Aspectos estructurales, composición florística y caracterización ecológica del bosque de oyamel de la sierra de zapalinamé, Coahuila, México

Abstract

The sierra de Zapalinamé lies at the southeastern portion of the State of Coahuila, in a transitional area between the Chihuahuan Desert Region and the Sierra Madre Oriental. It has the status of a protected natural area by the state government. The Chihuahuan desert scrub is the most common vegetation type; however, spruce forest grows where the climate conditions are cold and temperate. Ten circular plots of 1,000 m2 were established to determine the floristic composition, structure of the forest and other ecological variables. Diameter and height were measured for every tree and shrubs and herbs were recorded. Seedlings were evaluated in five plots of 2 m2 per site. Attributes of the vegetation like density, basal area and the importance value of the tree species were estimated. The spruce forest of the sierra de Zapalinamé is found between 2,668 to 3,025 m of elevation where the annual average precipitation rain varies from 560 to 600 mm and with a temperature of 12.5°C, over litosol soils with a slope of 34% to 70%. The forest is dominated by Abies vejarii, species which grows at elevated places and another important species is Pseudotsuga menziesii. Regeneration is of a few seedlings; nevertheless, due to microclime and soil some regeneration is successful. A total 73 species were recorded in these forests, being the most diverse Asteraceae (15 species), Pinaceae (4) and Poaceae (4). Conservation of the spruce forest is important due to its ecological value; in addition Abies vejarii is listed under status of conservation in the Mexican red list, and also because a number endemic species of plants are in this protected area.