ESTIMATE OF STAND DENSITY INDEX FOR EUCALYPTUS UROPHYLLA USING DIFFERENT FIT METHODS

Ernani Lopes Possato,Natalino Calegario,Joyce De Almeida Alves,Gilciano Saraiva Nogueira,Elliezer De Almeida Melo

doi:10.1590/0100-67622016000500016

Abstract

ABSTRACT The Reineke stand density index (SDI) was created on 1933 and remains as target of researches due to its importance on helping decision making regarding the management of population density. Part of such works is focused on the manner by which plots were selected and methods for the fit of Reineke model parameters in order to improve the definition of SDI value for the genetic material evaluated. The present study aimed to estimate the SDI value for Eucalyptus urophylla using the Reineke model fitted by the method of linear regression (LR) and stochastic frontier analysis (SFA). The database containing pairs of data number of stems per hectare (N) and mean quadratic diameter (Dq) was selected in three intensities, containing the 8, 30 and 43 plots of greatest density, and models were fitted by LR and SFA on each selected intensities. The intensity of data selection altered slightly the estimates of parameters and SDI when comparing the fits of each method. On the other hand, the adjust method influenced the mean estimated values of slope and SDI, which corresponded to -1.863 and 740 for LR and -1.582 and 810 for SFA.

Highlights

The importance to know the growth, dynamics of canopy, mortality of trees, among other aspects interesting to the manager are strongly associated to the number of trees and their dimensions, especially their diameter
According to Reineke (1933), the stand density index (SDI) consists on the maximum number of trees per unit of area in which the stand diâmetro quadrático médio (Dq) is equal to 10 inches or 25.4 cm
When the variables were transformed by the neperian logarithm, the relationship logaritmo natural (Ln)(N)/Ln(Dq) assumed a decreasing linear behavior with the presence of a distinct upper limit corresponding to the limit of density (Figure 1)

Summary

Introduction

The importance to know the growth, dynamics of canopy, mortality of trees, among other aspects interesting to the manager are strongly associated to the number of trees and their dimensions, especially their diameter. In this sense the use of Stand Density Index is common, which reflects quantitatively the degree of trees occupation of a given area, what may be directly associated to the growth of each individual and the population as a whole (AVERY; BURKHART, 1994).

Methods

Results

Discussion

Conclusion