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SilvoPasture with Hybrid SilvoPasture with Hybrid Poplar and SheepPoplar and Sheep
GreenWood Resources
Columbia Tree Farm
Clatskanie, Oregon
GreenWood Resources, Inc.GreenWood Resources, Inc.
Natural resource management company established in 1996, based in Portland, Oregon
GreenWood Resources, Inc.GreenWood Resources, Inc.
Currently manage nearly 15,000 acres of hybrid poplar plantations
6,000 acres west of theCascade Mountains
8,700 acres east of theCascade Mountains
GreenWood Resources, Inc.GreenWood Resources, Inc.
World-wide development and management of poplar plantations
Development of elite hybrid poplar and cottonwood genotypes
ChinaChina
ChileChileNew ZealandNew Zealand
FranceFrance
JapanJapan
N. AmericaN. America
What is Hybrid Poplar?What is Hybrid Poplar?
Crosses between Populus species– Black cottonwood
(P. trichocarpa)– Eastern cottonwood
(P. deltoides)– Japanese poplar
(P. maximowiczii)– European black
poplar (P. nigra)
Creating Hybrid PoplarsCreating Hybrid Poplars
Traditional hybridization through controlled pollination, propagation and testing of progeny
Uses of Hybrid PoplarUses of Hybrid Poplar
Wood products including veneer & lumber
Photo courtesy of British Columbia Ministry of Forestry and Lands
Uses of Hybrid PoplarUses of Hybrid Poplar
Feedstock for energy industry; co-firing with coal and liquid fuels
Uses of Hybrid PoplarUses of Hybrid Poplar
Land application of municipal effluent Phytoremediation of industrial sites and waste
water treatment
The Columbia Tree Farm (CTF)The Columbia Tree Farm (CTF)
Initially created to support area pulp andpaper mills
The Columbia Tree Farm (CTF)The Columbia Tree Farm (CTF)
Operate as agriculture, employing many conventional farm practices and equipment
Characteristics of the CTFCharacteristics of the CTF
Soils are loams to silty loams with high organic matter, low clay content
Excellent soil nutrient capacity Moderate temperatures throughout the year Rainfall up to 45” annually, primarily in the late
fall, winter and spring Plantations were initially planted with 600 to
900 trees-per-acre for rotations of 6 to 8 years
CTF Management StrategyCTF Management Strategy
Became independent of paper company in December, 2000
Free to pursue highest value markets for wood products
Transition to:– Longer rotations, 12 to 15 years– Wider spacing, density of 300 trees per acre– Pruning in sequential lifts to produce clear lumber – Larger piece sizes to maximize board-foot yields
Challenges at the CTFChallenges at the CTF
Longer period of weed control– Four versus two years– Mechanical and chemical
control– Increased cultivation
expense Increased potential for
damage from voles where vegetation creates good habitat
Purpose of SilvoPasture TrialPurpose of SilvoPasture Trial
Explore the range of plantation ages and stock types where sheep grazing could take place without injurious effects
Demonstrate benefits to plantation management and sheep ranching
To see if sheep grazing can be an effectivemeans of weed control in wider spaced plantations
Test SitesTest Sites
Thirty-six-tree plots were established inside and outside of each grazing plot for evaluation and comparison of tree growth and performance
Fenced grazing plot
ControlGrazed
Preparation of Test PlotsPreparation of Test Plots
Sowed cover crop in April, 2004
– Disked between the tree rows
– Forage oats at 50 lbs per acre
– Forage rape at 10 lbs per acre
– 50 lbs N fertilizer per acre
Preparation of Test PlotsPreparation of Test Plots
Electric fence and water supplies installed in late July, 2004
Introduction of SheepIntroduction of Sheep
Sheep were 4 to 4½ month old lambs, and weighed 60 to 65 pounds
Introduction of SheepIntroduction of Sheep
The number of sheep per plot ranged from 7 to 20 head, based on quality and quantity of forage
Introduction of SheepIntroduction of Sheep
Mid-month adjustment in number of head per plot, based on how rapidly the forage was being consumed and trampled
Results from Sheep Grazing Results from Sheep Grazing
Lambs gained 6 to 7 pounds during 29 days grazing on the test plots
Slightly below average weight gain compared to lambs grazing pasture with no supplemental feed
Failure of rape reduced the quality of forage; additional weight gains may have been seen had it established
Evaluation of the lambs during and at the end of the grazing period showed them to be vigorous and healthy
Results in Age 4 TreesResults in Age 4 Trees
Tree Tree AgeAge
(years)(years)
TreatmentTreatment 2004 2004 DiameterDiameterIncrementIncrement(inches)(inches)
2004 2004 HeightHeight
IncrementIncrement(feet)(feet)
DamageDamage
4 Grazed 1.2 11.2 Minor leaf browsing
4 Control 1.1 11.0 Nodamage
Results in Age 2 TreesResults in Age 2 Trees
Tree Tree AgeAge
(years)(years)
TreatmentTreatment 2004 2004 DiameterDiameterIncrementIncrement(inches)(inches)
2004 2004 HeightHeight
IncrementIncrement(feet)(feet)
DamageDamage
2 Grazed 0.8 7.7 Minor leaf browsing
2 Control 0.7 7.5 Nodamage
Results in Age 1 TreesResults in Age 1 Trees
Tree Tree AgeAge
(years)(years)
TreatmentTreatment 2004 2004 HeightHeight
IncrementIncrement(feet)(feet)
DamageDamage
1 Grazed 0.6 17% showed stem and/or terminal
damage
1 Control 0.6 Nodamage
Conclusions Conclusions
Minor positive growth impacts with no damage were seen in the 2 and 4 year old grazing plots
Trees age 2 and older can can be grazed successfully Trees that are 1 year old, even if established from
whips, suffer unacceptable levels of browse damage Sheep remained healthy and vigorous, but weight
gains were not exceptional
ObservationsObservations
Careful management of livestock density is critical Current grazing lease rates in the lower Columbia
River area do not justify the expense of sowing a cover crop for forage
Grazing only native vegetation could prove more cost effective and might substitute for one or more mechanical cultivations
As a result of this trial, approximately 500 sheep were wintered in several fields of the CTF, with favorable results reported by two different ranchers
AcknowledgementsAcknowledgements
This study was funded by a grant from Western Sustainable Agriculture Research and Education (WSARE), under project number FW04-109
We wish to acknowledge the contributions of:– McClellan “Mac” Stewart, Magruder Farms,
Clatskanie, Oregon, for technical assistance in selecting cover crops and managing livestock
– GMO Forestry Fund 3, Boston, Massachusetts, for their in-kind contribution of the land and tree plantations on which the study was conducted