1. SilvoPasture with Hybrid Poplar and Sheep
GreenWood Resources
Columbia Tree Farm
Clatskanie, Oregon

2. GreenWood Resources, Inc.
Natural resource management company established in 1996, based in Portland, Oregon

3. GreenWood Resources, Inc.
Currently manage nearly 15,000 acres of hybrid poplar plantations
6,000 acres west of the Cascade Mountains
8,700 acres east of the Cascade Mountains

4. GreenWood Resources, Inc.
World-wide development and management of poplar plantations
Development of elite hybrid poplar and cottonwood genotypes
France
N. America
China
Japan
New Zealand
Chile

5. 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)

6. Creating Hybrid Poplars
Traditional hybridization through controlled pollination, propagation and testing of progeny

7. Uses of Hybrid Poplar Wood products including veneer & lumber
Photo courtesy of British Columbia Ministry of Forestry and Lands

8. Uses of Hybrid Poplar
Pulping fibers for the paper industry

9. Uses of Hybrid Poplar
Feedstock for energy industry; co-firing with coal and liquid fuels

10. Uses of Hybrid Poplar Land application of municipal effluent
Phytoremediation of industrial sites and waste water treatment

11. Uses of Hybrid Poplar
Carbon sequestration

12. The Columbia Tree Farm (CTF)
Established in 1982

13. The Columbia Tree Farm (CTF)
50% owned land, 50% leased

14. The Columbia Tree Farm (CTF)
Initially created to support area pulp and paper mills

15. The Columbia Tree Farm (CTF)
Operate as agriculture, employing many conventional farm practices and equipment

16. Characteristics 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

17. CTF 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

18. Challenges 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

19. Purpose 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 effective means of weed control in wider spaced plantations

20. Test Sites
4 year old trees, from 14” cuttings

21. Test Sites
2 year old trees, from ’ to 6’ tall whips

22. Test Sites
1 year old trees, from large 6’ to 7’ tall whips

23. Test Sites
Thirty-six-tree plots were established inside and outside of each grazing plot for evaluation and comparison of tree growth and performance

24. Preparation 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

25. Preparation of Test Plots
Oats established well, rape did not establish

26. Preparation of Test Plots
Electric fence and water supplies installed in late July, 2004

27. Introduction of Sheep Sheep placed on August 2nd, 2004
Sheep were 4 to 4½ month old lambs, and weighed 60 to 65 pounds
The number of sheep per plot ranged from 7 to 20 head, based on quality and quantity of forage
Targeted one month of grazing within each plot
Mid-month adjustment made in number of head per plot, based on how rapidly the forage was being consumed and/or trampled

28. Introduction of Sheep
Sheep were placed on August 2nd, 2004

29. Introduction of Sheep
Sheep were 4 to 4½ month old lambs, and weighed 60 to 65 pounds

30. Introduction of Sheep
The number of sheep per plot ranged from 7 to 20 head, based on quality and quantity of forage

31. Introduction of Sheep
Targeted one month of grazing within each plot

32. Introduction of Sheep
Mid-month adjustment in number of head per plot, based on how rapidly the forage was being consumed and trampled

33. 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

34. Results in Age 4 Trees Tree Age (years) Treatment
2004 Diameter Increment (inches)
2004 Height Increment (feet)
Damage 4
Grazed
1.2
11.2
Minor leaf browsing
Control
1.1
11.0
No damage

35. Results in Age 4 Trees

36. Results in Age 2 Trees Tree Age (years) Treatment
2004 Diameter Increment (inches)
2004 Height Increment (feet)
Damage 2
Grazed
0.8
7.7
Minor leaf browsing
Control
0.7
7.5
No damage

37. Results in Age 1 Trees Tree Age (years) Treatment
2004 Height Increment (feet)
Damage 1
Grazed
0.6
17% showed stem and/or terminal damage
Control
No damage

38. 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

39. Observations 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

40. Acknowledgements
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