Tree-ring formation, radial increment and climate–growth relationship: assessing two potential tree species used in Brazilian Atlantic forest restoration projects

Abstract

This paper provides an overview of radial growth and tree-ring formation of two tropical tree species used in ecological restoration. It shows that trees growing in natural forests and in plantations have the same diametric growth patterns and climate responses. Understanding the outcomes of ecological restoration projects represents an important step in the conservation of endangered biomes such as the Atlantic forest in Brazil. Tree-ring analysis provides long-term information about the growth dynamics of tree species that can be used to evaluate the potential of different species for restoration projects. To evaluate the potential of using Pseudobombax grandiflorum (Cav.) A. Robyns and Citharexylum myrianthum Cham. in restoration projects in the endangered Atlantic Rain Forest (Reserva Biologica de Poco das Antas—RBPA, Rio de Janeiro, Brazil), we verified the seasonality of tree-ring formation to analyze radial growth dynamics and climate–growth relationships of these species. Cambium wounding experiments and direct anatomical analysis of the cambial zone were conducted to assess tree-ring formation periodicity. Tree-ring widths were measured to build tree-ring chronologies and to estimate radial growth rates in natural and planted areas. Both species produced annual tree rings that are produced during the wet season. Tree-ring chronologies of both species have a positive association with rainfall, but each species also responded to rainfall of a specific season. Tree-ring widths of P. grandiflorum were correlated with rainfall at the end of the previous growth season while tree-ring widths of C. myrianthum were correlated with precipitation in the beginning of the growth season. Both species have fast radial growth, but different long-term growth trends. The growth trend for Pseudobombax grandiflorum produces a positive correlation between diameter and age for the trees, while trees of Citharexylum myrianthum have an age-related growth trend and grow faster in the early years. In the present study, we confirm the success of the ecological restoration performed in RBPA as the plantation does not affect the potential growth of the studied species.