Seedling survival and growth of native tree species in pastures: Implications for dry tropical forest rehabilitation in central Panama

Abstract

Our study tested the effects of herbicide application and cattle removal on the survival and growth of three native tree species planted in pastures within a deforested, dry tropical region of Panama. We investigated whether enrichment planting may be a potential, complementing reforestation tool with natural regeneration. Three economically valuable tree species were chosen for the study; Cedrela odorata L., Enterolobium cyclocarpum (Jacq.) Griseb, and Copaifera aromatica Dwyer. Planted seedlings were monitored for survival, root collar diameter and height growth in the presence or absence of two factors; (1) initial herbicide application and (2) cattle. After 16 months, subsamples of seedlings within each treatment were harvested and measured for dry masses and leaf areas. In the initial stages of development, C. odorata seedlings had the greatest growth rates with herbicide application whereas E. cyclocarpum seedlings had the greatest growth rates with cattle exclusion. The combination of these two factors yielded the best growth for both species. Of the three species, C. odorata had the lowest mortality rates (58%), and the greatest average dry mass ( μ = 403.7 g), leaf area ( μ = 169.3 m 2), diameter growth rate ( μ = 3.7 cm year −1) and height growth rate ( μ = 81.7 cm year −1) at 16 months. In addition, in the presence of cattle, C. odorata grew significantly better than E. cyclocarpum. To accelerate forest succession, herbicide should be applied initially and cattle removed before enrichment planting.