Soil-site productivity of Gmelina arborea, Eucalyptus urophylla and Eucalyptus grandis forest plantations in western Venezuela

Commercial forest plantations have become a competitive alternative to harvesting natural forests in many parts of the world, especially in the tropics and sub-tropics. More research about tree farm site selection is needed, and one of the major considerations of site selection is the site's productivity. The purpose of this research was to explore the soil factors that are indicators of site productivity. A study was conducted in a dry tropical region of western Venezuela on Gmelina arborea, Eucalyptus urophylla, and Eucalyptus grandis plantations to identify the soil properties that provide optimum growing conditions for these species. Results of a multiple regression analysis indicated that soil texture was a significant predictor of tree growth for all three species. All species grew best in soils with clay loam textures. Excessive soil moisture was inversely correlated with tree growth in Eucalyptus grandis. As commercial forestry companies in western Venezuela expand their land holdings through new acquisitions, this knowledge will improve their ability to select land parcels that are economically optimal for plantation purposes. (C) 2001 Elsevier Science B.V. All rights reserved.