Optimal natural regeneration of Scots pine with seed trees

In this study a model for the economic optimization of natural regeneration with seed trees is presented. The objective is maximization of the present value of profits. The model is used, given an initial stand, to determine the optimal harvesting time of the initial stand, the number of seed trees, the length of seed tree period, the density of the future stand after precommercial thinning, the timing and intensities of thinnings in the future stand and the rotation age of the future stand, simultaneously. The results obtained in the numerical analysis of Scots pine (Pinus silvestris) stands in northern Sweden show that: (1) A combination of a low number of seed trees with a long seed tree period is better than a combination of a high number of seed trees with a short seed tree period; (2) The optimal density of the future stand after precommercial thinning depends on the cleaning cost function. A higher average cost of precommercial thinning leads to a denser stand after this treatment; and (3) It is economically optimal not to thin the Scots pine stand established with seed trees.1998 Academic Press