New insights into mechanisms driving carbon allocation in tropical forests

• Published in: The New phytologist 2015, Vol.205 (1), p.137-146
• Main Authors: Hofhansl, Florian, Schnecker, Jörg, Singer, Gabriel, Wanek, Wolfgang
• Format: Article
• Language: English
• Subjects: canopy production; Carbon; Carbon - metabolism; carbon allocation; Carbon sequestration; Carbon sinks; Climate change; Dry season; Economics; Environmental changes; Environmental control; environmental controls; equations; Forest canopy; Forest ecology; Forest ecosystems; Forest soils; Forests; Geography; lowland forests; Lowlands; Mathematical models; Model testing; Models, Theoretical; Montane environments; Montane forests; Mountain forests; Multivariate statistical analysis; net primary production; Net Primary Productivity; Parameterization; Phosphorus; Plant ecology; Plant Leaves - physiology; Plants; Primary production; primary productivity; Rain; rain forests; Rainfall; Rainforest; Rainforests; Regression Analysis; root production; Seasons; Soil temperature; Temperature; Terrestrial ecosystems; Trees; Tropical Climate; Tropical forests; Tropical rain forests; tropical rainforest; Uncertainty; Wood; Wood - growth & development; wood production
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.13007

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.