ABSTRACT:Restoration of native vegetation and fuelwood production are important environmental pending goals for Mexico, where years of wrong management practices resulted in ecosystemic degradation and fuelwood scarcity. In degraded areas, native rhizobial strains are often undetectable, therefore, the restoration of natural vegetation associated with an effective nodulation of the leguminous trees is mostly appropriate. Sinorhizobium americanum is a native nitrogen-fi xing bacteria isolated from nodules of the native Acacia species in the region. Acacia farnesiana is a multipurpose leguminous shrub from Mexican seasonally dry tropical forests (SDTF). In this study we analyzed the effect of inoculation with S. americanum on A. farnesiana growth in a greenhouse and in a very degraded area and compared with non-inoculated seedlings. In a greenhouse, we measured the biomass dry weight of different parts of the plant, using destructive sampling after 15, 20, 30, 45 and 120 days of growth. We also calculated the relative growth rate (RGR) and the resources allocation (root/shoot weight ratio and root length/root dry weight) of seedlings. In a degraded area we measured the seedling length and survival and calculated the RGR. In the greenhouse and in the degraded area, the inoculation positively affected the growth of seedlings. However in the greenhouse, the inoculation did not have effect on resource allocation patterns. Therefore, the inoculation with Sinorhizobium americanum could improve the A. farnesiana growth and the re-establishment of important plant-soil interactions in degraded areas, being a recommendable technique for land restoration and the improvement of fuelwood production. RESUMO: Restauração da vegetação nativa e produção de lenha são importantes metas ambientais pendentes para o México, onde anos de práticas de manejo equivocadas provocaram degradação ecossistêmica e escassez de lenha. Nessas áreas degradadas, estirpes de rizóbio nativas são muitas vezes indetectáveis e, portanto, a restauração da vegetação natural, associada com uma nodulação efetiva das árvores leguminosas é mais adequada. Sinorhizobium americanum é uma bactéria fi xadora de nitrogênio isolada de nódulos de espécies nativas de Acácias na região do experimento de campo. Acacia farnesiana é um arbusto leguminoso com múltiplos usos, nativo das fl orestas tropicais estacionalmente secas do