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

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

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

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

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 Poplars Traditional hybridization through controlled pollination, propagation and testing of progeny

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

Uses of Hybrid Poplar Pulping fibers for the paper industry

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

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

Uses of Hybrid Poplar Carbon sequestration

The Columbia Tree Farm (CTF) Established in 1982

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

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

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

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

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

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

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

Test Sites 4 year old trees, from 14” cuttings

Test Sites 2 year old trees, from 5’ to 6’ tall whips

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

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

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

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

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

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

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

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

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

Introduction of Sheep Targeted one month of grazing within each plot

Introduction 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 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 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

Results in Age 4 Trees

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

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

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

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

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