Abstract

A 12-year-old Eucalyptus globulus plantation forest was studied with the aim of assessing and modeling the effect of both pruning and thinning activities on the growth strain. The stand is located in the Andean foothills of Bio Bio region in Chile. Two forest management activities were carried out after 2 and half years from planting, and were evaluated according to different pruning intensities (from 0 to 60 % from total height of the tree) and different thinning densities (800 UPH with thinning and 1.600 UPH without thinning). Furthermore, the effect of the crown classes (dominant, co-dominant and intermediate crown) was studied by the combination of two treatments on the behavior of the growth strain. Each treatment was defined by two levels of pruning and thinning. Data at single-tree level were collected to each sampling unit for estimating the most relevant parameter for the stand. Thirty-three trees in total were sampled. The growth strain was measured at the dbh in each one of them, with an extensometer designed by the CIRAD-Foret. The pruning and thinning did not significantly affect the behavior of the growth strain in Eucalyptus globulus according to the research study; on the other hand, the crown class had a highly significant affect on the variation of strains, showing the highest levels of it in dominant crown class trees that trees belonging to co-dominant and intermediate crown classes, respectively. The logarithmic functions and the variance obtained by measurements of dbh, crown radii, and pruning respectively, were entered into regression models as predictor variables of behavior of growth strain, showing a R-2 0,44 and a SEE 0,132.