Growth of Douglas-Fir Near Equipment Trails Used for Commercial Thinning in the Oregon Coast Range; Research Paper

摘要

Soil disturbance is a visually apparent result of using heavy equipment to harvest trees. Subsequent consequences for growth of remaining trees, however, are variable and seldom quantified. We measured tree growth 7 and 11 years after thinning of trees in four stands of coast Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb. Franco)) where soil disturbance was limited by using planned skid trails, usually on dry soils. The three younger stands had responded to nitrogen fertilizer in the 4 years before thinning, but only one stand showed continued response in the subsequent 7- or 11-year period after thinning. The most consistent pattern observed was greater growth of residual trees located next to skid trails. The older stand also showed greater growth in trees located next to skid trails, whereas tillage of skid trails failed to benefit growth of nearby residual trees for the first 7 years after tillage. We conclude that traffic that compacted soil only on one side of residual trees did not reduce growth of nearby trees.