Modelling silvicultural and economic alternatives for Scots pine (Pinus sylvestris L.) plantations in north-western Spain

Two silvicultural alternatives for Scots pine (Pinus sylvestris L.) plantations in north-western Spain were simulated and compared. One corresponded to the current management practice applied in the region and the other was an intensive silvicultural regime. Both alternatives were described by a specific combination of plantation density, precommercial treatments, thinning pattern and rotation age. Stand development of each silvicultural alternative was generated using a regional growth and yield model implemented in a simulator called GesMO, for three site qualities that represented poorest, intermediate and best sites found in the region. Different timber grades associated with each alternative were predicted, and estimates of costs and selling prices were used to predict a cash flow pattern for each of the simulated alternatives. The alternatives were ranked using the criterion of net present value of an infinite series of rotations. Sensitivity analysis, in terms of basic prices, discount rate and rotation length, was also carried out. In addition, the effects of risk of fire on net revenues were evaluated. For the present regional market conditions the results showed that the currently applied alternative is not the best one if the main aim is profit maximization. For very poor quality sites the proposed schedules are uneconomical for all silvicultural alternatives.