Differences in leaf phenological traits between trees and shrubs are closely related to functional traits in a temperate forest

Leaf phenological traits vary greatly with plant species, are thought to relate to leaf functional traits, and play an important role in plant growth. In this study, we investigated leaf phenological and functional traits of 52 woody species (324 individuals) from a natural forest in the Loess Plateau in China. Shrubs obtain a longer leaf life span (LLS) through early leaf emergence and later leaf senescence. Shrubs have a longer LLS compared with trees because they have a greater leaf thickness than trees (to prevent early spring frost), leaf phosphorus content ([P](leaf), related to cell division), and C:N ratio and stem density (to prevent mechanical damage). Among all woody species, species with a small SLA and leaf area and species with thick leaves have a longer leaf emergence duration and LLS, which may be related to material energy reserves. In addition, shrubs had a greater [P](leaf) and C:N ratio and a longer leaf emergence duration. Our results reveal differences in leaf phenological traits among life forms and indicate that plant functional traits can provide insight into the mechanisms underlying such differences. In addition, the results of this study provide insight into species coexistence and community assembly in temperate deciduous forests.