Dendrochronology of lianas of the Leguminosae family from the Atlantic Forest, Brazil

Abstract

Information about plant growth, development and age forms the basis for understanding complex forest ecological processes. Although lianas play an important role in tropical forests, little is known about their growth and development from either climatic or ecological perspectives. Therefore, we studied the growth rings in Legume liana species collected in a mountainous Atlantic Forest in southeastern Brazil. Four of the eight studied species did not show cambial variants, three had a lobed stem, and one had a furrowed xylem. Distinct growth rings were observed in all species. Semi-ring porosity, marginal parenchyma, fibrous zone and radially flattened latewood cells were the main characteristic features of these growth rings. Species without cambial variants, including Dalbergia frutescens, Piptadenia adiantoides, P. micracantha and Senegalia tenuifolia, showed very distinct growth rings visible in macroscopic and microscopic analysis. Ring-width time series and cambial wound assessment were performed to analyze periodicity and dendrochronology. The species with cambial variants, S. grandistipula, S. lacerans, S. martiusiana and S. pedicellata, also showed distinct growth rings, however, sometimes barely detectable or not detected at all. Cambial wounding, cross-dating and climate-growth relationships indicated the annual nature of growth rings in species without cambial variant. Cross-dating between radii within one individual and between individuals was successful, and the synchronized series enabled us to build species chronologies and a mean chronology. Climate-growth analysis revealed significant correlations between chronologies and precipitation, indicating that available moisture is the main factor determining growth rates of lianas in the Atlantic forest.