Optimising stand management on peatlands: the case of northern Finland
2012
Ahtikoski, Anssi | Salminen, Hannu | Hökkä, Hannu | Kojola, Soili | Penttilä, Timo
Peatland forests constitute a significant timber resource in several boreal countries. In Finland, peatlands have been intensively managed with large-scale drainage operations to enhance growth of the stands. In comparison with forests on mineral soils, a divergent feature in the management of peatland stands is the ditch network maintenance. We investigated the optimal forest management schedules for peatland stands using data from 17 Scots pine (Pinus sylvestris L.) sample stands representing the most important drained peatland site type in two climatic regions in northern Finland. We used the PIKAIA optimisation procedure (a genetic algorithm) to maximise the net present value of alternative management schedules involving ditch network maintenance operations and thinnings. Recent price and cost data were applied in the analyses. We found that the higher the interest rate, (i) the shorter the present generation’s rotation period and (ii) the less silvicultural activities were involved in the management schedule. Harsh climatic conditions emphasised this result, also showing that a decrease in the mean annual increment may lead to a significant increase in net present value. For each individual stand, the optimal stand management clearly outperformed (with respect to financial outcome) reference management that was mainly based on prevailing silvicultural recommendations. The results highlight the importance of interest rates in financial analyses of forestry: it is not self-evident that optimal stand management would include several silvicultural activities, such as ditch network maintenance and thinnings.
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