Least-cost allocation of measures to increase the amount of coarse woody debris in forest estates

Coarse woody debris (CWD) is crucial for maintaining biodiversity in forests but conservation measures to increase CWD must be performed cost efficiently. We estimate least-cost combinations of CWD-increasing measures in a spruce-dominated Swedish forest estate. Specifically, we investigate how using combinations of the measures tree retention, creating high stumps, manual scarification, prolonged rotations, and retention of dying trees impacts the amount of CWD and net present value at the estate level. We found that by combining CWD-increasing measures in an optimal way the amount of CWD on the estate could be increased 322% with a decrease in present value of only 10%. The optimal combination of conservation measures depends on the desired increase in CWD. The analysis thus shows that huge improvements in cost-efficiency of biodiversity-oriented forestry are possible.