Woody plant regeneration in the semiarid Chaco forest: relationship with biotic and abiotic factors in microsites created by logging

Abstract

Logging activities generate microsites that can be colonized by different woody plant species whose regeneration may be influenced by biotic and abiotic factors. This work describes three microsites created by logging (main roads, skid trails and logging gaps) in two sites with different recovery time (one and two years) in the semi-arid Chaco of Argentina. Woody plant richness and diversity are compared and the relationship of plant density as a function of microsite type, recovery time, soil compaction, canopy cover and herbaceous cover is evaluated. Richness and species composition were similar in all microsites, which were dominated by the same species. Main roads presented more compacted soil, skid trails had denser canopies and logging gaps had soils with larger herbaceous cover. Woody plant density depended on the interaction of the covariates (soil compaction, canopy cover and herbaceous cover) with microsites and recovery time. Road plant density was low and was negatively related with soil compaction and positively related with canopy cover as well as with herbaceous cover, suggesting a positive interaction (facilitation) in microsites that were most affected by logging. The regeneration of the two most valuable timber species was low compared to other species. In the microsites studied, Aspidosperma quebracho-blanco had a similar density and Schinopsis lorentzii a higher density compared to the regeneration found in the surrounding matrix reported in other studies, but this result should be interpreted with caution due to the low constancy (proportion of plot containing a certain taxon). We propose, cautiously, that generated microsites would not be negatively affecting the regeneration of the two most valuable timber species in this environment.