Temperature and rainfall strongly drive temporal growth variation in Asian tropical forest trees

Abstract

Climate change effects on growth rates of tropical trees may lead to alterations in carbon cycling of carbon-rich tropical forests. However, climate sensitivity of broad-leaved lowland tropical trees is poorly understood. Dendrochronology (tree-ring analysis) provides a powerful tool to study the relationship between tropical tree growth and annual climate variability. We aimed to establish climate-growth relationships for five annual-ring forming tree species, using ring-width data from 459 canopy and understory trees from a seasonal tropical forest in western Thailand. Based on 183/459 trees, chronologies with total lengths between 29 and 62 years were produced for four out of five species. Bootstrapped correlation analysis revealed that climate-growth responses were similar among these four species. Growth was significantly negatively correlated with current-year maximum and minimum temperatures, and positively correlated with dry-season precipitation levels. Negative correlations between growth and temperature may be attributed to a positive relationship between temperature and autotrophic respiration rates. The positive relationship between growth and dry-season precipitation levels likely reflects the strong water demand during leaf flush. Mixed-effect models yielded results that were consistent across species: a negative effect of current wet-season maximum temperatures on growth, but also additive positive effects of, for example, prior dry-season maximum temperatures. Our analyses showed that annual growth variability in tropical trees is determined by a combination of both temperature and precipitation variability. With rising temperature, the predominantly negative relationship between temperature and growth may imply decreasing growth rates of tropical trees as a result of global warming.

Tree Age Distributions Reveal Large-Scale Disturbance-Recovery Cycles in Three Tropical Forests

“…For all four Thai species the annual nature of the rings was also proven by a cambial wounding experiment in HKK (Baker et al, 2005). The annual growth periodicity was further supported by strong correlations between Afzelia, Chukrasia, Melia , and Toona tree-ring chronologies and seasonal climate data (Vlam et al, 2014b). …”

“…Cross-dating within trees was successful, cross-dating among trees proved, however, more difficult (Groenendijk et al, 2015). We were able to construct chronologies for the four Thai species (Vlam et al, 2014b), but not for the Bolivian and Cameroonian species (Groenendijk et al, 2014). We stress that our study was not aimed at, nor designed to, establish chronologies, we included for example many small (juvenile) trees which can typically be poorly cross-dated.…”

Growth and reproduction respond differently to climate in three Neotropical tree species

“…Our analyses are also strengthened by the use of local meteorological data, in comparison with other studies using gridded climatic data or data from stations located further from the study sites which may underestimate climate-growth correlations (e.g. Vlam et al 2014). …”

Seasonal variations in the stable oxygen isotope ratio of wood cellulose reveal annual rings of trees in a Central Amazon terra firme forest

“…Our knowledge of forest dynamics in the region, including rates of individual tree growth, mortality, and lifespan, is limited (Chambers et al 2013), in part due to the absence of annual rings as a convenient dating tool. Such information is critical for understanding many processes related to forest dynamics and carbon cycling and for evaluating the impacts of future climate change on tropical ecosystems (e.g., Clark et al 2003;Clark 2007;Brienen et al 2010;Vlam et al 2014).…”