CHARACTERIZATION OF POPULATIONS OF Pseudotsuga menziesii (MIRB.) FRANCO IN CENTRAL MÉXICO. IMPLICATIONS FOR CONSERVATION

Abstract

The objective of this study was to describe the ecological conditions of 29 stands of Pseudotsuga menziesii (Mirb.) Franco located in the states of Hidalgo, Puebla and Tlaxcala, in Central México. An estimated of 9029 adult Douglas-fir trees are growing in an area of 682 ha, located in altitudes between 2450 and 3400 m on soils with slightly acidic pH, rich in organic matter and sandy loam and loam texture in most cases. The locations have a temperate climate, with an average temperatures ranging from 10.1 to 14.0 °C and annual rainfall range from 611 to 1109 mm. P. menziesii coexists with Abies eligiosa (Kunth) Schltdl. et Cham. and with several species of the genus Pinus and Quercus, facing N, NW and NE. Tree population size varies from 4 to 1450 matures trees; 11 stands have less than 100 adult trees. The natural regeneration is low in all of them, and the stands are fragmented within their natural range. Based on a cluster analysis, two clusters of stands were found: one located at Hidalgo State (Zone I), and another grouping in the Tlaxcala and Puebla (Zone II) stands. Each zone has six groups of populations. Genetic material exchange is recommended inside groups and occasionally among groups of populations to restore gene flow and encourage genetic variability. Key aspects are discussed for the conservation of these small stands.