No Evidence that the Valuable Timber Species, Dalbergia retusa, Enhances Nutrient Cycling and Uptake by Neighboring Timber Species

ABSTRACT The use of native species for timber plantations in the tropics has lately gained interest. Recent studies have shown that native tree plantations can have greater economic, and ecological benefits than non-native plantations. Facilitative nutritional interactions with nitrogen-fixing trees are a common practice used in hopes of enhancing nitrogen input. Dalbergia retusa and Terminalia amazonia are two neotropical species frequently used for timber extraction. In order to understand these species belowground interactions, we worked on 33 plots of the T. amazonia and D. retusa mixtures in the Agua Salud Project Native Species plantations in Panama. The objective of this study was to assess if soil biochemical properties under T. amazonia trees might be influenced by D. retusa in these mixtures. For this, soil samples were collected and analyzed for nitrogen pools, extractable cations and selected phosphorus constituents. Our results showed that nutrient concentrations were not significantly different below D. restusa and T. amazonia trees. Nonetheless, temporal and physicochemical characteristics of the plantation might be influencing the tree performance and should be considered for a better understanding of the nutrient dynamics in native tree plantations.