Dynamics of non-structural carbohydrates in tropical trees and wood functional traits
Trees use nonstructural carbon (NSC) to run their metabolism. They absorb carbon through photosynthesis and store it as NSC. Storage of nonstructural carbon (NSC) in different organs buffer metabolic demands when photosynthesis is limited, which helps trees to cope with these stressful conditions. These conditions are recurrent throughout trees lifetime and they can reduce photosynthesis. These stressful conditions are increasing with climate change, which impose risks of widespread loss of trees and ecosystem functions around the world. Therefore, it is essential to understand how the storage of NSC in trees contributes to trees' survival to stressful conditions. Nevertheless, for tropical trees it is unknown how they would respond to an increase in stressful conditions and how storage of NSC would contribute to tree survival and resilience. For instance, NSC storage capacity and its spatial distribution in wood may be related with the accessibility and cycling of this carbon reserves, they may impact the time that carbon resides in trees and they may vary between tropical trees with different functional traits. To test this assumption, here we wanted to evaluate the storage capacity, and the spatial and temporal distribution of NSC in tropical trees from a seasonally dry forest in the Amazon in relation to their wood anatomical traits, leaf habit (evergreen and semi deciduous) and life history traits (growth and mortality rates). This dissertation addresses the following question: what are the principal factors that influence the dynamics of allocation and use of NSC storage in the stem wood of some tropical tree species, and how to model these NSC dynamics in order to predict NSC ages and transit times under stressful conditions. These questions were addressed within the three main chapters of this thesis, which are described below.
