Annual tree rings in Piptadenia gonoacantha (Mart.) J.F.Macbr. in a restoration experiment in the Atlantic Forest: potential for dendroecological research

ABSTRACT The tree Piptadenia gonoachantha is widely used in forestry and in forest restoration projects, which require methods for evaluating tree growth. Long-term studies are necessary to determine patterns and detect changes in species growth rhythms. Tree ring analysis provides a precise method for determining age and documenting long-term growth trends in tropical tree species. The present study evaluated the periodicity of tree ring formation and radial growth dynamics of P. gonoachantha from a population of known age in the Poço das Antas Biological Reserve. Two radii from six trees were sampled using non-destructive methods. Tree rings were counted and measured to estimate age and to calculate diametric increment. All samples had 16 tree rings, which matched the known plantation age and confirmed the annual formation of rings. The individuals sampled had a mean annual diametric increment of 9.5 mm / year. Results showed a trend towards decreasing growth rate with increasing age. Individuals of P. gonoachantha in Ombrophilous Dense Forest produce annual tree rings, which holds potential for future dendroecological studies

Diversity of growth responses to recent droughts reveals the capacity of Atlantic Forest trees to cope well with current climatic variability

Understanding the behavior of trees and how they will respond to future climate change is a crucial conservation challenge, especially for tropical species. Despite the high diversity of tree species in Brazil, little is known about their tolerance limits. The study of tree rings is a valuable method for the analysis of growth dynamics with superposed epoch analysis being a good way to understand whether past dry years induce decreased tree growth, how long it takes to recover growth after a dry period, and the resilience of trees. This study investigated seven legume species (deciduous and evergreen) from three different sites in the Atlantic Forest in the state of Rio de Janeiro, Brazil. The studied trees seem to have coped well with the drought periods experienced thus far with no common pattern of recovery among species at the same site. The trees were not affected in a similar way and so different mechanisms are likely involved in preventing significant decreases in growth. These data are important for conservation policies because they reveal that each species requires a unique analysis.We thank the Laboratorio de Botanica Estrutural from Instituto de Pesquisas Jardim Botanico do Rio de Janeiro and the CNPq (Conselho Nacional de Desenvolvimento Científico Tecnologico) for the PDJ and Pesquisador Visitante fellowships, as well as CAPES (Coordenaçao de Aperfeiçoamento de Pessoal de Nível Superior), PPBIO (Programa de Pesquisa em Biodiversidade), and FAPERJ (Fundaçao Carlos Chagas Filho de Amparo `a Pesquisa do Estado do Rio de Janeiro) for the research fellowship grant

Fire records in tree rings of Moquiniastrum polymorphum: potential for reconstructing fire history in the Brazilian Atlantic Forest

ABSTRACT Fire disturbance affects the composition, structure and dynamics of vegetation. Historical records of fire events exist in some places, but they are generally limited in temporal and spatial extent. Tree-ring research is a useful tool for fire history reconstruction and can contribute important long-term ecological data. We tested the hypotheses that Moquiniastrum polymorphum (Less.) G. Sancho, a widespread species in Brazil that occurs in burnt areas of Atlantic Forest, produces annual growth rings and that its wood can record fire incidence by datable fire scaring. Our results corroborate these hypotheses and indicate that the species has potential for fire history reconstruction