Stemflow in different forest fragments of Ipanema National Forest in Iperó, Brazil.

Stemflow (Et) corresponds to the fraction of the rain that, after being retained by the canopy, flows over the branches and trunks to the soil surface, which is very important for rainfall water redistribution. This study quantified and compared the Et in relation to the total precipitation (P) of three forest stands (Eucalyptus cloeziana, Pinus sp. and a semi deciduous Forest Fragment (FES)), thus providing information for planning of the future hydrological monitoring of lpanema National Forest in IperO, Brazil. In each stand, a 300m2 plot was established, containing ten Et collectors and a rain gauge installed next to each plot. A total of 25 observations were analyzed and it was found that: the Et values were 1.0% in the FES, E. cloeziana and Pinus sp. of P, furthermore, Et starts when P is equal to or greater than 11.0 mm, 6.6 mm and 8.2 mm, respectively. This shows that at P values lower than these, water does not reach the soil by the stemflow process, and is returned to the atmosphere by evaporation or directly dripping on the ground. A positive correlation between the canopy retention capacity and its area was found. Vegetation has a great influence on the rainwater redistribution by directing the droplets that reach the ground with less impact. This affects the water supply to the underground water reservoir and contributes to the maintenance of the chemical and biological soil system.