With the intensification of global warming and the frequent occurrence of extreme drought events, analyzing the seasonal dynamics of tree growth and xylem anatomical characteristics is crucial for predicting the resilience of forest ecosystems. However, research on the intra-annual stem growth and xylem formation of dominant trees in subtropical humid forests remains limited.
In a study published in Tree Physiology, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences investigated the inter-annual stem growth and cell formation of two dominant canopy species of a subtropical evergreen broad-leaved forest in Southwest China, as well as their responses to seasonal climate variability.
The researchers investigated intra-annual stem growth and xylem formation in two diffuse-porous tree species, Stewartia pteropetiolata and Schima noronhae, which are dominant and coexist in the subtropical evergreen forest in the Ailao Mountain in Southwest China .
Using high-precision tree growth instruments, the researchers continuously monitored changes in tree stem radius. Combining with micro-core paraffin sectioning technology, they quantified the expansion, thickening, and maturation processes of vessels and fiber cells during xylem development. They also employed a generalized linear model to analyze the main environmental drivers of tree radial growth and xylem development.
The researchers observed distinct seasonal patterns of stem growth and cell formation in both species, likely linked to their wood anatomical features and stress tolerance. Both species maintained high relative growth rates under warm temperatures and low atmospheric dryness (vapor pressure deficit). However, S. noronhae thrived only within a limited range of favorable rainy-season conditions, while S. pteropetiolata exhibited remarkable endurance across a broader span of colder, drier periods.
The study underscores how wood anatomy—vessel size, cell-wall thickness, and growth phase timing—dictates tree species’ ecological niches and climate resilience. These traits likely explain their distinct distributions across elevation gradients in subtropical forests.
Contact
FAN Zexin Ph.D Principal Investigator
Xishuangbanna Tropical Botanical Garden
E-mail: fanzexin@xtbg.org.cn
Published: 17 February 2025
