Prognosis of the diametric distribution of tree species with the transition matrix and movement ratio methods

Abstract

Research is needed to subsidize foresters to manage the forest for better use of wood. To help in the research, analyzing the diameter distribution, the species can be grouped according to their characteristics concerning the diameter growth and projected their future growth, determining if they reached the expected diameter before the cutting cycle stipulated by law. The aim of the present research was to diametric distribution predict by a size class distribution method, by ecological groups. The study was carried out in Moju, PA. Nine clearings were selected, around which 4 sample plots of 10 x 50 m were installed, starting at the border of the clearing into the forest in the north, south, east and west directions. All individuals with DBH (diameter at breast height) ≥ 5 cm were measured. The species were grouped into tolerant, intermediate and intolerant regarding the demand for solar radiation. The methods tested were Transition Matrix and Moving Ratio, using data from 1998 and 2001 and making projections for 3 year periods (2007 and 2010). The efficiency of the projections was tested using the Kolgomorov-Smirnov adhesion test. The projections performed by the methods did not present a significant difference between the actual and projected values. Based on the results it is recommended to use the Transition Matrix for the prognosis of the diametrical distribution of individuals belonging to the group of tolerant and intermediate species and it is indicated to use both methods for intolerant species.