Balance Hídrico en Tres Plantaciones de Pinus radiata I: Redistribución de las Precipitaciones (1)

Abstract

The redistribution of incident precipitation into throughfall, stemflow and interception has been investigated in three plantations of Pinus radiata D. DON: 26­ year-old (density: 733 stems/ha), 9-year old with conventional management (density: 1392 stems/ha) an 9-year-old treefarming management (density: 443 stems/ ha), near Valdivia (X Región, Chile).
Precipitación reaching the soil (throughfall plus stemflow) in the 26 year old conventional and tree-farming plantations represented 86% , 82 % and 92 % o f the incident precipitation. Interception loss was estimated to 14% , 18 % and 9% respectively, and a direct relationship between the canopy covering and the interception was found. During winter, when throughfall and stemflow increase, the absolute amounts of interception increased whereas the relative amounts decreased in the three forests.
Canopy storage capacity was estimated in 1.1 mm for the tree-farming forest, 1.3 mm for the conventional forest and 2.2 mm for the 26 - years - old forest. Required precipitation to initiate stemflow was determined to be 0.8, 1.2 and 5.2 mm in the tree-farming, conventional and adult forest, respectively.
When the density of the plantations increased, the stemflow percentages increased with respect to incident precipitation and the absolute amounts of stemflow by individual trees decreased. The amount of stemflow for individual trees was positively correlated with the magnitude area of tree crowns.