Fir (Abies hickelii Flous & Gaussen) forest structure variation in relation to environmental factor on the Orizaba Peak, Mexico

Abstract

This study was conducted near the ejido Jacal, Calcahualco, Veracruz, in the fir forests of the Pico de Orizaba National Park. the structural changes along an altitudinal gradient, and their relation to environmental factors (relief, soil and temperature) were studied. On each of four physiognomic variants previously distinguished, vegetation samples were taken with the point-centered quarter method. Soil samples were taken and temperature was recorded. The data was processed with the ordination program CANOCO. The structural changes in the fir forest are associated to a complex gradient formed by altitude, temperature, soil depth and different chemical characteristics.