Prices of timber sales in the intermediate harvest in Scots pine stands depending on their age

The research concerned the implementation of tasks in the field of harvesting timber in 2008-2012 in pure pine stands aged 10-140. Numerical data from the SILP database were used for calculating the average price of timber in the intermediate harvest. The data on the volume harvested covered late cleaning, early thinning and late thinning. The assortment structure concerned the following groups of large- (WA0, WA1, WB0, WB1, WC0, WC1 and WD), medium- (S10, S11, S2A, S2B, S3A, S3B and S4) as well as small-sized (M1 and M2) assortment groups. The data on the size and value of wood assortments sold across the country concerned the year 2011 and were used to calculate the average price of wood in age subclasses according to the site quality described with site index class. Subsequently, for each site quality class polynomial equations of the trend line was determined and average timber price for each age subclass was calculated for small-, medium- and large-sized assortments. The analysis showed that S2 is the most frequently harvested assortment in the intermediate cuts in Scots pine stands, whose share depending on the site quality class is at the level of 65.7-72.7% of total harvest. The share of small-sized assortments decreases with age in all site quality classes. The opposite tendency is seen for large-sized assortments, whose share decreases with the deterioration of the site quality. Fraction of medium-sized assortments reaches its peak at the age of ca 45 in IA site index class and the shift in the peak with age is associated with the deterioration of the site quality. The higher the site quality, the higher the prices of assortments in the intermediate harvest. This trend occurs in all age subclasses.