Patterns of tree growth in relation to environmental variability in the tropical dry deciduous forest at Mudumalai, southern India

Abstract

Tree diameter growth is sensitive to environmental fluctuations and tropical dry forests experience high seasonal and inter-annual environmental variation. Tree growth rates in a large permanent plot at Mudumalai, southern India, were examined for the influences of rainfall and three intrinsic factors (size, species and growth form) during three 4-year intervals over the period 1988-2000.Most trees had lowest growth during the second interval when rainfall was lowest, and skewness and kurtosis of growth distributions were reduced during this interval. Tree diameter generally explained <10% of growth variation and had less influence on growth than species identity or time interval. Intraspecific variation was high, yet species identity accounted for up to 16% of growth variation in the community. There were no consistent differences between canopy and understory tree growth rates; however, a few subgroups of species may potentially represent canopy and understory growth guilds. Environmentally-induced temporal variations in growth generally did not reduce the odds of subsequent survival.Growth rates appear to be strongly influenced by species identity and environmental variability in the Mudumalai dry forest. Understanding and predicting vegetation dynamics in the dry tropics thus also requires information on temporal variability in local climate.

Asynchronism in leaf and wood production in tropical forests: a study combining satellite and ground-based measurements

“…The seasonality of wood production was consistent with observations from other tropical forests, even those tropical forests without any month with precipitation below 100 mm (Clark et al, 2010;Grogan and Schulze, 2012;Wagner et al, 2012;Nepstad et al, 2002). This intra-annual seasonality cannot be considered as the sole result of bark shrinkage and swelling (Fig.…”

“…The phenological consequences of long-term changes in solar radiation or alterations in diffuse/direct components still remain an open question in tropical forests (Lewis et al, 2004). However, we know that the frequency of drought events should increase (Solomon et al, 2007(Solomon et al, , 2009, and as a consequence cloudiness should decrease while irradiance should increase (Nemani et al, 2003;Arias et al, 2011). Further analysis is needed to understand the link between leaf dynamics and climate in order to decipher whether the trigger of leaf fall is the peak of irradiance, an intrinsic biological clock, another climate driver sensitive to climate change, or all these factors combined.…”

“…wood production, in tropical forests have been highlighted in most longterm permanent plots (Nepstad et al, 2002;Stahl et al, 2010;Wagner et al, 2012), even under very stable climate conditions (O'Brien et al, 2008;Clark et al, 2010). This seasonality is obviously linked to the intra-annual variation of cambial activity that has been reported in various environments, from dry (Worbes, 1999;Enquist and Leffler, 2001;Lisi et al, 2008) to flooded forests (Schongart et al, 2002), but also in more mesic environmental conditions (Fichtler et al, 2003;Clark et al, 2010).…”

“…Field measurements of productivity, reported as biomass gain or growth in diameter at breast height (DBH), showed an increase in the wet season (Wagner et al, 2012;Grogan and Schulze, 2012;Nepstad et al, 2002;Clark et al, 2010); satellite measurements of productivity, reported in terms of increasing canopy photosynthetic capacity, were correlated with leaf production and peaked in the dry season (Huete et al, 2006;Brando et al, 2010;Anderson, 2012). In this study, we use a unique combination of three independent data sets to resolve this apparent absence of synchronism in leaf and wood production in tropical forests.…”

Crescimento em diâmetro do Pinus elliottii e Pinus taeda em áreas arenizadas e degradadas no Oeste do Rio Grande do Sul

“…O crescimento das árvores em geral aumenta com a precipitação (MURPHY & LUGO, 1986) e diminui com a seca (NATH et al, 2006), mas, independentemente da chuva, a fertilidade do solo pode afetar a taxa de crescimento das árvores (LU et al, 2002;MALHI et al, 2004), obtendo-se um maior crescimento em solos mais ricos em nutrientes (RUSSO et al, 2005). Por outro lado, a disponibilidade de água da área depende da posição topográfi ca em que ela se encontra, pois infl uencia diretamente o desenvolvimento das plantas do local, assim como a formação do solo (HANNAH et al, 1982).…”