The Potential of Tree Rings for the Study of Forest Succession in Southern Mexico

Studies of tropical secondary forest succession face strong limitations due to the slow pace of succession and the time-consuming task of monitoring processes. The occurrence of tree rings in secondary forest trees may help expand our knowledge on succession in these systems and may be useful for fallow dating in chronosequence studies. We examine here the potential of tree rings to study forest succession by sampling 70 species along chronosequences of dry and wet forests in southern Mexico. Based on wood anatomical features, we estimated that about 37 percent of the species presented distinct growth rings useful for ring studies. Overall, maximum number of rings matched well the interview-based fallow ages but, at some sites, trees had consistently higher numbers of rings, probably due to errors in fallow ages derived from interviews. Best fallow age estimations were obtained by examining rings in both pioneer and nonpioneer species. Reconstruction of species' establishment dates revealed that pioneer and nonpioneer species establish early during succession, and that species of both groups continue to recruit after many years. Our study clearly shows that tree ring analysis is a promising tool for studies on secondary forest succession in the tropics.