ABSTRACT
The environmental heterogeneity of a gallery forest (7.55 ha), in Itutinga, Minas Gerais State, Brazil, was characterized using the variations of chemical and physical soil proprieties, topography and canopy openness. The soil properties and topography were studied in 28 plots (10 x 30 m) that were used for the survey of the tree-shrub community. The canopy openness was investigated using two 50 m wide transects, composed by 10 x 10 m contiguous plots, crossing the forest from one side to the other, perpendicularly to the stream course. Hemispherical photographs were taken above alternate poles that delimitated the plots. Soil and topographic data were analyzed by PCA (Principal Component Analysis) and the canopy openness was analyzed by graphics of tendency and linear regression. The most important variation, in terms of soil and canopy openness, occurred with the distancing from the border of the forest and the approximation to the stream course. Following this direction, the canopy openness decreased (b = 0.096; R² = 0.34) and the soil water content and acidity increased (Axis 1 of the PCA, eigenvalue = 9.713). The largest values of canopy openness close to the border were explained by lateral light penetration through the forest border with the surrounding grassland.
Key words:
gallery forest; environment gradient; light; soil humidity