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PNW > Research > Large Scale Siviculture Experiments > Uneven-Aged Management Project


Large-Scale Silvicultural Experiments In Western Oregon and Washington

Uneven-Aged Management Project

Uneven-Aged Management Project MapInitial Installation Years: 1997-2000

Primary Objectives: Determine the ecological and economic trade-offs involved in converting young Douglas-fir plantations at mid-elevation in the central Oregon Cascades to a mixed-species and uneven-aged condition.

Pre-treatment Conditions: 35- to 47-year-old, even-aged, Douglas-fir plantations.

Locations: H.J. Andrews Experimental Forest (44.2192N, 122.2042W).

Initial Treatments: 3 thinning treatments and 1 unthinned control each replicated 4 times at 1 location.

No Overstory Removal (Control)

Control (1a). Passive management. Provide internal reference. Not thinned. Not planted. No woody debris or other initial treatments.

Light Overstory Removal

Single Tree Selection (2a). Repeated light commercial thinning to residual stocking levels creating understory light sufficient for establishment and recruitment of naturally regenerated shade tolerant tree species, along with planted shade-intolerant tree species. With repeated entries stands will ultimately consist of ~10 cohorts dominated by shade-intolerant species. Thinned 100% of stand from below to RD 30. Underplanted stand with an even mixture of Douglas-fir, western hemlock, western white pine, and western redcedar at a 10' x 10' spacing. No woody debris or other initial treatments.
Group Selection (2b). Repeated light commercial thinning combined with gap creation to favor recruitment by shade intolerant tree species. Final stand consisting of ~10 cohorts, dominated by Douglas-fir. Thinned 90% of stand from below to RD 30. Cut 10% of stand to create circular gaps one tree height in diameter (~80' at initial treatment). Planted gaps with an even mixture of Douglas-fir, western hemlock, western white pine, and western redcedar at an 8 x 8 spacing (only gaps were planted). No woody debris or other initial treatments.

Moderate Overstory Removal

None.

Heavy Overstory Removal

Multi-Storied Stand (4a). Repeated heavy commercial thinning to residual stocking levels creating understory light levels sufficient for establishment and recruitment of shade intolerant tree species - natural and planted. Stands will ultimately consist of ~5 cohorts with first 2-3 dominated by Douglas-fir and later cohorts dominated by more shade tolerant species. Thinned 100% of stand from below to RD 20. Underplanted stand with an even mixture of Douglas-fir, western hemlock, western white pine, and western redcedar at a 10' x 10' spacing. No woody debris or other initial treatments.

Complete Overstory Removal (Clearcut)

None.

Response Variables: Over-, mid-, and understory vegetation; lichens, mosses, and bryophytes; snags; woody debris; wood production; forest floor.

Study Plan: Tucker, G.F.; Emmingham, W.H.; Overton, J.P.; McKee, W.A.; Mayo, J.H.; Cissel, J.H. 2001. The H.J. Andrews Experimental Forest Uneven-Aged Management Project: study plan. On file with: P. Anderson, U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Corvallis Forestry Sciences Laboratory, 3200 SW Jefferson Way, Corvallis, OR 97331.

Website: http://www.fs.fed.us/pnw/bcfp/research_projects/UAMP.htm

(last accessed 2006-12-06)

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US Forest Service - Pacific Northwest Research Station
Last Modified: Monday,16September2013 at17:35:02CDT


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