SITE INDEX AND SOIL PROPERTIES IN YOUNG PLANTATIONS OF Eucalyptus grandis AND E. urophylla IN SOUTHEASTERN MEXICO

Research on the ability of tropical soils to support fast-growing forests species is required to optimize, preserve and select lands for timber production. fit this work site index (SI) of Eucalyptus grandis and E. urophylla plantations in Southeastern Mexico, was related to chemical and physical soil properties. Based on a joint model of SI vs. sand content, the fit suggests that SI improves as the sand content increases (p <= 0.01). Sand content of 28% in the surface soil (0-5 em) and 24% fit the sub-surface soil (5-30 cm) is a desired minimum for establishing highly productive stands. The best SI conditions were found on sandy soils with a sand content of 65 %. Other variables, such as soil bulk density, N mineralization and organic matter were also measured but were not correlated with stand growth or SI. Cation exchange capacity was inversely related to tree growth, which was explained as an indirect relationship since soil with higher content of fine soil particles (clay+silt) were less productive.