Climate and plant trait strategies determine tree carbon allocation to leaves and mediate future forest productivity. (12th June 2019)

• Record Type: Journal Article
• Authors: Trugman, Anna T.; Anderegg, Leander D. L.; Wolfe, Brett T.; Birami, Benjamin; Ruehr, Nadine K.; Detto, Matteo; Bartlett, Megan K.; Anderegg, William R. L.
• Is Part Of: Global change biology. Volume 25:Number 10(2019)
• Page Start: 3395
• Page End: 3405
• Publication Date: 2019-06-12
• Subjects: aridity gradient -- carbon allocation -- climate change -- CO2 fertilization -- leaf area -- plant hydraulic traits -- sapwood area -- vegetation model; Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.14680
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: Forest leaf area has enormous leverage on the carbon cycle because it mediates both forest productivity and resilience to climate extremes. Despite widespread evidence that trees are capable of adjusting to changes in environment across both space and time through modifying carbon allocation to leaves, many vegetation models use fixed carbon allocation schemes independent of environment, which introduces large uncertainties into predictions of future forest responses to atmospheric CO2 fertilization and anthropogenic climate change. Here, we develop an optimization‐based model, whereby tree carbon allocation to leaves is an emergent property of environment and plant hydraulic traits. Using a combination of meta‐analysis, observational datasets, and model predictions, we find strong evidence that optimal hydraulic–carbon coupling explains observed patterns in leaf allocation across large environmental and CO2 concentration gradients. Furthermore, testing the sensitivity of leaf allocation strategy to a diversity in hydraulic and economic spectrum physiological traits, we show that plant hydraulic traits in particular have an enormous impact on the global change response of forest leaf area. Our results provide a rigorous theoretical underpinning for improving carbon cycle predictions through advancing model predictions of leaf area, and underscore that tree‐level carbon allocation to leaves should be derived from first principles using mechanistic plant hydraulic processes in the next generation of vegetation models. Abstract : Forest leaf area mediates both forest productivity and tree resilience to climate extremes. Here, we develop an optimization‐based model, whereby tree carbon allocation to leaves is an emergent property of environment and plant hydraulic traits. Using a combination of meta‐analysis, observational datasets, and model predictions, we find strong evidence that optimal hydraulic–carbon coupling explains observed patterns in leaf allocation across large environmental gradients. Our results provide a theoretical underpinning for improving terrestrial productivity predictions through advancing model predictions of leaf area, and underscore that tree‐level carbon allocation to leaves should be derived from first principles using mechanistic plant hydraulic processes.