Local and Regional Environmental Variation Influences the Growth of Tropical Trees in Selection Trials in the Republic of Panama

background

This study evaluates the effect of varying site conditions on the basal area of 21 neotropical and 2 exotic tree species at three different sites in Panama. 

Research Goals & Methods

Seedlings were planted in 2003 in randomized blocks and measured for basal diameter, height, live crown length, and crown diameter each year from 2004 to 2006.

Conclusions & Takeaways

For almost all of the species, basal area was significantly higher at the seasonally wet sites than at the driest site. The authors describe that Acacia mangium (exotic), Ochroma pyramidale, Erythrina fusca, Pachira quinata and Gliricidium sepium had the highest BA at all three sites (with different orders at different sites). The species with the lowest BA were Albizzia adinocephala, Astronium graveolens, Cordia alliodora, Copaifera aromatica, Dipteryx panamensis and Terminalia amazonia. The authors continue to describe responses of the species to within and between site differences in environmental conditions.  Because at the driest site only the nitrogen fixing exotic Acacia mangium demonstrated consistently high growth rates, the authors describe that this exotic species may need to be used as a nurse tree before slower growing native species will establish. However, because A. mangium can be highly invasive on some sites, the authors suggest that it be planted as part of an intimate mixture with O. pyramidale, G. sepium, and possibly P. quinata and Guazuma ulmifolia and harvested early in the plantation after other trees have established.