Economic investigation of advanced planting in old spruce stands | Betriebswirtschaftliche Untersuchungen zum Voranbau in Fichtenaltbeständen

The paper presents an investigation on the restructuring of pure coniferous stands into broadleaved and mixed stands. The investigation is applied to an about 80 years old spruce stand to be harvested and restructured within the next 40 years. Six different forest management concepts are applied to the stand using a growth model. Each management concept aims to regenerate the spruce stand with broadleaved trees or with a mixture of broadleaved trees and conifers. The concepts differ as regards the time and way broadleaved trees are planted. Either broadleaved trees are planted advanced in the spruce stand of which the density index was reduced in order to let more sunlight reach the young plants. 15 or 30 years later the plantation will be a young copse and the stand will be harvested. Or broadleaved trees are planted on cleared area after harvesting the entire spruce stand. Proceeds and harvesting costs from simulation and planting costs enter the economic assessment. By reducing the density index of the old spruce stand the risk of storm-caused damage rises in comparison to the variants without advanced planting. The probabilities of survival that express the different risk of storm-caused damage due to different forest management measures are considered. The concepts are compared with their expected value of net present value. Four different interest rates are applied: 0, 1, 1.5 and 2 %. The impacts of the management concepts on stand development and the expected values of net present value are simulated by special models. Different planting costs are considered. Finally, the impacts of changing wood prices and harvesting costs on the expected values of net present value are investigated. It is shown that, in spite of increment reduction and rising storm damage risk due to reduced stand density, advanced planting concepts are more appropriate. This is due to the lower planting costs for advanced plantings and the fact, that first returns, as part of reducing stand density, are only slightly reduced when entering the expected value of net present value on account of the short discounting period. Distinctly lower planting costs for all concepts may offset the advantage of the concepts without stand density reduction.