Symposium 8 (PT 2). Dendrochronological progress in tropical Americas
My Session Status
Dendrochronological archives in the tropics of the Americas have been under-studied for a long time. Some of the challenges include the Identification of tree-ring boundaries in certain tree species, absence of winter dormancy associated to low temperatures in most of the cases, and logistic difficulties of fieldwork in remote sites. However, part of the slow progress is also related to the fact that historically much less resources have been invested in dendrochronological research in the tropics than in other regions of the world. Nevertheless, more studies have been published over the last decade leading to important achievements such as the expansion of tree-ring networks due to an increase in the number of available chronologies from a wide variety of tree species, as well as different methodological approaches. In addition to tree-ring width (TRW), now stable carbon and oxygen isotopes, Quantitative Wood Anatomy, autofluorescence and chemistry provide means to develop tree-ring research in the tropical region. In this symposium, we will show progress done in the Tropical Americas highlighting studies from different countries. Mexico has been pioneering with the development of over 40 TRW chronologies, while new TRW chronologies in Guatemala can contribute to a better management of water resources. In South America tree-ring chronologies were generated from multiple tree species measuring distinct parameters at the western (dry) and eastern (wet) flanks in Central Andes of Peru and Bolivia, while in the seasonally dry forests of Brazil, alive and subfossil tree-ring records have been developed. This symposium intends to provide new insights into forest responses to climate, stand dynamics or other environmental events, based on tree-ring analyses, and updated on more useful methodologies with the main goal being to push tropical dendrochronology for the following decades through international collaborative research.
Sub Sessions
The occurrence of annual growth rings in tropical trees—the result of the seasonal activity of vascular cambium—has been explained either by seasonal periods of water deficit or flooding. However, little is known about the drivers of annual tree-ring formation under tropical hyper-humid conditions without evident seasonal dry periods or flooding (ever-wet conditions). Shelford's law states that both the deficit and the excess of environmental resources limit plant growth. Accordingly, we h...
The most biodiverse region in the world can be found in the tropical Andes (~5º-24ºS) between Venezuela and the Bolivian Altiplano, yet it is highly under-sampled in dendrochronology in part due to the prevalence of trees without rings (continuous growth) and the overall hyperdiversity of the ecosystems. The Madidi National Park (MNP) in northern Bolivia. (~14 ºS, -68°W) is a biodiversity hotspot with lowland rainforests and high montane environments that provide unique opportunities for t...
Araucaria angustifolia is an endangered species that occurs in the high and cold regions of southern Brazil. This species has economic importance due to its wood and seeds, as well as playing a fundamental ecological role for the southern fauna and flora. Climate change can affect it sdistributional area and conservation, making it urgent to investigate the effect of climate on its development. The objective of our study was to investigate how growth rates of A. angustifolia vary in relati...
The semi-arid Chaco is one of the most extensive forest formations in South America and has been subjected to high deforestation rates since the 1970s. At present, the main ecological, social and production problem in the region is the variation in water availability, a complex situation that combines a negative water balance and flood events. In this work, we studied the spatial and temporal variability of precipitation patterns, using rainfall instrumental records and tree rings of Schin...
The Caribbean, like much of the tropics, is underrepresented by tree-ring chronologies making global climate reconstructions a challenge because of these blind spots. We have developed a multi-centennial tree-ring chronology from 120 samples of Pinus occidentalis trees located above 2800 m elevation on the dry slopes of Loma la Pelona in the Cordillera Central (19.035278 N, -71.005278 W) of the Dominican Republic. We used skeleton plotting on multiple radii from each crossection to date th...
In this presentation we discuss the current status of tree-ring research in the neotropical Americas outside of México. The most relevant findings are discussed, including the region-wide wet season precipitation signal associated with large-scale tropical atmospheric dynamics. Our analysis suggests that local climate response patterns vary between sites, with the strongest correlations ranging from the previous summer to the current spring. Correlations with accumulation of daily precipit...