Determination of growing stock in fir stands by using tree distances method

Forest inventory in Turkey is realized by finding the sample points in the field, position of which are determined on the map initially. After finding these points in the field, measurements and observations are realized in the sample plots, size of which change based on stand closure. Borders of these circular sample plots are determined by using ropes length of which are determined based on the radius of the representative circles. Inventory is the most labour, time and money consuming stage of the forest planning studies and researches on more rational methods have to be realized. For this reason, experimentation of tree distances method in a forest area in Düzce region and comparison of the results with the data obtained from the samplings in 400m² circular sample plots is aimed. Generally, 6 trees are used for tree distances sampling. The size of the sample plots in tree distances method is determined by 10 neighbour trees to the centre tree. To realize the study both the tree distances method and circular sampling (400 m²) is realized at each sample point. The volume of the sample plots are found by summing the volume of each single tree in the plot. Single-entry volume tables for the region were used to find the volume of trees. The size of the sample plots in tree distances method was determined by separately measuring the distances of each neighbour tree to centre. It was aimed to determine the method in which the least number of trees were measured, and the method number 3 in which the neighboring 3 trees were applied gave similar results with the 400 m² sample area method. It is seen that increasing number of trees also increased the accuracy when the methods are generally evaluated. Methods 3, 17, 21 and 23 come into front based on all the trees adjacent to the central tree.