Tree Species Characteristics SpeciesShade ToleranceTypical LongevityDurability Western HemlockVery Tolerant yearsIntermediate Western RedcedarVery Tolerant1000+ yearsVery Durable Grand FirTolerant yearsVulnerable Douglas FirIntermediate yearsDurable Big Leaf MapleIntermediate yearsDurable Red AlderIntolerant yearsIntermediate Black CottonwoodVery Intolerant yearsDurable
Evidence of root rot infestation. Root wads appear incomplete, or “fist-like“, due to root decay. Fallen trees are “jack-strawed” and do not appear directionally felled, as in windthrow.
Later evidence of bark beetle infestation. The first signs of attack are pitch tubes marking where female beetles have entered the tree. Secondary evidence is dry boring dust, similar to fine sawdust, found in bark crevices and around the tree base.
Crown type classifications of trees in even-age stands. D= dominant, C= codominant, I= intermediate, W= wolf, S= suppressed, M= mortality. The “crown ratio” is the proportion of total tree height that is occupied by live crown. In this illustration, the dominants have a 50 percent crown ratio; the wolf tree has an 80 percent crown ratio.
Silvicultural Systems Simplified Cultivation of forests through comprehensive programs of stand treatments, commonly classified by reproduction method. Even-Aged Reproduction Methods Clearcutting Seed-Tree Shelterwood Uneven-Aged Reproduction Methods Selection
A heavily thinned stand at age 50 – 30 years after the first thinning. This is a highly productive site where thinnings have reduced stand density to a low number of large trees. The open condition has allowed the development of understory plants. A portion of the same stand, un-thinned, at age 50. The stand has developed to a high density with many smaller trees and few plants growing in the understory because of a lack of light reaching the ground.
Logging Equipment Cable yarding systems Ground-based yarding systems
A small cable yarding system equipped with a motorized, clamping carriage is commonly employed to selectively harvest timber on steep slopes or over vulnerable soils. Use of intermediate supports can extend yarding distances, thereby reducing the costs and impacts of road construction.
Motorized carriage in action!
Left and right sides of the graph represent traction under the best conditions, but soil and weather conditions may reduce gradability.
A crawler tractor is among the most versatile of machines. When equipped with winch and chokers or a grapple, as shown in this picture, it can be used for yarding. Wide, low ground pressure tracks reduce soil compaction. The typical rubber-tired skidder will provide very economical yarding in a variety of silviculture prescriptions. The use of a cable winch and chokers, as shown in this picture, increases machine versatility and reduces soil compaction compared with using the same machine equipped with a grapple.
A method of commercial thinning now common is the use of a harvester-forwarder combination in what is called a cut-to-length system. The harvester moves through the stand felling, delimbing, bucking, and bunching trees selected for harvest; meanwhile a forwarder loads and moves these processed logs to the truck road where it then unloads and sorts the logs into decks for log truck pickup.
Roads, Landings, and Skid Trails Avoid Wetlands and Drainages Locate Skid Trails To Minimize Impacts Plan to Recycle Skid Trails Protect Leave Trees
Ground disturbance comparison between designated skid trails and random skid trails. In this example, random skid trails result in about 25% more ground disturbance that designated skid trails.
A rub tree is left intentionally to protect selected leave trees during harvest operations. Rub trees should be removed, from back to front, after all other logs have been removed.
Tree Selection Form Vigor Crown Ratios Spacing Wildlife Trees
Height/Diameter Ratio Intolerant species - Less than or equal to 85 Tolerant species - Less than or equal to 95
The gradual decay of wildlife reserve trees into snags.
Tree and Boundary Marking Clearly Mark Boundaries Property Line Survey Tree Marking
Harvest Timing Dry Soil Conditions to Minimize Compaction Avoid Spring Sap Flow (mid-March to mid- June) to Minimize Bark Slippage
Useful Web Sites Washington State University Cooperative Extension Oregon State University Extension USDA Forest Service Pacific Northwest Research Station Graphics, Tables, and Pictures Shamelessly Borrowed From: Creighton, J.H. and D.M. Baumgartner Wildlife ecology and forest habitat. EC1866, WSU Cooperative Extension, Pullman, WA Duncan, S Volume, value, and thinning: logs for the future. Science Findings Issue 48, USDA Forest Service, Pacific Northwest Research Station. Garland, J.J Designated skid trails minimize soil compaction. EC1110, OSU Extension Service, Corvallis, OR. Greulich, F.R., D.P. Hanley, J.F. McNeel, and D.M. Baumgartner A primer for timber harvesting. EB1316, WSU Cooperative Extension, Pullman, WA. Schlosser, W., D.M. Baumgartner, D.P. Hanley, S. Gibbs, and V. Corraro Managing your timber sale. EB1818, WSU Cooperative Extension, Pullman, WA. Stathers, R.J., T.P. Rollerson, and S.J. Mitchell Windthrow handbook for British Columbia forests. Working Paper 9401, British Columbia Ministry of Forestry, Victoria, B.C.