Overlooked branch turnover creates a widespread bias in forest carbon accounting

• 成果类型: Article
• 署名作者: Lim, Hyungwoo; Medvigy, David; Maekelae, Annikki; Kim, Dohyoung; Albaugh, Timothy J.; Knier, Aubrey; Blasko, Robert; Campoe, Otavio C.; Deshar, Rashila; Franklin, Oskar; Henriksson, Nils; Littke, Kim; Lutter, Reimo; Maier, Christopher A.; Palmroth, Sari; Rosenvald, Katrin; Slesak, Robert A.; Tullus, Arvo; Oren, Ram
• 署名单位: Swedish University of Agricultural Sciences; International Institute for Applied Systems Analysis (IIASA); University of Tartu; University of Notre Dame; University of Helsinki; State University of New York (SUNY) System; University at Buffalo, SUNY; Virginia Polytechnic Institute & State University; Duke University; Universidade Federal de Lavras; North Carolina State University; Tribhuvan University; University of Washington; University of Washington Seattle; Estonian University of Life Sciences; United States Department of Agriculture (USDA); United States Forest Service; United States Department of Agriculture (USDA); United States Forest Service; Duke University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9500
• DOI: 10.1073/pnas.2401035121
• 发表日期: 2024-10-15
• 关键词: horizontally heterogeneous ecosystems; norway spruce; nutrient availability; functionally diverse; demography model; loblolly-pine; balance model; scots pine; biomass; boreal

摘要

Most measurements and models of forest carbon cycling neglect the carbon flux associated with the turnover of branch biomass, a physiological process quantified for other organs (fine roots, leaves, and stems). Synthesizing data from boreal, temperate, and tropical forests (184,815 trees), we found that including branch turnover increased empirical estimates of aboveground wood production by 16% (equivalent to 1.9 Pg Cy-1 globally), of similar magnitude to the observed global forest carbon sinks. In addition, reallocating carbon to branch turnover in model simulations reduced stem wood biomass, a long- lasting carbon storage, by 7 to 17%. This prevailing neglect of branch turnover suggests widespread biases in carbon flux estimates across global datasets and model simulations. Branch litterfall, sometimes used as a proxy for branch turnover, ignores carbon lost from attached dead branches, underestimating branch C turnover by 38% in a pine forest. Modifications to field measurement protocols and existing models are needed to allow a more realistic partitioning of wood production and forest carbon storage.