Initial performance and reforestation potential of 24 tropical tree species planted across a precipitation gradient in the Republic of Panama

Decades of deforestation and unsustainable land use have created large expanses of degraded lands across Central America. Reforestation may offer one means of mitigating these processes of degradation while sustaining resident human communities. However, a lack of information regarding tree species performance has been identified as an important limitation on the success and adoption of diversified reforestation strategies. We analyzed the initial growth of 22 native and 2 exotic tree species planted at three sites across a precipitation gradient in the Republic of Panama (1100-2200 mm year(-1)), and identify promising species for use in forest restoration, timber production and on-farm systems. At all sites, Acacia mangium, Diphysa robinoides, Gliricidia sepium, Guazuma ulmifolia and Ochroma 1,pyramidale rapidly developed large, dense crowns and attained canopy closure after just 2 years. These species might be used in restoration efforts to rapidly stabilize soils and establish crown cover. As nitrogen-fixing legumes, D. robinoides and G. sepium may also have the potential to increase soil fertility. Several species valued for their timber performed well at all sites attaining high wood volume indices, these species included Tectona grandis, Pachira quinata and Tabebuia rosea. Albizia guachapele and Samanea saman were among the best performers at the driest site. The most promising species for use in silvopastoral systems varied among sites; A. guachapele, G. sepium, S. saman and G. ulmifolia performed best at the driest site, while G. sepium, G. ulmifolia and Spondias mombin were the top performers at the two wetter sites. It is hoped that the results of this trial will improve the success of reforestation efforts by allowing landholders to select species based upon both local site conditions and their specific reforestation objectives. (c) 2007 Elsevier B.V. All rights reserved.