Pacific Northwest Research Station

PNW > Research > Large Scale Siviculture Experiments > Density Management Study, Riparian Buffer

Large-Scale Silvicultural Experiments In Western Oregon and Washington

Density Management Study, Riparian Buffer

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.

Website: http://ocid.nacse.org/nbii/density/

(last accessed 2006-12-06)

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USDA Forest Service - Pacific Northwest Research Station
Last Modified:  Tuesday, 29 January 2008 at 17:11:07 EST