Influence of wind and native vegetation on the distribution of Pseudotsuga menziesii

Abstract

Sapling distribution patterns of wind dispersed species tend to be influenced not only by wind direction and speed, but also by the presence of shrubs species that favor sapling recruitment. We analyzed the effect of wind direction and presence of understory species in Austrocedrus chilensis forest and shrublands, on Pseudotsuga menziesii sapling distribution. We selected three P. menziesii forestations; in each forestation, six transects were established in NE, E, SE, SW, W, NW orientations. Pseudotsuga menziesii seedling and sapling densities were evaluated in each transect. Understory species associated with P. menziesii saplings were also recorded. We found significant difference in P. menziesii sapling density between wind-favored versus non-favored orientations, being more abundant in wind-favored orientations. We also detected significant differences in P. menziesii saplings density associated with different understory species and herbaceous species or bare soil; the highest values were found in association with herbaceous species or with bare soil.