title: Allocation of gross primary production in forest ecosystems: allometric constraints and environmental responses.
abstract: Understanding the allocation of gross primary production (GPP) and its response to climate is essential for improving terrestrial carbon (C) modelling. Here, we synthesize data on component GPP fluxes from a worldwide forest database to determine the allocation patterns of GPP across global gradients in climate and nitrogen deposition (Ndep ). Our results reveal that allocation of GPP is governed in an integrated way by allometric constraints and by three trade-offs among GPP components: wood production (NPPwood ) vs fine-root production (NPPfroot ), NPPwood vs foliage production (NPPfoliage ), and autotrophic respiration (Ra ) vs all biomass production components. Component fluxes were explained more by allometry, while partitioning to components was related more closely to the trade-offs. Elevated temperature and Ndep benefit long-term woody biomass C sequestration by stimulating allometric partitioning to wood. Ndep can also enhance forest C use efficiency by its effects on the Ra vs biomass production trade-off. Greater precipitation affects C allocation by driving the NPPwood vs NPPfoliage trade-off toward the latter component. These results advance our understanding about the global constraints on GPP allocation in forest ecosystems and its climatic responses, and are therefore valuable for simulations and projections of ecosystem C sequestration.
authors.affiliation: Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), School of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China; Institute of Biological & Environmental Sciences, School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 3UU, UK.
authors.forename: Guangshui
authors.initials: G
authors.lastname: Chen
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Yang
authors.forename: David
authors.initials: D
authors.lastname: Robinson
mesh_terms: D017753:Ecosystem; D016018:Least-Squares Analysis; D016014:Linear Models; D008954:Models, Biological; D025341:Principal Component Analysis; D014197:Trees / Q000033:anatomy & histology* / Q000502:physiology*
keywords: assimilate allocation; carbon accumulation; climate change; forest ecosystems; optimal partitioning; plant allometry