Elucidating the role of multiple ecological drivers on tree growth represents a step towards a better understanding of forest dynamics and ecosystem function. Although abiotic and biotic factors are critical divers underlying tree growth, it remains unclear how species jointly respond to these factors vary across ontogeny (size class, canopy type, etc.) in multi-storied temperate forests.

In view of this, Dr. REN Jing, Dr. FANG Shuai, and Dr. WANG Xugao from the Institute of Applied Ecology of the Chinese Academy of Sciences, cooperating with Dr. Claire Fortunel from the Institute de Recherche pour le Développement (IRD), collected tree census data over 15 years for 42 temperate tree species with spatially-explicit soil and neighborhood crowding information in a temperate forest in northeastern China. They employed a hierarchical Bayesian model to quantify the role of soil nutrients and neighborhood crowding in determining the growth of tree species among different size classes and canopy types, and evaluate how functional traits mediate tree growth response to these drivers.

The researchers found that soil fertility increased tree growth in small trees of understory species, while neighbors show stronger negative effects on large than small trees, and on canopy than understory species. Furthermore, they found that when functional traits can mediate the effect of neighborhood crowding on tree growth across small and large trees, there is only limited evidence of trait-mediated soil effects on the growth of large trees.

These findings highlight that integrating information on tree size classes, canopy types, as well as functional traits can shed light on our understanding of community dynamics in multi-storied temperate forests.

This study entitled "Ontogeny influences tree growth response to soil fertility and neighborhood crowding in an old-growth temperate forest" was published in Annals of Botany. It was supported by the National Natural Science Foundation of China and the National Key Research and Development Program of China.

YUE Qian

Institute of Applied Ecology, Chinese Academy of Sciences 

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E-mail: yueqian@iae.ac.cn  

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