A research team from the South China Botanical Garden of the Chinese Academy of Sciences (CAS) studied the global variability of plant hydraulics in relation to wind speed. Their findings were published in Nature Ecology & Evolution.
Wind has long been recognized as an important ecological factor affecting forests. Its impact on plant hydraulics is multifaceted, involving elements related to water and energy balance and interactions with plant morphology. Despite these insights, the global effect of wind on plant hydraulics remains poorly understood.
In this study, the researchers utilized field measurements, a plant traits database, and published literature to establish a comprehensive global dataset on plant hydraulics. This dataset encompasses key parameters such as water potential at 50% loss of hydraulic conductivity (P50), xylem-specific hydraulic conductivity (Ks), leaf area to sapwood area ratio (AL/AS), and conduit diameter (D). The dataset spans 1,922 woody species sampled from 469 locations worldwide, representing 2,786 species-at-site combinations.
The researchers discovered that wind speed influences plant hydraulics, even when controlling for other climatic factors such as moisture index, temperature, and vapor pressure deficit. Species that grow in windier environments tend to develop sapwood with smaller conduit diameters and lower xylem-specific hydraulic conductivity. These traits improve drought resilience by reducing water loss, as plants with smaller leaf areas relative to sapwood cross-sections require less water to maintain their physiological processes.
"Species with these traits may have an advantage in future climates characterized by higher wind speeds," said Dr. HE Pengcheng, the first author of the study. "Given the rapid increase in wind speeds observed over recent decades, it is crucial to recognize that the effects of wind on plants-such as shaping hydraulic traits to enhance drought tolerance-might partially counterbalance the impacts of other global changes, including CO2 fertilization, nitrogen deposition, and global warming."
Furthermore, the study highlights the potential to enhance global vegetation models by incorporating mechanistic links between wind speed and plant hydraulics, which could improve predictions of ecosystem responses to changing climatic conditions.
This study offers a global perspective on the significant effects of wind on plant hydraulic traits; however, the mechanisms behind these findings are not yet fully understood.
Figure 1. Conceptual framework for water fluxes in plants under different wind scenarios. High wind speeds reduce canopy and vegetation boundary layer resistances, leading to increased atmospheric aridity and mechanical damage to plants. Under this condition, it is advantageous for plants to have high drought tolerance, low leaf area on branches, and high mechanical resistance. By contrast, in areas with low wind speeds, plants benefit from high water transport and fast growth because low wind speeds result in less drought stress, defoliation, and windthrow.(Image by HE et al)
