trees within the powerline
corridor is very limited in size (less than .02% of the analysis area) and the powerlines are
continually maintained as openings by both the Salt River Project and Arizona Public Service
on 5 year intervals and were considered as grassland maintenance.
Climate Change
All background information on climate change is from Malmsheimer et al. (2008) unless
otherwise noted. Climate shapes our forests and forests shape our climate. The Larson
project is proposed on a local scale and is not intended to have cumulative effects that are
measurable on a global scale in regards to climate change; however, management of the
Larson area has a small scale effect on mitigating climate change when combined with other
management actions regionally. Ninety-eight percent of the Larson project is currently
considered overstocked (table 4) and at risk for stand-replacing fires which are the greatest
Larson Forest Restoration Project Silviculture Specialist Report
July 30, 2014 Page 67 of 67
cause of carbon release or greenhouse gases (GHG). Both alternatives 2 and 3 reduce the fire
hazard within the project area associated with stand-replacing fires.