Tree recruitment is determined by stand structure and shade tolerance with uncertain role of climate and water relations

Ecology and Evolution

Peter Meyer¹  Emiel De Lombaerde²  Harald Bugmann³  Yannek Käber³  Christof Bigler³  Golo Stadelmann⁴  Jürgen Zell⁴  Jonas Stillhard⁴ 

[1] Department Forest Nature Conservation Northwest German Forest Research Institute Münden Germany;Forest & Nature Lab Department of Environment Faculty of Bioscience Engineering Ghent University Ghent Belgium;Forest Ecology Department of Environmental Systems Science Institute of Terrestrial Ecosystems ETH Zurich Zurich Switzerland;Forest Resources and Management Swiss Federal Research Institute for Forest, Snow and Landscape Research WSL Birmensdorf Switzerland;

关键词: drought tolerance;    forest ecosystems;    forest reserves;    national forest inventories;    plant population and community dynamics;    shade tolerance;   

DOI  :  10.1002/ece3.7984

来源: DOAJ

【 摘 要 】

Abstract Tree regeneration is a key process for long‐term forest dynamics, determining changes in species composition and shaping successional trajectories. While tree regeneration is a highly stochastic process, tree regeneration studies often cover narrow environmental gradients only, focusing on specific forest types or species in distinct regions. Thus, the larger‐scale effects of temperature, water availability, and stand structure on tree regeneration are poorly understood. We investigated these effects in respect of tree recruitment (in‐growth) along wide environmental gradients using forest inventory data from Flanders (Belgium), northwestern Germany, and Switzerland covering more than 40 tree species. We employed generalized linear mixed models to capture the abundance of tree recruitment in response to basal area, stem density, shade casting ability of a forest stand as well as site‐specific degree‐day sum (temperature), water balance, and plant‐available water holding capacity. We grouped tree species to facilitate comparisons between species with different levels of tolerance to shade and drought. Basal area and shade casting ability of the overstory had generally a negative impact on tree recruitment, but the effects differed between levels of shade tolerance of tree recruitment in all study regions. Recruitment rates of very shade‐tolerant species were positively affected by shade casting ability. Stem density and summer warmth (degree‐day sum) had similar effects on all tree species and successional strategies. Water‐related variables revealed a high degree of uncertainty and did not allow for general conclusions. All variables had similar effects independent of the varying diameter thresholds for tree recruitment in the different data sets. Synthesis: Shade tolerance and stand structure are the main drivers of tree recruitment along wide environmental gradients in temperate forests. Higher temperature generally increases tree recruitment rates, but the role of water relations and drought tolerance remains uncertain for tree recruitment on cross‐regional scales.

【 授权许可】

Unknown