Impact of precipitation and temperature on structural and hydraulic
traits of evergreen and deciduous plants: a global synthetic analysis
Abstract
Elevated temperature often coincides with drought events, which is
widely considered as a primary driver of hydraulic failure. Here, we
analyze the associations among climatic factors, woody structural traits
and hydraulic traits based on a data set comprising over 4,000
observations from 1990 to 2023. The structural equation model (SEM)
revealed that both mean annual precipitation (MAP) and mean annual
temperature (MAT) exhibited positive effects on specific hydraulic
conductance (Ks, effects: 0.06 and 0.96) and negative effects on
embolism resistance (-P50, effects: -0.30 and -0.26). Additionally, we
compared structural and hydraulic traits across seven major biomes. The
results indicated that tropical forests exhibited higher Ks and lower
-P50, accompanied by significantly larger conduit diameter (D) and lower
conduit densities (Dens) compared to other biomes. Furthermore, along
the hydraulic efficiency and safety axis, evergreens tended to favor
safety, while deciduous species leaned towards hydraulic efficiency,
with 16.48% evergreen observations occupying a high hydraulic safety
pattern (-P50>5MPa). Moreover, stronger relationships between
the structural traits of evergreen plants and climatic factors were
observed compared to deciduous species. In conclusion, we emphasize that
elevated temperature may hinder structural adaptation to drought,
ultimately leading to hydraulic failure and forest mortality.