Claudio Sergio Lisi

Tree-Ring Formation, Radial Increment Periodicity, and Phenology of Tree Species from a Seasonal Semi-Deciduous Forest in Southeast Brazil

Many tropical tree species produce growth rings in response to seasonal environmental factors that influence the activity of the vascular cambium. We applied the following methods to analyze the annual nature of treering formation of 24 tree species from a seasonal semi-deciduous forest of southeast Brazil: describing wood anatomy and phenology, counting tree rings after cambium markings, and using permanent dendrometer bands. After 7 years of systematic observations and measurements, we found the following: the trees lost their leaves during the dry season and grew new leaves at the end of the same season; trunk increment dynamics corresponded to seasonal changes in precipitation, with higher increment (active period) during the rainy season (October–April) and lower increment (dormant period) during the dry season (May–September); the number of tree rings formed after injuries to the cambium coincided with the number of years since the extraction of the wood samples. As a result of these observations, it was concluded that most study trees formed one growth ring per year. This suggests that tree species from the seasonal semi-deciduous forests of Brazil have an annual cycle of wood formation. Therefore, these trees have potential for use in future studies of tree age and radial growth rates, as well as to infer ecological and regional climatic conditions. These future studies can provide important information for the management and conservation of these endangered forests.

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

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.

Dendroecological Studies in the Neotropics: History, Status and Future Challenges

We review a vast literature of Neotropical forest science and wood anatomical research that identifies 220 tree species from 46 botanical families with confirmed annual tree-ring formation. External factors that trigger annual growth rhythms include rainfall seasonality, annual long-term flooding (flood-pulse), soil water salinity (mangroves), and, with increasing latitude and altitude, photoperiod and temperature. Maximum ages for tropical angiosperms derived from tree-ring analyses generally do not exceed 400–600 years; however, at marginal sites characterized by extremely limited growth conditions individual trees might get older. Dendroecological applications provide insights into tree species’ ecology and forest dynamics. Analyses of growth trajectories and age-size relationships of trees highlight considerable variability among individual trees, species, and environments. In recent decades tree-ring studies in neotropical forests have contributed new methods to project timber harvests and to evaluate and adjust management practices to increase the sustainability of forest management. The better understanding of individual- and species-level growth patterns in the Neotropics provides necessary empirical information to conserve and manage tropical forests and the many ecosystem functions and services that they maintain.

Anatomia comparada do lenho de Caryocar brasiliense (Caryocaraceae) em fisionomias de cerradão e cerrado sensu stricto

Este trabalho verificou a influencia das condicoes ambientais na estrutura do xilema secundario da especie Caryocar brasiliense Camb. (pequizeiro) atraves de um estudo anatomico comparado do lenho de arvores procedentes de fisionomias de cerradao e cerrado s.s., no municipio de Santa Rita do Passa Quatro, SP. As caracteristicas do lenho foram analisadas qualitativa e quantitativamente, sendo as ultimas comparadas pela analise de variância, bem como por analises multivariadas de agrupamentos e componentes principais. A analise de variância demonstrou existir diferencas significativas para oito das dezesseis variaveis analisadas, bem como uma grande variacao entre arvores da mesma localidade, aspecto corroborado pela analise de agrupamentos. A matriz de correlacao entre variaveis indicou, de modo geral, relacoes inversas entre dimensoes longitudinais e radiais dos elementos anatomicos. Pode-se inferir pela variabilidade significativa entre arvores que a diferenciacao das fisionomias ocorre de forma gradual, nao se observando um conjunto de caracteristicas anatomicas suficientemente marcantes que tipifiquem as fisionomias estudadas.