Production rates and costs for skyline harvesting were examined over a range of residual thinning intensities, operational methods, and sites. The sites included three stands of 40- to 50-yr-old Douglas-fir on the Willamette National Forest in the Cascade Mountains of Oregon. Three silvicultural treatments were studied at two sites, and...
In western Oregon, hardwood trees occupy 20% of the
timberland but account for less than 1% of the timber
harvest. Information about how to manage them effectively
is limited.
The objective of this study was to examine: 1)
effect of thinning on tree growth, plant moisture stress,
and crown cover...
On-the-ground harvest unit layout, especially in skyline-thinning operations, is critical to meeting multiple resource objectives of the land manager and maintaining the economic viability of the timber harvesting operator. This phase of an operation can optimize the layout and harvesting of a sale or unit. Detailed layout by a knowledgeable...
Harvesting costs were determined for commercial thinning of young stands to
achieve vegetation and wildlife objectives. This included replicated comparisons of
thinning treatments. Treatments were defined based on residual tree stocking after
thinning. Study procedures were developed and evaluated to improve statistical
relevance. Multiple linear regression models were used to...
A 20-year-old Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] stand in the Oregon Coast Range was thinned from about 1,700 to about 350 trees/ac. Subsequent thinnings, under eight different regimes, occurred at ages 23, 27, 30, and 32. Average net periodic cubic-volume growth was strongly influenced by thinning regime, varying from about...
The purpose of this study was to determine if thinning, fertilization or a combination of thinning and fertilization had an effect on overall average specific gravity, modulus of elasticity, modulus of rupture, fiber length and intra-ring characteristics. Material for this experiment consisted of 7 trees randomly selected from each of...
Thinning is one of the most powerful forest management tools available to landowners for achieving a wide range of goals and objectives.
Thinning influences:
• Trees’ growth rates and potential economic value
• Which species of trees and other plants will be in the stand
• Trees’ resistance to insects...
This paper describes methods that can be used to
evaluate stand and tree growth response to a single
application of fertilization and/or thinning with data
collected from multiple installations. Two kinds of
methods were proposed: (1) structure analysis which
applies covariance analysis in a blocked design with and
without sampling...
The algorithm RLS-PLUS was developed to yield solutions to the
multivariate control problem of diameter and species optimization for mixed conifer
and hardwood stands. The problem is specified with twenty-five state variables
consisting of five species groups with four merchantable diameter classes and one
unmerchantable class. This gives twenty diameter...