Xylem hydraulics and non-structural carbohydrate contents in 15 temperate tree species

In humid temperate forests, the occurrence of frequent freeze-thaw cycles (FTC) is a main factor limiting tree growth, as xylem embolism induced by FTC poses a serious threat to the hydraulic integrity of trees. A high resilience to hydraulic dysfunction involves the enhancement of embolism resistance and/or extra non-structural carbohydrate (NSC) inputs for restoration of an impaired hydraulic system. However, potentially negative implications of such NSC allocation on tree growth have not yet been explored.

At a temperate forest site of northeast China, we studied xylem hydraulics and NSC contents in relation to winter embolism resilience in 15 sympatric broadleaf tree species belonging to three genera with relatively high species richness, 6 Acer species, 5 Betula species and 4 Populus species.

Acer and Betula species had higher soluble sugar contents in the dormant season and indeed had higher hydraulic resilience to FTC induced embolism but slower stem growth. Populus species...