Impact of Scots pine stand growing stock on determining the optimal economic rotation age

The stand volume is one of the forest inventory characteristic determined during the field work aimed at planning operations in the tree stands. Determining the optimal rotation age is an important decision issue in the forest management. In turn, the key factor that determines the choice of the method for determining the rotation age of the tree stands is the production target. Depending on the rotation age, a specific structure of quantity, quality and dimensions of particular timber assortments is obtained. It seems reasonable that the economic rotation age is one of the main criteria taken into account when planning forest management in tree stands or forest district. The aim of the paper is to assess the impact of growing stock on determining the rotation age of Scots pine stands in particular site index classes. We compared the tabular (i.e. based on data from yield tables) and real (i.e. based on data from the Information System of the State Forests) volume of pine stands. The analysis was based on the forest description data, the amount of the harvested timber and economic data: timber price as well as the costs of harvesting, skidding and production of assortments. The optimal economic rotation age was determined as the point of intersection of the curve describing the average and current increment of the value of Scots pine stands. The research showed that the rotation age of stands is related to the site index class and whether real or tabular results are analysed. The optimal rotation age for Scots pine tree stands is lower in the real data model from 10 to 23 years from that calculated on the basis of tabular data.