Effect of harvest interval and intensity on the profitability of uneven-aged management of Norway spruce stands

This study evaluates the profitability of uneven-aged management in boreal forests, focusing on Norway spruce (Picea abies (L.) Karst.). An individual-tree-based model EFIMOD is used to simulate the dynamics of soil organic matter, resource availability and forest growth. Considered management scenarios are constructed by varying the harvest interval and intensity (i. e. post-harvest basal area). Bare land, young stand and several uneven-aged managed mature stands are evaluated as initial stand states in the profitability analysis. The profitability of uneven-aged management is compared with traditional even-aged management. Uneven-aged management is profitable under all considered initial stand states and management scenarios with 3 per cent interest rate. Even-aged management is more profitable than uneven-aged management when the initial stand state is bare land or a young stand. The profitability is usually the opposite when uneven-aged managed mature stands are considered as the initial state. This, however, requires that the most profitable steady-state management regime, involving a 10-year harvest interval and 4m2 ha-1 postharvest basal area, is applied. Conversion of even-aged Norway spruce stand to uneven-aged is financially feasible when the stand structure of the even-aged stand has a wide diameter distribution of standing trees rather than the more restricted range usually associated with conventional management using thinning from below.