PROYECCIONES DIAMÉTRICAS DE BOSQUES TEMPLADOS DE DURANGO, MÉXICO

Abstract

The purpose of this research study was to simulate diameter structures of native coniferous forests of Central Durango, Mexico with the application of diameter growth models, the diameter structures of standing remnant and harvested trees. From harvesting records and forest inventory we extracted and modeled diameter structures of standing remnant and harvested trees of three ejidos of the El Salto Region of Durango, Mexico. Diameter structures were modeled by the Weibull probability density function. A growth model predicted diameter increment of remaining trees. We simulated two different ways of harvesting trees: a) by simulating what it has been done in the harvesting records and b) by simulating harvesting according and proportional to the present diameter structures of standing trees. Eight different harvesting intensities were simulated, from 5 to 40% of the volume per ha and the simulation was stopped when standing volume remains constant between harvesting operations. The results of these simulations indicate that continued harvesting simulating the previous records would reduce the diameter structure variation on the right hand side and displace the mode to the right hand side of the diameter distribution. This pattern is noted primarily when harvesting is greater than 20% of the standing volume. When har;,esting is conducted proportionally to the current diameter structures, longer time, up to 10 years, is required to attain the diameter structures in contrast to when it is harvested according to previous records. Therefore, the recommendation is to harvest trees with an intensity between 20 to 25% proportionally to the present diameter structures and the lag time between harvesting operations should last between 18 to 24 years.