Profitability of alternative management regimes in Scots pine stands on drained peatlands.

In drained, forested peatlands, ditch network maintenance (DNM) is often considered necessary for tree growth, but it also constitutes additional management costs. Commercial thinnings, in turn, in addition to their silvicultural benefits, are generally applied to enhance the financial performance of stand management but results from peatland stands are scarce. In this study, our aim was to find financially feasible management practices for Scots pine-dominated stands on drained peatland sites in Finland. Using mainly inventory data sets, we compiled altogether 29 typical model-stands for four climatic areas, four site types, and two stand conditions according to need for silvicultural care. We used MOTTI stand simulator to predict the development of the model-stands according to different management regimes consisting of various combinations of 0-2 DNM and 0-2 thinnings with different timings and thinning intensities. We then calculated and compared the financial feasibility of the regimes using net present value (NPV; discount rate 3%) analysis. The separate effect of DNM on the profitability was marginal, but the positive effect of thinnings was clear. The harvesting removals varied within a wide range, depending on the timing and intensity of thinnings, but on average, the NPV doubled due to the thinnings. In the stands of initially good silvicultural condition, regimes including only one thinning and a DNM operation generally displayed a good financial result. In the stands of initially poor silvicultural condition due to neglected early care, regimes with two thinnings produced the best NPV regardless of the often low-yielding first thinning. [ABSTRACT FROM AUTHOR]