This study aims to construct a mathematical model to calculate the form factor of
Palestine Oak Maquis grown on the eastern versants of coastal mountains. The form factor
model can help foresters to precisely estimate the volume of tree and forest
stands.
In the year 2014, 129 oak shoots of various ages and sizes, located in natural stands
of different densities and site qualities covering all conditions of region grown on, were
felled.
Diameters at different heights of the felled shoots were measured; shoots volumes
and volumes of equivalent cylinders were calculated, and consequently the values of shoot
form factor were computed. The dataset was randomly split into two parts, 70% (90
shoots) of the data for constructing form factor model and 30% (39 trees) for model
validation.
Several form factor models were developed using the non-linear regression equations
in the statistical program SPSS. Best fit to the data was selected and value of the
coefficient of determination adjusted (R²adj) was about 0.77. The model has been validated
using several statistical methods, the relative bias of the best model ( e%) was ca. -3.6 %,
while the value of model accuracy ) % x m ) was 15%. 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 oak Maquis in Syria.
This research aims to studying the plant species diversity in the
oak Maquis at the Eastern versants of the coastal mountains in
Syria, and tries to identify the most important factors affecting this
diversity.
