High vapour pressure deficit enhances turgor limitation of stem growth in an Asian tropical rainforest tree.

Tropical forests are experiencing increases in vapour pressure deficit (D), with possible negative impacts on tree growth. Tree-growth reduction due to rising D is commonly attributed to carbon limitation, thus overlooking the potentially important mechanism of D-induced impairment of wood formation due to an increase in turgor limitation. Here we calibrate a mechanistic tree-growth model to simulate turgor limitation of radial stem growth in mature Toona cilitata trees in an Asian tropical forest.

[Intra-annual radial growth of in tropical seasonal rain forest and its response to environmental factors in Xishuangbanna, Southwest China].

We examined the seasonal growth dynamics of a deciduous tree species in the tropical seasonal rain forest in Xishuangbanna and monitored the stem radial growth with both high resolution dendrometer and microcoring methods. Combining with the monitoring of non-structural carbohydrates (NSCs) in stem and environmental factors, we analyzed the eco-physiological drivers underlying the seasonal cambial activity and radial growth dynamics. The results of high reso-lution dendrometer method showed that the growth of began at the end of May (day of year, DOY: 149.