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Pacific Northwest Research Station
Large-Scale Silvicultural Experiments In Western Oregon and Washington
Long-Term Ecosystem Productivity Study
Initial Installation Years: 1996-1998
Primary Objectives: Determine how potential and realized productivity are affected by the pathway along which succession is directed by management practices. Determine how altering the amount of periodic inputs of organic matter to the forest floor can influence long-term ecosystem productivity. Determine effects of underburning on the late-seral treatment.
Pre-treatment Conditions: 70- to 100-year-old, even-aged stands.
Locations: Hebo (45.2167°N, 123.7500°W), Isolation (44.0667°N, 122.4000°W), Sappho (48.0667°N, 124.2500°W), and Siskiyous (42.3333°N, 124.1667°W).
Initial Treatments: 1 thinning treatment, 2 clearcutting treatments, and 1 unthinned control each replicated 3-4 times at 4 locations.
No Overstory Removal (Control)
Control (1a). Not thinned. Not planted. No organic matter removal. No other initial treatments.
Light Overstory Removal
Moderate Overstory Removal
Late-Successional, organic matter retention (3a). Initial thinning to move stands into understory re-initiation phase. Thinned 100% of stand to ~80 tpa. Underplanted ~150 tpa shade-tolerant conifers (e.g., western hemlock, western redcedar, Pacific yew, sugar pine). Organic matter retained. No other initial treatments.
Late-Successional, organic matter removal (3b). Identical to LTEP treatment 3a, but with organic matter removed.
Heavy Overstory Removal
Complete Overstory Removal (Clearcut)
Early-Successional, organic matter retention (5a). Re-initiate stand development with a stand that emphasizes early seral species for up to 2/3 of the rotation. Clearcut 100% of stand. Planted ~150-200 tpa of Douglas-fir and ~50 tpa of hardwoods (e.g., red alder, bigleaf maple). Organic matter retained. No other initial treatments.
Early-Successional, organic matter removal (5b). Identical to LTEP treatment 5a, but with organic matter removed.
Mid-Successional, organic matter retention (5c). Re-initiate stand development with a stand that emphasizes Douglas-fir bole growth. Clearcut 100% of stand. Planted ~600-800 tpa of Douglas-fir. Organic matter retained. No other initial treatments.
Mid-Successional, organic matter removal (5d). Identical to LTEP treatment 5c, but with organic matter removed.
Response Variables: Over-, mid-, and understory vegetation; lichens; small mammals; birds; reptiles and amphibians; snags; woody debris; fungi; soils; climate; forest pathology; social perceptions; wood production; forest floor.
Study Plan: Little, S.; Bormann, B.; Bednar, L.; Wurtz, T.; Zasada, J.; McClellan, M.; Shainsky, L.; Boyle, J.; Castellano, M.; Amaranthus, M.; Harrington, C.; Zabowski, D.; Geist, M. 2000. Long-Term Ecosystem Productivity (LTEP) program governing research plan for the integrated research sites. On file with: B. Bormann, U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Corvallis Forestry Sciences Laboratory, 3200 SW Jefferson Way, Corvallis, OR 97331.
(last accessed 2006-12-06)
US Forest Service - Pacific Northwest Research Station