Author: Harold S. DixonPublisher:
ISBN:
Category : Forest regeneration
Languages : en
Pages : 54
Book Description
Natural Regeneration Study in Western Oregon
Author: Harold S. DixonPublisher:
ISBN:
Category : Forest regeneration
Languages : en
Pages : 54
Book Description
Density Management and Riparian Buffer Study in Western Oregon
Author: Publisher:
ISBN:
Category : Buffer zones (Ecosystem management)
Languages : en
Pages : 8
Book Description
Growth and Yield, Structure, Composition, and Soil Compaction in a Western Oregon Douglas-fir Forest After 35 Years of Modified Selection Thinning
Author: Darin S. StringerPublisher:
ISBN:
Category : Douglas fir
Languages : en
Pages : 220
Book Description
Modified selection thinning has been utilized by some non-industrial foresters in Douglas-fir forests of Western Oregon and Washington for at least 35 years. This silvicultural strategy has not been tested, but has often been associated with reduced volume production and other undesirable effects. It continues to be used on many small woodland properties. This case study evaluated a management system that has utilized modified selection thinning and natural regeneration since 1964, on a 250 acre private forest tract on the east slopes of the Oregon Coast Range. Six conditions (Types) were identified and mapped on the property based on the number of thinning entries and stand vegetation conditions. Current field data along with past cruise information and aerial photos were used to assess past and current volume production, stand structure, species composition arid soil compaction. Stand growth and yield was projected for 100 years using a simulation model to compare selection thinning and short rotation evenage management. At the Tract level, inventory records showed standing conifer volume from 1964-95 increased from 1,939 MBF (thousand board feet) to 2,150 MBF, while 5,606 MBF of volume was removed. Harvests occurred every 1-4 years with an average volume of 715 bd. ft./acre/year removed. Stands in early stages of conversion with modified selection thinning were growing at 80-100% of potential based on regional growth and yield tables for stands of similar site quality and stocking. Volume growth in stands in intermediate stages of conversion was 35-70% of potential compared to the same yield tables adjusted for stocking. Under a similar management regime, simulated total Tract standing volume increased to 4,250 MBF after a 100-year projection with harvests of 600 bd. ft./acre/year. Tract average periodic annual increment after 100 years was similar to current levels. Simulation studies showed that selection thinning yielded 9% less total Tract board foot volume (standing + harvest) than 50-year rotation evenage management after a 100- year simulation. Two of six stand Types simulated with selection thinning produced yields within 2% of the 50-year rotation evenage system after 100 years. The other four Types produced from 8-20% less volume. Under modified selection thinning the Tract contained 3 times more standing volume, and produced 2.8 times more volume in logs greater than 16 inches (scaling diameter) after 100 years. Management using modified selection thinning maintained a per acre average of at least 10 MBF/acre standing timber over 90% of simulation period vs. 40% for the evenage regime. Modified selection thinning between 1964-1995 led to changes in stand structure and composition. Both conifer reproduction and shrub cover increased in stands with more thinning. Conifer basal area decreased with thinning but the range of tree diameters increased. Composition of natural regeneration in the understory of stands thinned 9-12 times was dominated by Douglas-fir with 47% stocking and 290 trees per acre. Past and current cruise reports along with aerial photographs indicate hardwoods increased during the management period between 1964-97. Soil compaction was significantly higher in areas thinned 9-12 times vs. those thinned 1-4 times (p-value =.04), and was significantly higher in areas with less than 35% slope (p-value =.001). Across the Tract 60% of sampling points fell in a low compaction class, 33% in moderate, and 4% in high. Uneven-aged stand structure in a group selection sense was observed at the Tract level. Individual stands or plots did not contain functional individual tree selection uneven-aged structure. However, stands thinned repeatedly were two-storied in places. Based on comparison of different stand Types it appears modified selection thinning in Douglas-fir stands could be used to perpetuate even-aged structure, or to convert stands towards an uneven-aged condition. In either scenario, management is recommended to address increased hardwood stocking, inconsistent natural regeneration of conifer species, and understory growth losses caused by reserve "legacy" trees.
Results of Shelterwood Harvesting of Douglas-fir in the Cascades of Western Oregon
Author: Richard L. WilliamsonPublisher:
ISBN:
Category : Douglas fir
Languages : en
Pages : 20
Book Description
Timber Harvest Projections for Private Land in Western Oregon
Author: Darius Mainard AdamsPublisher:
ISBN:
Category : Forest productivity
Languages : en
Pages : 48
Book Description
In this analysis, volume-flow and market-based models of the western Oregon timber sector are developed. The volume-flow model finds the maximum, long-term, even-flow level of cut for each ownership (industry and non-industrial private forest). The market model simulates the interaction of log demand and timber owner supply to find the market balancing harvest quantity and log price. In both models, owner decisions on the intensity of timber management (silviculture) are made within the models consistent with owner objectives (volume or wealth maximization). Model projections suggest that western Oregon forest industry owners could sustain cut at recent (1995-1999) levels, stemming the 40-yr declining trend in their harvest. Nonindustrial private forest owners could raise harvests to near historical peak levels. These harvests could be maintained over the next five decades with no reduction in the growing stock inventory. Management would continue to shift toward the more intensive forms on both ownerships. The average age of the inventory would decline over the projection. Simulated riparian protection policies lower harvest roughly in proportion to the land base reduction and raise log prices. A policy to increase the minimum age of clearcut harvests would lead to large near-term reductions in industrial harvest but less marked reductions on NIPF lands. Prices would rise sharply in the near term. Over the longer term, the policy would act to expand inventory, raising harvest, and to depress prices.
Research Bulletin
Author: Oregon State Board of ForestryPublisher:
ISBN:
Category : Forests and forestry
Languages : en
Pages : 56
Book Description
Research Paper INT.
Author: Publisher:
ISBN:
Category : Forests and forestry
Languages : en
Pages : 346
Book Description
Research Paper PNW.
Author: Publisher:
ISBN:
Category : Forests and forestry
Languages : en
Pages : 636
Book Description
U.S. Forest Service Research Paper PNW.
Author: USDA Forest Service Research Paper PNW.
Author: Pacific Northwest Forest and Range Experiment Station (Portland, Or.)Publisher:
ISBN:
Category : Forests and forestry
Languages : en
Pages : 28
Book Description