Effect of site quality and thinning management on the structure of holm oak forests in northeast Spain

The authors analyze the effect of site quality and thinning management on the structural heterogeneity of holm oak Quercus ilex stands at the end of the cutting cycle in different areas of the Montseny and Les Guilleries massifs (NE Spain). Height was used as an indicator of site quality, because it was relatively unaffected by thinning management, while density and total number of stems per stool were strongly affected. Mean tree diameter reflected the effect of both site quality and thinning. The type of forest management was found to be the most important factor determining forest structure. Site quality was a constraint of stand development, contributing in poor stands, to increased differences due to thinning management.