Disturbance, age and size structure in stands of Pinus uncinata Ram

Abstract

The size and age structure of two subalpine conifer pure stands of Pinus uncinata were examined and interpreted using a simple classification of trees by crown exposure to direct sunlight. Both populations show irregular reverse-J shaped diameter distributions having an uncertain Interpretation. However, peaks in the age distribution of both stands and the crown exposure of the youngest ones clearly reveal that regeneration occurs in forest clearings. Tree-ring width series from each stand were used to reconstruct their recent disturbance history through the identification of growth releases. Disturbance regimes in the analyzed stands are different, but they show an analogues shaping effect on the age structure in both cases.