Comparison of Spatially Constrained Harvest Scheduling and a Classic Allowable Cut Indicator Approach for a Strip Shelterwood System

Abstract

Forest management changed markedly in the Czech Republic and Slovakia after 1989. Following the denationalization of forestlands, forest managers became more concerned about sustainable timber production and the environmental impact of harvest operations. Current national forest laws in both countries prescribe a shelterwood silvicultural system, but clear-cutting according to harvest scheduling by allowable cut indicators is still the most widely used management system. As an alternative to allowable cut indicators, we investigate spatially constrained harvest scheduling under a shelterwood system. Our study design considers both spatial and non-spatial constraints. The first spatial constraint concerns adjacency—managers cannot simultaneously harvest trees from adjacent areas. The second is an environmental requirement to reserve a specific portion of the stand. Non-spatial constraints include factors such as the upper limit of harvest determined by an owner’s harvest flow requirements. We developed and compared three alternatives, which employ different constraints to investigate their respective influence. We used integer programming to find the optimal solution for each alternative under spatially constrained harvest scheduling and compared these results with the allowable cut indicators method. Our results showed that total net present value is smaller for the alternative with a reserve constraint and even flow harvest requirements. Moreover, in each simulation period, this alternative consistently minimized the difference in volume derived between the spatially constrained and allowable cut harvest scheduling systems. The difference in total cut and total net present value between the two harvest scheduling systems was 0.34% and 2.33%, respectively.