Overlooked branch turnover creates a widespread bias in forest carbon accounting
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<sup>-1</sup> 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.
Authors
- Róbert Blaško (ORCID: https://orcid.org/0000-0002-2579-3903)
- Nils Henriksson (ORCID: https://orcid.org/0000-0003-1088-9192)
- Otávio Camargo Campoe (ORCID: https://orcid.org/0000-0001-9810-8834)
- David Medvigy (ORCID: https://orcid.org/0000-0002-3076-3071)
- Annikki Mäkelä (ORCID: https://orcid.org/0000-0001-9633-7350)
- Timothy J. Albaugh (ORCID: https://orcid.org/0000-0002-0216-0134)
- Rashila Deshar (ORCID: https://orcid.org/0000-0001-7866-3814)
- Robert A. Slesak (ORCID: https://orcid.org/0000-0002-6523-5383)
- Hyungwoo Lim (ORCID: https://orcid.org/0000-0001-9457-7203)
- K.M. Littke (ORCID: https://orcid.org/0000-0002-0187-1663)
- Ram Oren
- Dohyoung Kim (ORCID: https://orcid.org/0000-0002-6499-8370)
- Arvo Tullus (ORCID: https://orcid.org/0000-0002-5945-7967)
- Reimo Lutter (ORCID: https://orcid.org/0000-0001-5847-4282)
- Oskar Franklin (ORCID: https://orcid.org/0000-0002-0376-4140)
- Katrin Rosenvald (ORCID: https://orcid.org/0000-0001-7392-3867)
- Sari Palmroth (ORCID: https://orcid.org/0000-0002-1290-4280)
- Aubrey Knier (ORCID: https://orcid.org/0009-0002-4286-6745)
- Christopher A. Maier
Institutions
- University of Notre Dame (US)
- Universidade Federal de Lavras (BR)
- International Institute for Applied Systems Analysis (AT)
- University of Helsinki (FI)
- North Carolina State University (US)
- Tribhuvan University (NP)
- Duke University (US)
- Estonian University of Life Sciences (EE)
- University of Washington (US)
- Swedish University of Agricultural Sciences (SE)
- Triangle (US)
- Southern Research Station (US)
- Pacific Northwest Research Station (US)
- Slovak Environmental Agency (SK)
- University of Tartu (EE)
- Pratt Institute (US)
- University at Buffalo, State University of New York (US)
- Virginia Tech (US)
Publication Details
- Journal
- Proceedings of the National Academy of Sciences
- Published
- 2024-10-10
- DOI
- https://doi.org/10.1073/pnas.2401035121
- Citations
- 7
- Primary Topic
- Forest ecology and management
- Type
- article
- Field-Weighted Citation Impact
- 4.84
Funders
- Svenska Forskningsrådet Formas
- Eesti Teadusagentuur
- Academy of Finland
- Kempestiftelserna
- Office of Science