Estimate of Stand Density Index for Eucalyptus Urophylla Using Different Fit Methods

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. 922Revista Árvore, Viçosa-MG, v.40, n.5, p.921-929, 2016 POSSATO, E.L. et al.

Aspectos metodológicos para generar diagramas de manejo de la densidad de rodales con base en el índice de Reineke

“…La información dasométrica que se usa en la gran mayoría de los trabajos clásicos de densidad para delimitar la línea de densidad máxima y para construir un DMD debe, preferentemente, proceder de parcelas experimentales permanentes, ubicadas en rodales con densidad y competencia extremas; una red de parcelas de este tipo permite monitorear, en el tiempo, el comportamiento tanto del cierre de copas como de la ocurrencia de períodos de mortalidad (Weller, 1987;Zeide, 1987); sin embargo, por la planeación a largo plazo, los costos implicados y el tiempo que se requiere para el establecimiento y monitoreo de la red es difícil disponer de información dasométrica suficiente en forma de series de tiempo completas, en el corto y mediano plazo (Pretzsch, 2006;Condés et al, 2017). En algunos estudios recientes de densidad, se utilizan técnicas de ajuste novedosas tales como funciones frontera, en las que usan 10 toda la información disponible procedente de sitios de muestreo o de parcelas temporales (Lopes et al, 2016;Quiñonez et al, 2018;Salas y Weiskittel, 2018).…”

Using Limit Value Constraint Theory to Better Understand the Self-Thinning Rule of Forest

“…Moreover, there have also been some reports that indicate that the maximum stand carrying capacity is related to climate change [2,34,35] and thus varies depending on site conditions [1,36,37]. For a given tree species, in addition, different data and methods used to obtain this parameter may lead to variable values of the slope parameter [19,20,29,[38][39][40][41][42][43].…”