Matrix Growth Models for a Natural Forest in Shasha Forest Reserve Nigeria

Abstract

Matrix growth models were developed for a natural forest stand in Shasha forest reserve Nigeria. Data were collected from permanent sample plots in the forest in 2006 and 2012 by complete enumeration of trees with a minimum diameter of 5cm at breast height. All observed trees were classified into three species groups; top, middle, and under storey species. Within each species group, trees were classified into diameter classes with a width of 5cm. Linear regressions were used to estimate the ingrowth, mortality and upgrowth transition probabilities for a six year growth period. The models were developed, calibrated and validated with data from the permanent sample plots. Simulations suggested a recovery in the tree population of the forest stand given minimal disturbances. Validation of the models gave reliable predictions of stand population and diameter distributions for the forest. The x² statistics for the species groups revealed no significant differences between the predicted and observed number of trees at 0.05 significance level. The models provided some vital information which can be employed for sustainable management of the natural forest.

Keywords: Matrix models, Transition probabilities, Diameter distribution, Forest dynamics, Forest management