SMC research program
Needed are reliable estimates of response to silvicultural treatments and management regimes, understanding of how product quality and value are influenced by these treatments and regimes, and methods for designing regimes that will produce high yields of wood with desirable properties.
Type VI Installations: late stage fertilization
This project will provide data for Cooperative members to determine the economic returns to late-rotation fertilization investments. These data will include the average, area-based volume response to late-rotation fertilization (i.e. within 8-10 of harvest) based on paired, fixed-area plots. Candidate plots will be drawn from managed stands in Oregon, Washington, and British Columbia that landowners already consider as candidates for fertilization; species composition will be at least 75% Douglas-fir by basal area, and at least 85% of the basal area being conifer. Typically, eligible stands between approximately 30 and 50 years total age from planting or ~25 to 45+ years breast height age. The result will be the Regional Response Estimate (RRE).
Type V Installations: Paired-tree fertilization trials
Paired-tree study consisting of two treatments, 0 and 224 Kg N/ha to study effects on growth, carbon, and wood quality. Stratified by parent material, vegetation zone, and slope location. Each installation has 12-20 tree pairs, soil moisture and temperature sensors, and precipitation gauges. 73 installations installed, measured and fertilized. Two and four-year response has been measured for all of the installations except for any installations that were damaged. Six-year response has been assessed on 27 of the installations.
Type IV Installations: Douglas-fir and western hemlock genetic gain trials
“Genetic Gain/Type IV” Planted in 2005 and 2006. A Douglas-fir genetic gain and spacing trial collaboration with Northwest Tree Improvement Cooperative. Planting spacings are 7x7, 10x10, and 15x15. Genetic levels are elite, unimproved and intermediate stock. Vegetation control levels are current practice and complete until crown closure. Temperature and precipitation gages and lysimeters at each installation. 6 installations, 132 plots in the Grays Harbor breeding zone.
Type III Installations: Douglas-fir and western hemlock spacing trials
Planted between 1985 and 2001 with the best current regeneration practices at 100, 200, 300, 440, 680, and 1210 stems per acre. Plantings were at least 3 acres per spacing to provide experimental material for future research. A control measurement sample plot was established in each spacing. In the three widest spacings additional plots were established to create a matrix of density and pruning (pruned with unpruned “followers” with pruning to either 50% live crown removal or pruned to 2.5 inch top) treatments. In the three dense spacings a matrix of thinning treatments; early/light, early/heavy, late/light, late/heavy, and a late one time, was established based on relative spacing. 47 installations; of which 38 are Douglas-fir, 6 are western hemlock, and 3 with a 50/50 mix of Douglas-fir and western hemlock. Collectively they have 564 plots.
Type II Installations: Douglas-fir and western hemlock thinning response
Established between 1986 and 1991 in Douglas-fir plantations that were approaching commercial thinning stage and considered to approximate the expected future condition of the Type I installations. Five plots, one unthinned control and four following thinning regimes based on Curtis’ relative density constitute the treatments. Originally 12 installations, 60 plots; currently 4 installations, 20 plots.
Type I Installations: Douglas-fir and western hemlock thinning response
Established between 1986 and 1994 in juvenile (age 7-15) Douglas-fir and western hemlock plantations with uniform stocking ranging from 300-680 stems per acre. Established before the onset of substantial inter-tree competition. At establishment, some plots were systematically thinned to 50% or 25% of the existing trees per acre. Seven plots constitute a common core on all installations and are following pre-defined thinning regimes based on Curtis’ relative density. At some installations counterparts to some of the core plots received best tree rather systematic spacing and others have either pruning or fertilization treatment. 38 installations, of which 30 are Douglas-fir, 322 plots, and 8 are western hemlock, 56 plots.
RFNRP: Regional Forest Nutrition Research Project
Phase 1: Unthinned natural stands of Douglas-fir and western hemlock. Installations were established in 1969-70, received as many as 4 fertilization treatments, and were measured for 20 years. Completed in 1990. 117 installations, 702 plots.
Phase 2: Thinned natural stands of Douglas-fir and western hemlock. Installations were established in 1971-72, received as many as 4 fertilization treatments, and were measured for 20 years. Completed in 1992. 43 installations, 266 plots.
Phase 3: Young thinned plantations of Douglas-fir and western hemlock, and low site quality stands of Douglas-fir. Installations were established in 1975, received as many as 4 fertilization treatments, and were measured for 20 years. Completed in 1996. 29 installations, 234 plots.
Phase 4: Pre-commercially thinned (300 trees/acre) plantations of Douglas-fir and western hemlock, and Douglas-fir stands of naturally low stocking. Installations were established in 1980, received as many as 4 fertilization treatments, and were measured for 20 years Completed in 2000. 34 installations, 306 plots.
Phase 5: Single-tree screening trials in young noble fir and Pacific silver fir stands; established 1986-1988. One fertilizer application. Completed in 1991. 73 installations.
SMC database(Restricted Access)
Plantation yield calculator
The Plantation Yield Calculator (PYC) is a succinct summarization of what SMC Silviculture Project Type I, II, and III installations are yielding over age across the region. Its function is to predict probable yields over a limited period of age extrapolation using the well-known Chapman-Richards flexible growth/yield curve. The yield models are implemented using a "runs-in-browser" tool, allowing the user to point and click choices for planting density, site index, elevation, location (latitude/longitude), and species (DF, WH, 50-50 mixtures). Currently, the SMC-PYC graphs yield over age, allowing simultaneous (side-by-side) comparison of a limited number of planting densities, as well as species comparisons, and also displays results in tabular format near the bottom of the browser window.
SMC Tree List Generator(Restricted Access)
The SMC tree list generator is comprised of a set of executable programs and a database of stand measurement data that are used to create simulated stands or tree lists from a per-unit-area description of a forest stand.
