Decomposition of greenfall vs. senescent foliage in a tropical forest ecosystem in Puerto Rico

In many forest ecosystems, green leaf deposition (greenfall) constitutes an enrichment over background levels of litterfall nutrients and may therefore influence key ecosystem processes. This study examined the litter quality and decomposition rates of green leaves compared to senescent litterfall for four dominant tree species (Dacryodes excelsa, Manilkara bidentata, Guarea guidonia, and Cecropia schreberiana) in a lower montane rain forest at El Verde Field Station, Luquillo Experimental Forest, Puerto Rico. Green leaves from the canopy and freshly senesced leaves from the forest floor were analyzed for carbon, nitrogen, and fiber and placed in litterbags in the field for up to 16 weeks. Green leaves displayed significantly higher rates of decomposition than did senescent litter among all four species. Green leaves also had significantly higher nitrogen concentrations and lower lignin to nitrogen ratios compared to senescent leaves. These results suggest that greenfall may have a major influence on decay processes and nutrient cycling in forests that experience large-scale green foliage removal.