Removal of Climbing Plants and Soil Plowing as a Strategy to Enhance Forest Recovery in Tropical Dry Forests Old Fields

Restoration practices are still scarce for the dry tropics. In this study, we tested if the removal of climbing plants and soil plowing (assisted natural regeneration) enhanced tree biomass accumulation within tropical dry forest old fields (defined as cattle pastures abandoned for ca.10 years) on the Pacific Coast of Mexico. In each of three old fields, six 25-m2 blocks were randomly positioned. The soil from three blocks was plowed and climbing plants removed from the tree stems and canopy; another three blocks were used as experimental controls. Climber removal was done at the beginning of the experiment and 7, 17, 25, 30 and 37 months later. The soil was plowed twice, once at the beginning of the experiment and again 7 months later. Before and after assisted natural regeneration, all woody stems (i.e., tree species dbh > 1cm) and their canopy cover were recorded to calculate the rate of increase in standing biomass and stem growth and survival. The results showed a strong site effect on the response of trees to assisted natural regeneration. Nevertheless, all sites showed a significantly positive effect of assisted natural regeneration on overall biomass gain despite differences in vegetation structure and tree species composition. Removal of climbing plants and soil plowing concurrently appeared as a useful technique for tropical dry forest recovery. Further studies, however, are needed to evaluate if the initial trends of recovery are maintained over the long term.