LAUSR

The present study was undertaken to determine interspecific variations of carbon and nitrogen contents of 37 species of woody trees sand shrubs at Linares, Northeastern Mexico. Woods were collected, dried and powdered following standard procedure. Ashed sample was digested in a solution containing HCl and HNO3, using the wet digestion technique. Wood carbon and nitrogen contents (%, dry mass basis) were carried out on 0.020 g of milled dried leaf tissue by using a CHN analyser (Perkin Elemer, model 2400). Wood carbon showed large variations among species (37-51 %) and nitrogen content (0.56-1.97). The five species selected with very high carbon percentage are such as Bernardia myricifolia (51.12); Acacia berlandieri (51.00); Leucophyllum frutescens (50.84); Berberis chochoco (50.56); Havardia pallens (50.36). Similarly, the species showed variations in nitrogen content (0.56-1.97). The species containing high wood nitrogen are Acacia greggii (1.98%), Ebenopsis ebano (1.97 %), Sideroxylon celestrinum (1.75 %), Diospyros texana (1.56 %), and Guaiacum angustifolia (1.52 %). The species with high wood carbon are potential sources of bioenergy and carbon sink. These species store high amounts of carbon following carbon fixation by leaves.