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REGENERATION UNDER PARTIAL REGENERATION UNDER PARTIAL CUTTING FOR PROGNOSISCUTTING FOR PROGNOSISBCBC, ,
MSdk Subzone, MSdk Subzone, CRANBROOK FOREST DISTRICT CRANBROOK FOREST DISTRICT
Badre Tameme Hassani, M.Sc.,
Valerie LeMay, PhD., RPF, Peter Marshall,
PhD., RPF and Abdel-Azim Zumrawi, PhD., RPF
Presented at the Cranbrook District Office
November 6, 2002
Background• Understanding stand dynamics is necessary to achieve
management objectives• MoF has adopted PrognosisBC to predict the dynamics of
complex stands in the southern interior of BC• PrognosisBC is an adaptation of the US Forest Vegetation
Simulator (FVS); it forecasts future stand conditions based on the expected growth and mortality of individual trees
• It can be used to simulate a wide variety of stand management activities, including any form of harvesting
• PrognosisBC has been calibrated by the MoF, in conjuntion with the Faculty of Forestry at UBC, for use in southeastern BC since 1997
• It has been calibrated for use in several BEC subzones/variants in the Kamloops, Nelson, and Cariboo Forest Regions
• Calibration of large tree (height and diameter), live crown ratio, and mortality was done using PSP data
• Insufficient data limited the capability of the model to predict small tree height growth, regeneration, and to make long-term projections following harvesting
• Currently, the regeneration portion of PrognosisBC has been disabled; users must supply their own data
• Regression approaches did not lead to good predictions of regeneration
• Predicting the regeneration of complex stands in the ICH using imputation approaches proved to work better than regression
Objective
• Predict regeneration under partial cutting using the tabular imputation approach for complex stands in the MSdk subzone
Outline
• Location of the study area
• Methods
• Results
• Conclusions
• Current and future projects
Location of Study Area in BC
• Continental climate
• Middle elev. (1100-1650 m)
• Bounded by IDF (lower elev.) and ESSF (higher)
• Supports 11 trees species
Nelson Forest Region
Complex Stands in the MSdk zone
• Mixed species
• Uneven-aged
• Multi-cohort
• Subalpine fir and hybrid spruce are climax species
• Extensive presence of lodgepole pine and Douglas-fir
Potential PolygonsGroup (yrs)
CCRes CC Patch Seed-tree
Shelter-wood
Selection Missing*
1 (1-5) 38 5 6 5 3 0 2
2 (6-10) 51 81 4 81 10 21 0
3 (11-15) 1 37 0 33 0 11 1
4 (16-20) 5 13 0 59 0 11 2
5 (21-25) 3 42 0 48 0 10 0
* missing information on the silvicultural system
Plot Layout• Nested plots
• Systematically located in
selected stands
• Stands selected to cover the range of: overstory density age since disturbance site preparation slope percent aspect elevation
• 122 plots from 52 polygons
STP(3.99m)
LTP(=11.28 m)
Regen. P(2.07m) Satel. P
(2.07m)
Species Groups
Species Group Species
Shade tolerant Cedar, subalpine fir, spruce
Shade semi-tolerant Douglas-fir
Shade intolerant Larch, lodgepole pine
Hardwood Aspen, cottonwood, Douglas Maple, willow
Tabular Imputation Methods
Stand Conditions
• Basal Area class: Dense: > 5m2/ha; Open: =< 5m2/ha
• Site Series class: Dry: 02, 03, and 04 Wet: 01, 05
• Time-Since-Disturbance Group (years): Group 1: 1-8 2: 8-16 3: 16-25
Tabular Imputation Approach
For each stand condition combination: • Average number of seedlings per ha by:
height class (1: 15-49.9 cm for shade tolerant species and 30-49.9 cm for shade intolerant species, 2: 50-99.9 cm,
3: 100-129.9 cm, and 4: >130 cm) and for the 4 species groups (16 regeneration variables)
Precision of the tabular imputation modelsStandard error of the mean for each cell of in the tables
Results
Sampling and Regeneration Composition• 12 undisturbed, 13 clear-cut plots from 122 plots
• 69% of the plots were site series 04
• Overstory dominated by intolerant species (819 stems/ha)
Yrs since Disturbance
Yr # plots
0 12
5 6
5-10 41
10-15 15
15-20 22
>20 26
Site Series
SS # plot
02 2
03 9
04 84
01 23
05 4
Residual BA (m2/ha)
Meth # plot
0 8
1-5 40
5-10 26
10-15 14
15-20 9
20-25 5
25-30 5
30-35 4
35-40 2
>40 9
Silv. System
Method # plot
CC 13
CC/Res 15
Light shelter 2
Seedtree 42
Selection 23
Shelter/Selec 3
Shelter/ST 1
Shelter 11
Undisturbed 12
Elevation- 100m
Elev. # plot
<=900 0
9-10 6
10-11 8
11-12 30
12-13 25
13-14 20
14-15 26
15-16 7
Site Prep.
Method # plot
None 81
Burn 41
Aspect
Aspect # plot
E 19
F 15
N 7
NE 15
NW 16
S 6
SE 17
SW 6
W 21
Slope Position
Position # plot
Crest 1
Lower 10
Ridge 1
Middle 76
Plateau 18
Terrace 8
Flat 4
Upper 4
Slope Percent
Slope # plot
0-10 39
10-20 38
20-30 21
30-40 9
40-50 6
50-60 6
>60 3
Diameter Distribution for all residual species combined
0
100
200
300
400
500
600
700
2.5 7.5 12.5 17.5 22.5 27.5 32.5 37.5 42.5 47.5 52.5 57.5 62.5
5-diameter class midpoint
Av
era
ge
Ste
ms
/ha
Regeneration Composition
• Average regeneration (over 122 plots)= 6023 seedlings/ha
• Averages of 2168, 1522, 1285, and 1048 seedlings/ha for shade intolerant, hardwood, semi-tolerant, and tolerant species respectively
• 29 plots had no regeneration (zero)
Regeneration by Site Preparation Treatment
9242
4394
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
Ave
rage
reg
ener
atio
n/ha
Burning None
Regeneration by Time-Since-Disturbance Groups
0
200
400
600
800
1000
1200
Avera
ge reg
enerat
ion/ha
Group 1 Group 2 Group 3
Time-since-disturbance group
Tolerant Semi-tolerant Hardwood Intolerant
1230
2576
2217
0
500
1000
1500
2000
2500
3000
Aver
age r
egen
erat
ion/h
a
Time-since-disturbance group
Group1 Group2 Group3
Tabular Imputation Models
12 tables were produced for the disturbed sites; 1 table for undisturbed sites
Dense, Dry, first 5 years since disturbance (n=7)
Species Height (cm) All heights
15-49.9 50-99.9 100-129.2 >130
Tolerant 0 0 0 0 0
Semi-tolerant 531 0 0 0 531
Intolerant 849 1168 0 106 2123
Hardwood 212 531 955 955 2653
All species 1592 1699 955 1061 53075307
Undisturbed Sites (n=12)
Species Height (cm) All heights
15-49.9 50-99.9 100-129.2 >130
Tolerant 743 62 0 0 805
Semi-tolerant 743 248 124 557 1672
Intolerant 0 0 0 124 124
Hardwood 0 0 0 0 0
All species 1486 310 124 681 26012601
SEM- disturbed sites: dense, dry, 5 yrs (n=7)
Species Height (cm) All heights
15-49.9 50-99.9 100-129.2 >130
Tolerant 0 0 0 0 0
Semi-tolerant 352 0 0 0 352
Intolerant 498 943 0 106 1636
Hardwood 137 420 738 955 1699
All species 524 927 738 943 20792079
SEM- undisturbed sites (n=12)
Species Height (cm) All heights
15-49.9 50-99.9 100-129.2 >130
Tolerant 419 62 0 0 461
Semi-tolerant 419 190 83 557 787
Intolerant 0 0 0 124 124
Hardwood 0 0 0 0 0
All species 593 193 83 681 930930
• Predictions based on three or less plots resulted in very high SEM (reaching 100 % of the mean in most cases)
• Predictions based on more than 10 plots had lower SEM
• Lowest SEM values were observed within tables based on more than 20 plots
Conclusions• Species composition of the overstory was dominated
by intolerant species followed by semi-tolerant species
• Treated sites had more regeneration than undisturbed sites
• Regeneration present on the disturbed sites were predominately comprised of seral species (intolerant and hardwood species)
• Regeneration was most abundant between 8 and 16 years after disturbance
• Shade tolerant and semi-tolerant species dominated undisturbed sites
• The tabular imputation approach made good use of the available data
• Tabular imputation models had a simple structure and provided detailed average post-harvest regeneration for different conditions
• Performance of this technique depends implicitly on the data used for the analysis
• These models are flexible and can be easily updated as more data become available
Acknowledgments
• This research was funded by Forestry Innovative Investment. In-kind support was provided by the BC Ministry of Forests, Research and Forest Practices Branches, UBC Faculty of Forestry, Tembec Industries, Riverside Forest Products, and Slocan Forest Products
Contact and Web Site
For more information, you can contact:• MoF Research Branch: Dr. Abdel-Azim Zumrawi
• UBC: Dr. Valerie LeMay and Dr. Peter Marshall
Web Site (for contact information and reports):• www.forestry.ubc.ca/Prognosis
• The final report will be available on the web by the end of November 2002
Work on progress:• Calibration of the PrognosisBC small tree height increment
model and development of regeneration imputation models for IDFdm2 in the vicinity of Invermere
Planned work:• Workshop at UBC to discuss future regeneration modelling
approaches (link of regeneration imputation techniques to PrognosisBC)
• Make the results accessible for users through the web• Consolidate the data collected over the past 5 years in
different zones into a single database (corporate database) for use and preservation
Current and Future Projects
Question for the Audience
• What other purposes could the data be used for?