Symposium 8 (PT 1). 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
Methodological advances in the latest years have opened new perspectives for dendrochonological studies by facilitating the visualization, delimitation, and analyses of tree-rings. These novel methodologies have incorporated complementary physical and chemical parameters to the traditional anatomical procedures used to describe annual growth rings. Here, we present the results of new studies which explore the relationships among wood density features and chemical elements involved in the a...
Exploring new study sites and potential species is still a fundamental step in tropical dendrochronology. The results of exploratory field campaigns usually reflect the intrinsic biodiversity of the tropics: a plethora of wood anatomy variation and seemly true tree-ring boundaries. Often, some species are excluded during the process of selecting the best species due to indistinct or rather unclear tree-ring delimitation, aside from the difficult task to discriminate the commonly found fals...
Tropical regions are generally characterized by dynamic ecosystems where the abundant availability of energy and resources allows for an almost constant growth of its flora, being xeric forests and flood plains some exceptions. Classical dendrochronology studies have been scarce in these areas as many tree species does not show well defined tree-ring boundaries. We present different study cases on how quantitative wood analysis and radiocarbon can complement classical dendrochronology incr...
In tropical environments of central America, tree-ring forming species are rare to find, especially in areas with pronounced aseasonality, but wood anatomical traits can equally provide important information on species life-histories and response to disturbances. Dating wood anatomical structures remains a crucial task to decipher the ecological information recorded in xylem cellular parameters in absence of defined ring boundaries, particularly to observe the footprint of discrete disturb...
The state of fragmented populations of tree Polylepis genus heavily impact by human activities leads to the need to conduct ecological studies to better understand their vulnerability. We evaluated the newly identified tree species Polylepis rodolfo-vasquezii, endemic to central Peruvian Andes, distributed from 3700 to 4750 m a.s.l. and suitable for dendrochronological studies. Our objectives were twofold: (1) to determinate age population in both forests and developed linear models that c...
In the tropical Andes several species of the genus Polylepis have been reported to be useful to record climate variability using tree-ring width, expanding the geographical distribution of proxy records into the tropical region. However, in the tropics classical dendrochronology based on ring-width patterns is often challenging, hampering the development of climate reconstructions. Alternative methods can confirm annual periodicity of tree rings, and help on extracting more reliable climat...
Given the short span of instrumental hydroclimatic records in the South American Altiplano, longer time records are needed to understand the nature of climate variability and to improve the predictability of precipitation, a key factor modulating the socio-economic development in the Altiplano and adjacent arid lowlands. In this region growths P. tarapacana, a long-lived tree species being very sensitive to hydroclimatic changes and widely used for tree-ring studies in central and southern...
Polylepis tarapacana is the longest paleoclimatic tree-ring archive in the South American southern tropics. It grows up to 5200 m a.s.l. in the South American Altiplano, a semiarid-high elevation Andean Plateau. P. tarapacana ring-widths (RW) have provided centuries of past hydroclimate information, but the potential use of tree-ring stable isotopes for paleoclimatic or ecophysiological studies remained understudied for this species. Here, we developed a network of four RW, oxygen (δ18O) a...
