ACCURACY OF THE DIAMETER DISTRIBUTION PREDICTION OF AN UNEVEN FOREST WITH THE TRANSITION MATRIX

Abstract

This study had as main objective to evaluate the prognosis of the diameter structure utilising the transition matrix from three different measurement periods of the forest. It was also performed a comparation analysis of the prognosis generated through the transition matrix method with those obtained through the ratio of diameter movement method and the Wahlenberg’s method. The basic data were obtained from the forest reserve of the Federal University of Lavras. One hundred twenty six (126) 400 m2 plots were established in this forest. The measurements and evaluation were done in 1987m 1992 and 1996. The transition matrix method proved to be efficient for purpose of prognosticating diameter structure, independent from the measurement period, in spite of having been detected changes in the forest structure, particularly of the ingrowth and mortality rates. From the transition matrix, it was identified the existence of absorbent state in the data base. The methods of the transition matrix, ratio of diameter movement and Wahlemberg’s presented the same efficiency degree for prognosis purposes of the total number of trees. At the level of frequency by diameter class, these methods presented differentiated performance. The same fact was verified for the different evaluation periods. In this case, at least one of the methods was sensitive to changes in forest structure.