Abstract
This experiment has been carried out in Aqrai, Atroosh and Zawita zone on stand of Pinus brutia Ten. In Northern of Iraqi to determinate on accumulation the effect of density between trees for the growth of basal area for the length of rotation of trees. Different types of measurements have been taken for (30) random samples with an area of (0.1) ha. Measurement cover basal area , mean height and number of tree per hectare , by using different regression in statgraf system to derive mathematical equations. In order to select on equation that give the best fit , the following criteria were employed in the evolution process coefficient of determination R2 , standard error (S.E) , a mathematical relation between basal areas in the hectare as , dependent variable , on the other hand , age ,number of the tree in hectare , mean height as independent variable , we obtain the following equation:
G=-2.6559+2.08333 A (1-e (-0.001020N))
Culmination of basal area length cutting cycle of Pinus brutia Ten. in Iraqi was estimated by using the equation above,we found increasing for growth basal area, when the number of tree increase to (750) tree| ha and age year. While the annual basal area growth was deceased, when the number of tree increased. From that the manager can select the best number and age which, he wanted in the produced of the stand Pinus brutia Ten.
