DISTRIBUCIÓN ESPACIAL DEL CICLO DEL AGUA EN SUELOS FORESTALES CON Pinus radiata DE GALICIA (NO DE ESPAÑA)

R. CALVO DE ANTA, M.X. GÓMEZ REY

Dpto. de Edafoloxía e Química Agrícola. Fac. de Bioloxía,Univ. de Santiago de Compostela.15782-Santiago de Compostela.

Abstract

From 1997 to 1999 rainfall, infiltration and drainage waters were collected in three plots with Pinus radiata cover, located in NW Spain and having similar climate and site (physiography, plantation frame, age and height of the trees, etc…) conditions. Sampling followed natural rainfall sequences, and throughfall data was obtained at different locations with the aim to stablish the spacial variability of water inputs to the forest system. The results show the important role played by some tree species, particularly when the height of the trees is larger than 20 m, in areas with high annual precipitation ( >1500 mm). Under these conditions concentric
microsystems of soil development are generated, with intensities of effective fluxes ranging from 1000 to 15000 L m-2 y-1 increasing from the edge of the area covered by the crown to the tree trunk. In comparisson with unforested soils, the systems described here are subject to highly heteregeneous spacial and temporal evolution rythms, which alter the distribution pattern depending on felling rotations and thus on the actual location of the trees each new generation. The influence of these tree species on soil evolution is expected to increase considerably in the presence of atmospheric pollutants, taking into account the concentrating effect of the solutions derived from the leaching of intercepted rainfall.

Key words: water cicle, forest soils.