Silvicultural and financial analysis of three case studies in the Oregon Coast Range

Graduation date: 1995Three data sets were examined to determine the costs with and without\ud constrained forest management practices. Two adjacent sites in the Coast Range of\ud Oregon were studied. One of the units was broadcast burned while the adjacent site was\ud left unburned. The stands were projected for growth and yield in the Douglas-Fir\ud Simulator (DFSIM) and Oregon Growth and Yield Projection System (ORGANON). For\ud the simulations a 70 year rotation at 4% interest was used. The total timber volume\ud differed by (1-4%) with the higher volume on the burned unit. Soil expectation value was\ud 4% ($400) higher on the burned unit.\ud Black Rock plot 31, a stand of conifers, was analyzed for retention of various\ud amounts of overstory Douglas-fir trees with an understory of hemlock. Eight different\ud rotations of varying amounts of retained green trees and rotation lengths were forecast\ud with ORGANON. The lowest opportunity cost was realized on the shorter rotation when\ud two trees were left in the overstory and understory hemlocks were pre-commercially\ud thinned. Forest weeding in the first two years of plantations was analyzed at four sites of\ud increasing site index. DFSIM and the stand projection system (SPS) were used to project\ud two different thinning regimes on weeded and non-weeded sites. Weeded sites produced\ud consistently higher timber yields. Thinning to 100 trees per acre (TPA) produced higher\ud yields on the weeded sites and thinning to 150 TPA produced higher yields on non-weeded\ud sites. All weeded sites produced higher value stands ranging between (5-75%).\ud The most pronounced weeding value difference was at the low productivity site and the\ud least value difference was at the high productivity site