Optimizing continuous cover and rotation forestry in mixed-species boreal forests
01/05/2020
We study the management of mixed-species boreal forests and tree species composition in a stand-level economic-ecological, size-structured model. The model includes ecological tree species interaction, a detailed harvesting cost module, optimal harvest timing, and optimization between continuous cover and rotation forestry. Optimization is solved applying a tri-level structure, in which the optimal rotation is the highest-level, harvest timing the middle-level, and thinning intensity the lowest-level problem. Given realistic regeneration costs and a 3% interest rate, continuous cover forestry is optimal and may include up to a 40% fraction of broadleaves. A low interest rate and low regeneration cost together with the presence of light-demanding Scots pine favours rotation forestry. Eurasian aspen decreases the bare land value but is optimal to fell without utilization only when it has no commercial value. Overyielding in terms of cubic metre output does not reveal the economically preferable species combination. Managing single-species stands by removing naturally regenerated other species decreases the economic outcome by 35-44%. Felling noncommercial trees without utilization shows that the economically optimal solution avoids “high-grading”. Maintaining the number of large-diameter trees beyond the level that maximize profitability implies only minor losses. Omitting thinning decreases the bare land value up to 73%.
Mixed Boreal Harvesting Economics Stand Structure