Estimation of tree and stand volume is a key calculation for productive forest
management (de Miguel et al., 2012). A precise estimation of tree volume needs to take the
variation in bole forms into account while calculation, this can be done by es
timating tree
form factor.
This study aims to construct a mathematical model to calculate the form factor of
brutia pine trees grown in the regions of Rabiaa in northern Latakia. The form factor model
can help foresters to precisely estimate the volume of tree and forest stands.
During the period 2008-2011, 72 pine trees of various ages and sizes, located in
natural stands of different densities and site qualities, were felled.
Diameters at different heights of the felled trees were measured; trees volumes and
volumes of equivalent cylinders were calculated, and consequently the values of tree form
factor were computed. The dataset was randomly split into two parts, 75% (55 trees) of the
data for constructing form factor model and 25% (17 trees) for model validation.
A form factor model was obtained using the non-linear regression equations in the
statistical program SPSS. Value of the coefficient of determination adjusted (R²adj) was
about 0.81. The model has been validated using several statistical methods, the relative
bias ( e%) was ca. 17.9%, while the value of model accuracy ) % x m ) was 22.9 %. In
order to obtain lower value of model relative bias and higher value of accuracy it’s
recommended to use a larger database comprising all distribution areas of pine in Syria.
