Continuous cover forest management decreases nutrient loads to water courses

Abstract This study looked at the effects of even-aged forest management (BAU), continuous cover forestry (CCF), and any-aged forestry (AAF) on the loads of phosphorus and nitrogen to downstream water bodies when these loads were minimized by forest planning. The impact of aiming at minimal nutrient loads instead of maximal economic profit was inspected within each of the three silvicultural systems. The analyses were conducted with and without even-flow-cutting constraints. The data for the calculations was a random sample of forest stands, representing two municipalities in North Karelia, eastern Finland. The results showed that the transport of nitrogen and phosphorus from managed commercial forests to water courses can be substantially reduced by increased use of continuous cover forestry. Significant reductions were possible in both peatland forests and mineral sois. Nutrient loads could be reduced also in even-aged BAU management by decreasing the use of clear-felling, particularly in spruce mires. Nutrient loads increased with increasing harvests in all silvicultural systems. Significant reductions in nutrient loads can be achieved with a reasonably small loss in the profitability of forest management. Optimal use of continuous cover management makes it possible to simultaneously increase economic profitability and decrease nutrient loads.