title: New insights into mechanisms driving carbon allocation in tropical forests.
abstract: The proportion of carbon allocated to wood production is an important determinant of the carbon sink strength of global forest ecosystems. Understanding the mechanisms controlling wood production and its responses to environmental drivers is essential for parameterization of global vegetation models and to accurately predict future responses of tropical forests in terms of carbon sequestration. Here, we synthesize data from 105 pantropical old-growth rainforests to investigate environmental controls on the partitioning of net primary production to wood production (%WP) using structural equation modeling. Our results reveal that %WP is governed by two independent pathways of direct and indirect environmental controls. While temperature and soil phosphorus availability indirectly affected %WP via increasing productivity, precipitation and dry season length both directly increased %WP via tradeoffs along the plant economics spectrum. We provide new insights into the mechanisms driving %WP, allowing us to conclude that projected climate change could enhance %WP in less productive tropical forests, thus increasing carbon sequestration in montane forests, but adversely affecting lowland forests.
authors.affiliation: Department of Microbiology and Ecosystem Science, University of Vienna, Althanstraße 14, 1090, Vienna, Austria.
authors.forename: Florian
authors.initials: F
authors.lastname: Hofhansl
authors.forename: Jörg
authors.initials: J
authors.lastname: Schnecker
authors.forename: Gabriel
authors.initials: G
authors.lastname: Singer
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wanek
mesh_terms: D002244:Carbon / Q000378:metabolism*; D005843:Geography; D008962:Models, Theoretical; D018515:Plant Leaves / Q000502:physiology; D011891:Rain; D065947:Rainforest; D012044:Regression Analysis; D012621:Seasons; D013696:Temperature; D014329:Tropical Climate; D035501:Uncertainty; D014934:Wood / Q000254:growth & development
chemical_list: D002244:Carbon
keywords: canopy production; carbon allocation; environmental controls; net primary production; root production; tropical rainforest; wood production