Determining the Economically Optimal Harvesting Age of Loblolly Pine (Pinus taeda) in Guilan Province

The aim of present study was to determine the economically optimal harvesting age of Loblolly Pine (Pinus taeda) in Guilan Province. Loblolly pine is one of the fast growing species that had successful growth in plantation at Guilan province.
For this purpose, growth data and the stumpage price of loblolly pine were used. Regression analysis was used to determine the most suitable growth model for loblolly pine.
The results showed that the best relationship between volume growth per hectare and age is a third order polynomial growth model. The equation for the price of loblolly pine stumpage was estimated based on an autoregressive model. Due to the insignificancy of this relationship at the significance level of 0.05, the average stumpage price was used for various years as an estimation of stumpage price. According to the stumpage price, annual growth and interest rate, the optimal age of loblolly pine was determined based on technical and economic criteria.
Discussion and Results showed that economically optimum harvesting age of loblolly pine varies with different discount rates.