GROWTH AND CROWN TRAITS OF PROVENANCES OF Pinus greggii Engelm. AT GALEANA, NUEVO LEÓN

Abstract

Pinus greggii Engelm. natural populations grow in small groups isolated by geographical barriers; this condition limits the genetic exchange among them, thus allowing to suppose important genetic differences among populations. The research assessed survival, growth and canopy characteristics in nine provenances of Pinus greggii trees after 4.5 years of plantation, at Galeana, Nuevo León, México. Measurements were done in 2004, considering survival, height, stem base diameter, first branch height, and canopy diameter (N-S, E-W); in addition, variables such as canopy diameter average, canopy projection area, light interception area and tree canopy average, were calculated. Statistical differences (P ≤ 0.05) among provenances were found for all variables, except survival. The provenance with the highest tree height reached 136.5 cm, with a canopy projection area of 0.85 m². Light interception area varied in more than 1.1 m² among provenances. The canopy characteristics were linked to growth rate differences in provenances. Tree height correlated with provenance altitude (r= - 0.76), as well as light interception area (r = 0.94), canopy projection area (r = 0.86) and canopy average (r = 0.48). According to this study, the trees from Los Lirios, Coahuila and Agua Fría, Nuevo León should be best yo protect the soil in the plantation sites.