Geoecological Investigations on the Timberline of Pico De Orizaba, Mexico

Abstract

Measurements of soil temperature, soil moisture, and surface temperature were carried out at different elevations on Pico de Orizaba, Mexico, in order to evaluate the ecology (phenology, plant physiology, and surface fire impact) of the local plant growth near the upper timberline. The lack of dense, dwarfed tree stands above the timberline seems to be a result of natural and man-made fire. The main limiting factor to tree growth is low soil temperature in spring, which limits water diffusion through plant cell membranes (“cold-dry limit”).