气候变化领域集成服务门户

Trees can adjust their hydraulic architecture by adjusting vessel size and frequency in response to stressful environmental condition. Little is known about the long term adjustment of tropical moist forest trees to changing environment. Here we develop the standard chronologies of seven vessel features and radial growth of two ecologically contrasting South Asian moist forest trees, Toona ciliata M. Roem. and Lagerstroemia speciosa (L.) Pers. and evaluate their hydraulic response to short term climate variability and long term climate variations. Measurements of vessel variables were performed on digital microscopic images. Standard dendrochronological procedure were applied to develop vessel and ring-width chronologies. Relationships among the chronologies and their interaction with climate variables were assessed by Principal Component Analysis (PCA), bootstrap correlations and moving correlations. Pre-monsoon temperature negatively influenced ring-width (RW) and positively influenced vessel density (VD) in T. ciliata. Mean vessel area (MVA) was negatively related with prior year monsoon temperature. In L. speciosa, previous year temperatures and precipitation showed strong correlations with vessel features and radial growth in the following growing season, probably due to carbon carry over effects. Current year October precipitation was positively related with MVA in both species. Differences in functional traits might have caused the observed variation in hydraulic strategies between the two study species. Our analyses suggest that cellular dendrochronology can be used to understand the long-term hydraulic responses of functionally different moist forest trees to climatic changes which is relevant for forest management under changing climate conditions.