Ecological Structure and Wood Volume of Prosopis Species (Mesquite) Communities in Northeast of Mexico

Abstract

The Mexican Gulf coast is characterized by dry regions with high variations in climatic conditions, rich in drought-tolerant or subhumid species, and including multipurpose trees (MPTs) and shrubs, which have more than one substantial contribution such as products or service functions to the land-use systems in which they are grown. This chapter aims to introduce the lecturer with ecological characterization and forest productivity of the mesquite scrub and woodland, their diverse uses as MPTs and shrubs of tropical and subtropical areas of semiarid zones of northeastern Mexico. 70In three physiographic zones, 30 sampling sites were randomly selected, based on cartographic material and digital ortophotos where mesquite was the dominant species. All mesquite individuals were registered, measuring their height, crown projection, and wood volume. The canopy density, frequency, and importance value (IV) were determined, as well as basal diameter (BD), length of the main stem and in branches with diameters greater than 5 cm, the inferior and superior diameter and corresponding length. The physiognomy of the studied sites was dominated by shrub and arboreal plants, where the most outstanding vegetation was Prosopis glandulosa. The total floral diversity found were 160 taxa belonging to 59 families, of which Poaceae, Asteraceae, Cactaceae, Fabaceae, and Euphorbiaceae presented the greater number of taxa. The average density of shrubs was of 6575 individuals/ha. The accumulated average cover per site taking in consideration the three layers was 203.20%, being the shrub layer the greatest vegetative cover (85.6%). The shrub and arboreal layers presented greatest IVs (80.31%) of P. glandulosa. The timber volume was significantly greater in arboreal layers (64.675 m3/ha) than shrub layers (26.563 m3/ha). The wood volume had a strong relationship with the variables of BD and crown projection. The relative values of vegetative cover, frequency, density, and IV of P. glandulosa varied significantly by site. In the arboreal layer, P. glandulosa reached the greater percentage in all the parameters, dominating completely the stratum. In most of the sites, the mesquite population was integrated by young individuals with short vegetative development, BDs smaller than 20 cm, height average of 4.86 m, cover average of 23.03 m2, and total density of 554.87 individuals/ha in the shrub and arboreal layers.