Early Growth and Survival of 49 Tropical Tree Species across Sites Differing in Soil Fertility and Rainfall in Panama
This research investigates the importance of soil quality upon species survival across a gradient of differing levels of rainfall and dry season length on disturbed land in Panama.
Research Goals & Methods
Four sites were selected representing the four possible combinations of soil fertility and moisture conditions: (1) wet with high fertility soil, (2) wet with low fertility soil, (3) dry with high fertility soil, and (4) dry with low fertility soil. Over a 3 year period, 49 different species (47 native and 2 exotic species) were planted in randomized blocks with the same experimental setup in each site (3 plots per species in every block with 20 saplings planted at 3m x 3m intervals). The growth (height and basal diameter) and mortality of 35,280 trees were measured at one and two years after planting.
Conclusions & Takeaways
Across the 4 sites, 65% of all species did not show significant differences in growth between high- and low-fertility sites or between wet and dry sites. However, in both of the high soil fertility sites, overall height growth and basal diameter were found to be significantly higher across species, and the overall variability in growth was found to be lower, suggesting that differences in growth are more related to differences in soil fertility than to rainfall. In both of the high-fertility sites, 30% of species showed more growth than in the low-fertility sites, compared with 6% of species showing better growth in the wet sites compared to the dry sites. Across-species survival did not clearly relate to either fertility or rainfall, but a relatively higher mortality was observed in the dry site with high fertility soil. The authors emphasize the importance of selecting species for reforestation based on site-specific information and screening trials which test the performance of potential species under different site conditions.
Early growth and survival of 49 tropical tree species across sites differing in soil fertility and rainfall in Panama. Forest Ecology and Management. 2011;261:1580–1589. doi:10.1016/j.foreco.2010.08.019.
- Center for Tropical Forest Science, Smithsonian Tropical Research Institute, Ancón, Panama
- Yale School of Forestry and Environmental Studies, New Haven, CT, United States
- Department of Biology/Centre for Forest Interdisciplinary Research (CFIR), University of Winnipeg, Winnipeg, MB, Canada