A model-based evaluation of plant performance in secondary tropical forest

The management and restoration of secondary forestlands is crucial for economic, social and ecological reasons. To ensure the chances of success of natural regeneration, enrichment planting and plantation programs, the knowledge of plant performance and light requirements and use is crucial. In spite of the importance of matching the light requirements of trees and the light environment in which they were planted to date little work has been done to accurately relate the performance of planted trees to their light climate. A model to evaluate quantitatively light received by trees and carbon gain was developed to relate species-specific traits to whole-plant carbon gain. In addition to light the model considers nitrogen-use by trees and links this to carbon gain. Values for the variables are obtained using destructive sampling of trees or extrapolating data from non-destructive measurements. Several methods are considered to calculate the leaf area of the vegetation which allows estimating the light availability in the canopy. The photosynthetic characteristics can be described accurately based on Nitrogen (N) distribution and species-specific photosynthesis-N relationships. Through this, total carbon gain can be calculated. The model can be used to estimate the growth potential of a given species targeted for enrichment planting. It can also be used to plan silvicultural practices to enhance light acquisition and carbon gains in target species. In this way it can help to bypass the costly and time consuming experiments that would otherwise have to be done to determine the success of a given planting scheme.