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Native trees and shrubs that grow in the semiarid regions of northeastern Mexico are important feed resources for range ruminants and white-tiled deer. They also provide high quality fuelwood and timber for fencing and construction. Since water stress is the most limiting factor in this region, the present work was focused to study how seasonal leaf water potentials ( ) of native tree species are related to soil water availability and evaporative demand components. Studied tree species were: Cordia boissieri (Boraginaceae), Condalia hookeri (Rhamnaceae) Diospyros texana (Ebenaceae) and Bumelia celastrina (Sapotaceae). Determinations of in the four native tree species were at 10 days intervals between July 10 and November 30, 2007 by using a Scholander pressure bomb. was monitored in five different plants per species at 06:00 h ( p, predawn) and 14:00 h ( md, midday). Air temperature, relative humidity, vapor pressure deficit, precipitation and soil water content were registered throughout. data were subjected to one-way ANOVA and correlation analysis. During the wettest period (Sep-10) p ranged from-0.72 (C. boissieri) to-1.30 MPa (B. celastrina), in contrast, during the driest period (Nov-30), m varied from-2.90 (B. celastrina) to-6.10 MPa (D. texana). Diurnal values were negatively correlated with air temperature and vapor pressure deficit, in contrast, a positive relationship was found with relative humidity. The ability of tree species to cope with drought stress depends on the pattern of water uptake and the extent to control water loss through the transpirational flux