Large-Scale Silvicultural Experiments In Western Oregon and Washington

Capitol Forest Study

Status: Complete     Dates: December 2004 

Project Contact: Curtis, Robert

Project Description

Initial Installation Years: 1998-2004

Primary Objectives: Create on-the-ground examples of a number of contrasting silvicultural systems (i.e., a range of disturbances and levels of retention) that can be evaluated for effectiveness in reducing visual and other environmental impacts of forestry operations, while providing high timber outputs over time. Monitor development of stands under these contrasting systems over an extended time period with procedures that will provide quantitative estimates of vegetation change and timber outputs, and statistically sound tests of differences between systems.

Pre-treatment Conditions: 40- to 70-year-old, even-aged Douglas-fir stands.

Locations: Blue Ridge (46.8500°N, 123.1500°W), Copper Ridge (47.0333°N, 123.0667°W), and Rusty Ridge (46.9500°N, 123.2000°W).

Initial Treatments: 5 thinning treatments and 1 unthinned control each replicated 1 time at 3 locations.

Map of Capitol Forest Study

No Overstory Removal (Control)

Control (1a). Provide a comparison with gains obtainable by the repeated thinning regime when some stands are held on an extended rotation as a means of adjusting currently unbalanced age distributions and reducing visual impacts on the landscape. Not thinned. Not planted. No woody debris or other initial treatments.

Light Overstory Removal

Repeated Thinning (2a). Extended rotation with repeated, light, commercial thinnings. Thinned 100% of stand to RD 40–50. Not planted. No woody debris or other initial treatments.

Moderate Overstory Removal

Group Selection (3a). Group selection uneven-age management, producing a unit consisting of five age classes on an approximately 50- to 75-year rotation. Thinned 80% of stand to RD 45 as needed. Cut 20% of stand in groups ranging from individual trees to groups of trees not larger than 1.5 acres in size on a 10- to 15-year cycle. Harvest groups dispersed throughout stand. Planted openings larger than 0.10 acre to Douglas-fir. Control competing vegetation as needed. No woody debris or other initial treatments.

Patch Cut (3b). Patch-wise uneven-age management, producing a unit consisting of five age classes on an approximately 50- to 75-year rotation. Thinned 80% of stand to RD 45 as needed. Cut 20% of stand to create somewhat irregularly shaped 1.5-acre to 5.0-acre patches on a 10- to 15-year cycle. Harvest patches dispersed throughout stand. Patches planted to Douglas-fir and/or a mix of Douglas-fir and other species. Control competing vegetation as needed. No woody debris or other initial treatments.

Heavy Overstory Removal

Two-Age (4a). Reserve shelterwood resembling a conventional shelterwood but with the overwood, or a portion of it, carried through the second rotation to provide large diameter trees and high-quality material. Thinned 100% of stand to 15 tpa (leave trees selected for spacing, vigor, and stem quality). Underplanted Douglas-fir. Control competing vegetation as needed. No woody debris or other initial treatments.

Complete Overstory Removal (Clearcut)

Clearcut (5a). Provide a direct quantitative comparison of clearcut costs and outputs with those of the other regimes. Clearcut 100% of stand, except for scattered groups of leave trees as needed to meet Washington Department of Natural Resources (WADNR) rules. Plant according to current WADNR practices. Control competing vegetation as needed. No woody debris or other initial treatments.

Response Variables: Over-, mid-, and understory vegetation; lichens, mosses, and bryophytes; birds; snags; social perceptions; wood production; economics; operational factors; forest floor.

Study Plan: Curtis, R.O.; Clendenen, G.W.; DeBell, D.S.; DeBell, J.; Shumway, J.; Poch, T. 2001 (revised; originally 1997). Silvicultural options for harvesting young-growth production forests. Part I. The stand-level silvicultural experiment. Study plan (silviculture). On file with: R. Curtis, U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Olympia Forestry Sciences Laboratory, 3625 93rd Avenue SW, Olympia, WA 98512. 

Clearwater Study

Status: Complete     Dates: December 1995 

Project Contacts: Crisafulli, Charlie; Harrington, Connie

Project Description

Initial Installation Years: 1994-1995

Primary Objectives: Evaluate short- and long-term growth and yield of overstory trees, stand differentiation, and variation in horizontal and vertical structure in response to alternative silvicultural prescriptions. Monitor short- and long-term population responses of small mammals, birds, amphibians, and vascular plants to the implementation of alternative silvicultural prescriptions. Accelerate the development of characteristics associated with late-successional forests.

Pre-treatment Conditions: 10- to 13-year-old, even-aged Douglas-fir plantations.

Locations: Clearwater Study (CWS; 46.2560°N, 121.9980°W) and Very Young Stand Management Study (VYSMS; 44.2528°N, 122.2064°W).

Initial Treatments: 4 thinning x planting treatments and 1 unthinned control each replicated 5 times at the CWS location and each 1 time at the VYSMS location.

No Overstory Removal (Control)

Treatment A: untreated control (1a). Provide a comparison between rates of stand development and differentiation with and without post-planting treatments. Not thinned. Not planted. No woody debris or other initial treatments.

Light Overstory Removal

None.

Moderate Overstory Removal

Treatment B: thinned (no gaps), not planted (3a). Emphasize uniformity of species composition and stand structure with a long-term goal of high-value wood production. Thinned 100% of stand uniformly to 340 tpa by removing alternate diagonal rows. Not planted. No woody debris or other initial treatments.

Heavy Overstory Removal

Treatment C: thinned (1 gap size), planted (4a). Increase tree species diversity without making major changes in uniformity of tree spacing. Thinned 100% of stand uniformly to 340 tpa by removing alternate diagonal rows. Removed additional 100 tpa to create eight uniformly distributed 42 ft x 42 ft (0.04 acre) gaps per acre. Planted with 100 tpa red alder in gap centers. Planted 40 tpa western hemlock and 40 tpa western redcedar on the gap edges. Planting was not as uniform as the treatment descriptions imply. No woody debris or other initial treatments.

Treatment D: thinned (3 gap sizes), not planted (4b). Increase structural heterogeneity. Treatment is designed to increase horizontal and vertical diversity (spatial heterogeneity) in the stand. Thinned 100% of stand uniformly to 340 tpa by removing alternate diagonal rows. Removed additional 100 tpa to create three different sized gaps: 16 ft x 28 ft, 28 ft x 42 ft, and 42 ft x 42 ft. Not planted. No woody debris or other initial treatments.

Treatment E: thinned (3 gap sizes), planted (4c). Increase species, vertical and horizontal diversity. Treatment is an attempt to accelerate the development of conditions associated with old-growth forests through intensive silviculture. Thinned 100% of stand uniformly to 340 tpa by removing alternate diagonal rows. Removed additional 100 trees/ac to create three different sized gaps: 16' x 28', 28' x 42', and 42' x 42'. Selected 30 large and vigorous trees/ac for growth enhancement. Kept 20 tpa of the growth enhancement trees in an open-grown situation to maximize growth. Planted 50 tpa red alder (7 ft x 7 ft spacing) in 28 ft x 41 ft and 41 ft x 41 ft gaps. Planted 75 tpa western hemlock and 75 tpa western redcedar (6 ft x 6 ft) in all three sized gaps. Planting was not as uniform as the treatment descriptions imply. No woody debris or other initial treatments.

Complete Overstory Removal (Clearcut)

None.

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

Study Plan: Crisafulli, C.M.; Harrington, C.A. 1994. Alternative silviculture in young Douglas-fir plantations: effects of stand composition and structure on plant and animal populations and on the production of forest products. Study plan. On file with: C. Harrington, U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Olympia Forestry Sciences Laboratory, 3625 93rd Avenue SW, Olympia, WA 98512.

Demonstration of Ecosystem Management Options Study

Status: Complete      Dates: December 1995 

Project Contacts: Poage, Nathan; Anderson, Paul

Project Description

Initial Installation Years: 1994-1995

Primary Objectives: Determine how the level of retention following overstory removal influences biological values and social perceptions of mature, coniferous forests. Determine whether, for a particular level of retention, spatial pattern of retention is important. Determine whether a 15% level of retention is sufficient to maintain the organisms and processes that characterize late-seral forests in the Pacific Northwest. Determine which species or groups of organisms are most sensitive to variation in the amount or spatial pattern of retention.

Pre-treatment Conditions: 65- to 170-year-old stands.

Locations: Butte (46.3720°N, 121.5920°W), Capitol Forest (46.8880°N, 123.1230°W), Dog Prairie (43.1960°N, 122.3060°W), Little White Salmon (45.8580°N, 121.7020°W), Paradise Hills (46.0030°N, 122.0430°W), and Watson Falls (43.2620°N, 122.2460°W).

Initial Treatments: 5 overstory removal treatments and 1 unthinned control each replicated 1 time at 6 locations.

No Overstory Removal (Control)

100% Retention (1a). Provide untreated control. Not thinned. Not planted. No woody debris or other initial treatments.

Light Overstory Removal

75% Aggregated Retention (2a). High retention in aggregated fashion. 3 circular 2.471-ac (1-ha) patches harvested in an evenly spaced triangular array removing 25% of the stand basal area. 2.6 snags/ac created in harvested areas from dominant/co-dominant trees. Planted ~165 to 300 tpa to achieve minimum stocking; mix comprised of 2-5 species which varied by geographic location. No additional woody debris or other initial treatments.

Moderate Overstory Removal

40% Aggregated Retention (3a). Moderate retention in aggregated fashion. 5 undisturbed 2.471-ac (1-ha) circular patches are retained evenly spaced within the harvest unit. Planting and snag treatments identical to DEMO treatment 2a. No additional woody debris or other initial treatments.

40% Dispersed Retention (3b). Moderate retention in dispersed fashion. Dominant and co-dominant trees are retained in an even distribution throughout the treatment unit; total basal area equivalent to that retained in DEMO treatment 3a. Planting and snag treatments identical to DEMO treatment 2a. No additional woody debris or other initial treatments.

Heavy Overstory Removal

15% Aggregated Retention (4a). Low retention (NWFP minimum) in aggregated fashion. 2 undisturbed 2.471-ac (1-ha) circular patches are retained at diagonally opposite positions within the harvest unit. Planting and snag treatments identical to DEMO treatment 2a. No additional woody debris or other initial treatments.

15% Dispersed Retention (4b). Low retention (NWFP minimum) in dispersed fashion. Dominant and co-dominant trees are retained in an even distribution throughout the treatment unit; total basal area equivalent to that retained in DEMO treatment 4a. Planting and snag treatments identical to DEMO treatment 2a. No additional woody debris or other initial treatments.

Complete Overstory Removal (Clearcut)

None.

Response Variables: Over-, mid-, and understory vegetation; bryophytes; arboreal mammals; small mammals; bats; birds; arthropods; amphibians; woody debris; fungi; microclimate; social perceptions; forest floor.

Study Plan: U.S. Department of Agriculture, Forest Service. 1996. Demonstration of Ecosystem Management Options: a study of green-tree retention levels and patterns in western Oregon and Washington. Unpublished study plan. On file with: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Portland Forestry Sciences Laboratory, 620 SW Main Street, Suite 400, Portland, OR 97205.

Density Management Study, Initial Thinning

Status: Complete     Dates: December 2000 

Project Contact: Anderson, Paul

Project Description

Initial Installation Years: 1996-2000

Primary Objectives: Evaluate effects of alternative forest density management treatments on important stand and habitat attributes in previously unthinned stands. Determine treatment effects on selected plant and animal taxa. Use these sites to develop operational approaches to implementation of new prescriptions, improve methods for effectiveness monitoring of plant and animal taxa, and to share results of on-the- ground practices and findings with land managers, regulatory agencies, policymakers, and the public.

Pre-treatment Conditions: 50- to 70-year-old stands.

Locations: Bottom Line (43.7722°N, 123.2364°W), Delph Creek (45.2656°N, 122.1592°W), Green Peak (44.3667°N, 123.4583°W), Keel Mountain (44.5281°N, 122.6319°W), North Soup (43.5658°N, 123.7772°W), OM Hubbard (43.2916°N, 123.5833°W), and Ten High (44.2806°N, 123.5183°W).

Initial Treatments: 3 thinning treatments and 1 unthinned control each replicated 1 time at 7 locations.

No Overstory Removal (Control)

Unthinned Control (1a). Not thinned. Underplanted nine 1-acre areas with western hemlock and western redcedar. No woody debris or other initial treatments.

Light Overstory Removal

High Density Retention (2a). Thinned 70-75% of stand to 120 tpa. Left 20-30% of stand as riparian buffers and/or leave islands of three sizes (0.25, 0.5, and 1.0 acres). Underplanted nine 1-acre areas with western hemlock and western redcedar. No woody debris or other initial treatments.

Moderate Overstory Removal

Moderate Density Retention (3a).Thinned 60-65% of stand to 80 tpa. Cut 10% of stand to create circular gaps (0.25, 0.5, and 1.0 acres). Left 10% of stand in circular leave islands (0.25, 0.5, and 1.0 acres). Left 15-20% of stand as unthinned riparian buffers. Underplanted nine 1-acre areas with western hemlock and western redcedar. Planted gaps with western hemlock, Douglas-fir, western redcedar, and grand fir. No woody debris or other initial treatments.

Variable Density Retention (3b). Thinned 10% of stand to 40 tpa, thinned 25-30% of stand to 80 tpa. Thinned 25-30% of stand to 120 tpa. Cut 10% of stand to create circular gaps (0.25, 0.5, and 1.0 acres). Left 10% of stand in circular leave islands (0.25, 0.5, and 1.0 acres). Left 15-20% of stand as unthinned riparian buffers. Planted gaps and underplanted 40 tpa overstory areas with western hemlock, Douglas-fir, western redcedar, and grand fir. No woody debris or other initial treatments.

Heavy Overstory Removal

None.

Complete Overstory Removal (Clearcut)

None.

Response Variables: Over-, mid-, and understory vegetation; lichens, mosses, and bryophytes; birds; arthropods; amphibians; mollusks; snags; woody debris; fungi; microclimate; forest floor.

Study Plan: Cissel, J.H.; Anderson, P.D.; Berryman, S.; Chan, S.S.; Olson, D.H.; Puettmann, K.J.; Thompson, C. 2006. BLM Density Management and Riparian Buffer Study: establishment report and study plan. Scientific Investigations Report 2006–5087. Reston, VA: U.S. Department of the Interior, Geological Survey. 144 p.

Density Management Study, Re-Thinning

Status: Complete    Dates: December 2007 

Project Contact: Anderson, Paul

Project Description

Initial Installation Years: 1996-2007

Primary Objectives: Evaluate effects of alternative forest density management treatments on important stand and habitat attributes in stands thinned 25-30 years earlier to >100 tpa. Determine treatment effects on selected plant and animal taxa. Use these sites to develop operational approaches to implementation of new prescriptions, improve methods for effectiveness monitoring of plant and animal taxa, and to share results of on-the-ground practices and findings with land managers, regulatory agencies, policymakers, and the public.

Pre-treatment Conditions: 60- to 90-year-old stands.

Locations: Blue Retro (43.2803°N, 124.0825°W), Little Wolf (43.4222°N, 123.6292°W), North Ward (43.7689°N, 123.2014°W), Perkins Creek (43.7142°N, 122.9131°W), and Sand Creek (44.8347°N, 123.5906°W).

Initial Treatments: 1 thinning treatment and 1 unthinned control each replicated 1 time at 5 locations.

No Overstory Removal (Control)

Unthinned Control (1a). 25–30 years prior to initial DMS_RT treatments, overstory density reduced to >100 tpa in a single commercial thinning. Initial DMS_RT thinning: not thinned. Not planted. No woody debris or other initial treatments.

Light Overstory Removal

None.

Moderate Overstory Removal

Re-Thin (3a). 25–30 years prior to initial DMS_RT treatments, overstory density reduced to >100 tpa in a single commercial thinning. Initial DMS_RT thinning: thinned 100% of stand to a clumpy distribution of 40–60 tpa. Not planted. No woody debris or other initial treatments.

Variable Density Retention (3b). Thinned 10% of stand to 40 tpa, thinned 25-30% of stand to 80 tpa. Thinned 25-30% of stand to 120 tpa. Cut 10% of stand to create circular gaps (0.25, 0.5, and 1.0 acres). Left 10% of stand in circular leave islands (0.25, 0.5, and 1.0 acres). Left 15-20% of stand as unthinned riparian buffers. Planted gaps and underplanted 40 tpa overstory areas with western hemlock, Douglas-fir, western redcedar, and grand fir. No woody debris or other initial treatments.

Heavy Overstory Removal

None.

Complete Overstory Removal (Clearcut)

None.

Response Variables: Over-, mid-, and understory vegetation; snags; woody debris; forest floor.

Study Plan: Cissel, J.H.; Anderson, P.D.; Berryman, S.; Chan, S.S.; Olson, D.H.; Puettmann, K.J.; Thompson, C. 2006. BLM Density Management and Riparian Buffer Study: establishment report and study plan. Scientific Investigations Report 2006–5087. Reston, VA: U.S. Department of the Interior, Geological Survey. 144 p.

Density Management Study, Riparian Buffer

Status: Complete  Dates: December 2001  

Project Contacts: Anderson, Paul

Project Description

Initial Installation Years: 1996-2001

Primary Objectives: Characterize stream habitats and aquatic-dependent vertebrate diversity patterns in headwater stream networks. Examine effects of headwater aquatic vertebrate assemblages and their habitats of different riparian buffer widths within early successional forests subject to upslope timber thinning experiments; examine these findings in light of study of streamside-to-upslope vegetation, microhabitat, and microclimate regimes. Evaluate microclimate, microsite, and light responses to upland density management treatments and different riparian buffers.

Pre-treatment Conditions: 50- to 90-year-old stands.

Locations: Bottom Line (43.7722°N, 123.2364°W), Callahan Creek (43.8347°N, 123.5906°W), Cougar (44.5117°N, 123.6636°W), Delph Creek (45.2656°N, 122.1592°W), Grant (44.5117°N, 123.7642°W), Green Peak (44.3667°N, 123.4583°W), Keel Mountain (44.5281°N, 122.6319°W), North Soup (43.5658°N, 123.7772°W), North Ward (43.7689°N, 123.2014°W), OM Hubbard (43.2916°N, 123.5833°W), Perkins Creek (43.7142°N, 122.9131°W), Schooner (44.9358°N, 123.8558°W), and Ten High (44.2806°N, 123.5183°W).

Initial Treatments: 4 buffer width treatments and 1 unthinned control each replicated 0-1 times at 13 locations.

No Overstory Removal (Control)

Unthinned Control (1a). Provide baseline characteristics. Provide maximum buffer capacity for bank stability, coarse wood recruitment, and microclimate moderation; no environmental challenge. Not thinned. Riparian areas not planted. No woody debris or other initial treatments.

Light Overstory Removal

Two Site-Potential Tree Heights Buffer (2a). Provide high buffer capacity for bank stability, coarse wood recruitment, and microclimate moderation; low environmental challenge. Overstory thinned or clearcut upslope of unthinned buffer width of ~480 ft, measured as slope distance from stream. Riparian areas not planted. No woody debris or other initial treatments.

Moderate Overstory Removal

One Site-Potential Tree Height Buffer (3a). Provide high buffer capacity for bank stability, coarse wood recruitment, and microclimate moderation; moderate environmental challenge. Overstory thinned or clearcut upslope of unthinned buffer width of ~240 ft, measured as slope distance from stream. Riparian areas not planted. No woody debris or other initial treatments.

Heavy Overstory Removal

Variable Break Buffer (4a). Provide moderate buffer capacity for bank stability, coarse wood recruitment, and microclimate moderation; high environmental challenge. Overstory thinned or clearcut upslope of unthinned buffer of variable width, determined by on-site streamside ecological breaks in vegetation and slope character. Minimum buffer width of 50 ft, measured as slope distance from stream. Riparian areas not planted. No woody debris or other initial treatments.

Streamside Retention Buffer (4b). Provide moderate buffer capacity for bank stability, coarse wood recruitment, and microclimate moderation; high environmental challenge. Overstory thinned or clearcut upslope of unthinned buffer of variable width, determined by trees that directly confer both streambank stability by their rooting position next to streams and overhead shading by their crowns extending over the channel. Buffer width generally defined by trees within 20 ft of the channel. Riparian areas not planted. No woody debris or other initial treatments.

Complete Overstory Removal (Clearcut)

None.

Response Variables: Over-, mid-, and understory vegetation; lichens, mosses, and bryophytes; arthropods; amphibians; fish; mollusks; snags; woody debris; fungi; microclimate; hydrology; forest floor.

Study Plan: Cissel, J.H.; Anderson, P.D.; Berryman, S.; Chan, S.S.; Olson, D.H.; Puettmann, K.J.; Thompson, C. 2006. BLM Density Management and Riparian Buffer Study: establishment report and study plan. Scientific Investigations Report 2006–5087. Reston, VA: U.S. Department of the Interior, Geological Survey. 144 p.

Forest Ecosystem Study

Status: Complete    Dates: December 1993 

Project Contacts: Anderson, Paul

Project Description

Initial Installation Years: 1991-1993

Primary Objectives: Determine if woody plant species diversity, spatial heterogeneity in vegetation, and vertical diversity in vegetation can be manipulated through variable-density thinning and underplanting that do not require replacing the existing stand. Determine if enhancing the growth and diversity of woody plants will be accompanied by increased abundance and diversity of ectomycorrhizal fungi. Determine if increasing den availability through direct intervention (creating cavities in live trees and adding nest boxes) will increase flying squirrel populations.

Pre-treatment Conditions: 55- to 65-year-old, even-aged Douglas-fir stands.

Locations: Fort Lewis (46.9900°N, 122.6900°W).

Initial Treatments: 2 thinning x den augmentation treatments and 2 unthinned control x den augmentation treatments each replicated 4 times at 1 location.

No Overstory Removal (Control)

Control, no den augmentation (1a). Not thinned. Not planted. No den augmentation. No woody debris or other initial treatments.

Control, den augmentation (1b). Identical to FES treatment 1a but with den augmentation (i.e., nest boxes installed and/or cavities created).

Light Overstory Removal

None.

Moderate Overstory Removal

Variable Density Thinning, no den augmentation (3a). Root-rot thinning applied to ~15% of stand: low vigor trees removed and apparently healthy trees retained, producing residual densities of ~16 tpa > 7.9 in dbh (RD 1.5, metric). Light thinning applied to 50–60% of stand: thinning of subordinate and codominant trees > 7.9 in dbh to reduce the density of overstory to RD 6 (metric) with a thinning ratio d/D of 0.8–1.0, or ~125 tpa with an average spacing of ~19 ft between trees. Heavy thinning applied to 25–30% of stand: thinning of subordinate and codominant trees > 7.9 in dbh to reduce the density of overstory to RD 4 (metric), or ~75 tpa with an average spacing of ~24 ft between trees. Marking guidelines specified retention of all large standing dead trees and all deciduous trees. Not planted. No den augmentation. No woody debris or other initial treatments.

Variable Density Thinning, den augmentation (3b). Identical to FES treatment 3a but with den augmentation (i.e., nest boxes installed and/or cavities created).

Heavy Overstory Removal

None.

Complete Overstory Removal (Clearcut)

None.

Response Variables: Over-, mid-, and understory vegetation; arboreal mammals; small mammals; birds; arthropods; amphibians; snags; woody debris; fungi; soils; microclimate; forest pathology; roads.

Study Plan: Carey, A.B.; Thysell, D.R.; Brodie, A.W. 1999. The Forest Ecosystem Study: background, rationale, baseline conditions, and silvicultural assessment. Gen. Tech. Rep. PNW-GTR-457. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 129 p.

Long-Term Ecosystem Productivity Study

Status: Complete    Dates: December 1998

Project Contact: Harrington, Connie

Project Description

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

None.

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

None.

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.

Website (last accessed 2006-12-06)

Olympic Habitat Development Study

Status: Complete    Dates: December 2006 

Project Contact: Harrington, Connie

Project Description

Initial Installation Years: 1997-2006

Primary Objectives: Test management alternatives for their ability to accelerate development of characteristics associated with older stands. Test if accelerated development of the structures that are missing in the younger stands will increase the function of the ecosystem as habitat for forest-floor dwelling terrestrial amphibians and small mammals.

Pre-treatment Conditions: 35- to 62-year-old, even-aged stands.

Locations: Bait (47.3900°N, 123.9100°W), Clavicle (48.0400°N, 124.2100°W), Eats (47.5700°N, 124.0400°W), Fresca (48.0500°N, 124.2900°W), North Fork Fulton (47.6500°N, 123.0000°W), Rail (48.0600°N, 124.0700°W), Snow White (47.9300°N, 122.9700°W), and Triton (47.6200°N, 123.0100°W).

Initial Treatments: 4 thinning x planting x woody debris treatments and 1 unthinned control each replicated 1 time at 8 locations.

No Overstory Removal (Control)

Control (1a). Not thinned. Not planted. No woody debris or other initial treatments.

Light Overstory Removal

None.

Moderate Overstory Removal

Variable Density Thinning, not planted, CWD clumped, slash dispersed (3a). Thinned 75% of stand to 75% of pretreatment basal area. Cut 15% of stand to create small gaps. Left 10% of stand as uncut patches ("skips"). Not planted. CWD clumped and slash dispersed. No other initial treatments.

Variable Density Thinning, not planted, CWD dispersed, slash dispersed (3b). Identical to OHDS treatment 3a, but with CWD dispersed and slash dispersed.

Variable Density Thinning, planted, CWD clumped, slash clumped (3c). Identical to OHDS treatment 3a, but native understory species planted or seeded in existing or newly created openings and with CWD clumped and slash clumped.

Variable Density Thinning, not planted, CWD removed, slash dispersed (3d). Identical to OHDS treatment 3a, but with CWD removed and slash dispersed.

Heavy Overstory Removal

None.

Complete Overstory Removal (Clearcut)

None.

Response Variables: Over-, mid-, and understory vegetation; mosses; large, arboreal, and small mammals; bats; arthropods; amphibians; mollusks; snags; woody debris; fungi; microclimate; wood production; operational factors; roads; forest floor.

Study Plan: Harrington, C.A.; Carey, A.B. 1997. The Olympic Habitat Development Study conceptual study plan. On file with: C. Harrington, U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Olympia Forestry Sciences Laboratory, 3625 93rd Avenue SW, Olympia, WA 98512.

For more information, visit Olympic Habitat Development Study.

Siuslaw Thinning and Underplanting For Diversity Study

Status: Complete    Dates: December 1993 

Project Contact: Anderson, Paul

Project Description

Initial Installation Years: 1992-1993 Primary Objectives: Characterize the effects of thinning to increase structural heterogeneity and underplanting on stand composition, structure, vegetative diversity, and productivity in young, even-age Douglas-fir stands of high site index in the Oregon Coast Range.

Pre-treatment Conditions: 30- to 33-year-old, even-aged, Douglas-fir plantations.

Locations: Cataract (44.0700°N, 123.9500°W), Wildcat (45.2000°N, 123.7800°W), and Yachats (44.2800°N, 123.9400°W).

Initial Treatments: 3 thinning treatments and 1 unthinned control each replicated 1 time at 3 locations. All thinned treatments and unthinned control were underplanted with a 1:1 mix of Douglas-fir and western hemlock at 10 ft x 10 ft spacing with root rot pockets planted to red alder. Imbedded within each overstory treatment were three underplanting trials. First, two 1-ac areas within each treatment unit were either underplanted with Douglas-fir and western hemlock at 15 ft x 15 ft (species alternating within rows), or left unplanted. In a second conifer species trial, a single subplot per unit was planted with Douglas-fir, grand fir, western redcedar, western hemlock, Sitka spruce, and Pacific yew. Each conifer species was planted at 4.9 ft x 4.9 ft spacing in 13 four-seedling clusters arranged as a 6 x 13 grid of randomly selected clusters, for a total of 52 seedlings of each species. A third planting trial consisted of red alder and bigleaf maple planted in alternate species rows of 16 seedlings at 7.9 ft x 7.9 ft spacing. A total of 48 hardwood seedlings / species / treatment were planted on each site. Conifer planting occurred the winter after the block was thinned; hardwood planting occurred in the winter of 1994 at all three sites.

No Overstory Removal (Control)

No Thin (1a). Passive management. Provide internal reference. Not thinned. Underplanted (see above). No woody debris or other initial treatments.

Light Overstory Removal

Narrow Thin (2a). Grow large overstory trees, create understory-midstory cohorts, recruit coarse wood. Three-step overstory reduction to minimum density, repeated release of underplanted trees and natural regeneration. Thinned 100% of stand to ~100 tpa. Underplanted (see above). Slash cut to facilitate 15 x 15 planting. No woody debris or other initial treatments.

Moderate Overstory Removal

Wide Thin (3a). Grow large overstory trees, create understory-midstory cohorts, recruit coarse wood. Two-step overstory reduction to minimum density, single release of underplanted trees and natural regeneration. Thinned 100% of stand to ~60 tpa. Underplanted (see above). Slash cut to facilitate 15 x 15 planting. No woody debris or other initial treatments.

Heavy Overstory Removal

Very Wide Thin (4a). Grow large overstory trees, create understory-midstory cohorts, recruit coarse wood. One-step overstory reduction to minimum density, single release of underplanted trees and natural regeneration. Thinned 100% of stand to ~30 tpa. Underplanted (see above). Slash cut to facilitate 15 x 15 planting. No woody debris or other initial treatments.

Complete Overstory Removal (Clearcut)

None.

Response Variables: Over-, mid-, and understory vegetation; mosses; snags; woody debris; microclimate; wood production; economics; operational factors; forest floor.

Study Plan: Tucker, G.F.; Emmingham, W.H.; Johnston, S.; Chan, S.S.; Minore, D.; Owston, P.; McCreight, R.W.; Hayes, J.P. 1993. Commercial thinning and underplanting to enhance structural diversity of young Douglas-fir stands in the Oregon Coast Range. Adaptive COPE 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.

Uneven-Aged Management Project

Status: Complete    Dates: December 2000 

Project Contact: Anderson, Paul

Project Description

Initial 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 (44.2192°N, 122.2042°W).

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.

Young Stand Thinning and Diversity Study

Status: Complete    Dates: December 1996 

Project Contact: Anderson, Paul

Project Description

Initial Installation Years: 1994-1996

Primary Objectives: Provide scientific information on the biological consequences of thinning. Provide agencies with experience in adaptive management which enhances both the creation of timber-related jobs and increased production and utilization of wood fiber.

Pre-treatment Conditions: 35- to 45-year-old, even-aged, Douglas-fir plantations.

Locations: Christy Flats (43.8857°N, 122.3438°W), Cougar Reservoir (44.1000°N, 122.2500°W), McKenzie Mill (44.1786°N, 122.2708°W), and Tumble Creek (43.8714°N, 122.3333°W).

Initial Treatments: Three thinning treatments and one unthinned control each replicated 1 time at 4 locations.

No Overstory Removal (Control)

Control (1a). No treatment. Provide baseline. Not thinned. Not planted. No woody debris or other initial treatments.

Light Overstory Removal

Light Thin, no gaps (2a). Timber production and wood quality. Thinned 100% of stand to 100–110 tpa. Not planted. No woody debris or other initial treatments.

Light Thin, gaps (2b). Maximum horizontal and vertical heterogeneity. Patch-level approach to creating and enhancing the understory. Thinned 80% of stand to 100–110 tpa. Cut 20% of stand to create 0.5-acre gaps one tree height in diameter (~80 ft at initial treatment). Gaps planted. No woody debris or other initial treatments.

Moderate Overstory Removal

None.

Heavy Overstory Removal

Heavy Thin (4a). Accelerate the development of late-successional habitat. Stand-level approach to creating and enhancing the understory. Thinned 100% of stand to 50–55 tpa. Underplanted. No woody debris or other initial treatments.

Complete Overstory Removal (Clearcut)

None.

Response Variables: Over-, mid-, and understory vegetation; small mammals; birds; snags; woody debris; fungi; soils; social perceptions; wood production, operational factors; forest floor.

Study Plan: No formal study plan found, although several study plan-like files exist. 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.

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