Abstract
Growth function were use for estimating the basal area and volume per hectare of Populus nigra stands Zakho Region, data have been collected from(45) random samples, each area of the sample was ( 0.1) per hectare. The characteristics of each sample were measured , the samples cover different ages and densities of Populus nigra stand . By using four mathematical models and differentiation among them depending upon statistical measurements, we have got the following equation:
G = -1.597 +3.395(H) – 80.72(1000/N)
The coefficient of determination was (0.86 ) and standard error percent of the mean (3.18 ). This equation was check for a good fitting of basal area per hectare for Populus nigra , and it was used for preparing a basal area table depending on height and number of trees. The integration of the equation of basal area are extremities which lead to the following:
V = 148.045 – 1.59(1000/N) + 3.394(H)(1000/N) - 40.36(1000/N)2
A table was prepared form the equation to estimate production for unit area at specific density and height.
