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Higher carbon storage in primary than secondary boreal forests in Sweden

Pascual, Didac LU ; Hugelius, Gustaf ; G. Canadell, Josep ; Harden, Jennifer ; Jackson, Robert B. ; Georgiou, Katerina ; Jonshagen, Anders ; Lindström, Johan LU orcid ; Ljung, Karl LU orcid and Register, Emily LU , et al. (2026) In Science 391(6791). p.1256-1261
Abstract
INTRODUCTION
Boreal forests are crucial for mitigating global climate change by capturing and storing large amounts of atmospheric carbon dioxide. However, previously unmanaged primary boreal forests are being rapidly transformed to managed secondary forests to meet the rising global demand for materials and energy. Understanding the effects of boreal primary to managed secondary forest transformations on carbon (C) storage is critical for constraining the global C budget and for evaluating the potential of northern forests in climate change mitigation strategies, which include considerations of increased biomass use for energy and materials.
RATIONALE
Previous attempts to quantify the impacts of boreal primary to managed... (More)
INTRODUCTION
Boreal forests are crucial for mitigating global climate change by capturing and storing large amounts of atmospheric carbon dioxide. However, previously unmanaged primary boreal forests are being rapidly transformed to managed secondary forests to meet the rising global demand for materials and energy. Understanding the effects of boreal primary to managed secondary forest transformations on carbon (C) storage is critical for constraining the global C budget and for evaluating the potential of northern forests in climate change mitigation strategies, which include considerations of increased biomass use for energy and materials.
RATIONALE
Previous attempts to quantify the impacts of boreal primary to managed secondary forest transformations have been hampered by limited C storage observations. The high spatial heterogeneity in environmental characteristics and historical land use in boreal areas adds to the uncertainty and calls for regional studies. We combined Sweden’s national forest inventory data with extensive field inventories of live trees, deadwood, and soils to estimate C storage in primary and managed secondary forests in Sweden. We used multiple methods to estimate the C storage difference between primary and managed secondary forests. We added estimates of missing data on deadwood C stored in stubs and roots left on site after harvest and C stored in harvested wood products for managed secondary forests, which allowed us to compare the land C storage in primary and managed forest systems.
RESULTS
We found that primary forests store ~72% more C than managed secondary forests in vegetation, deadwood, soils, and harvested wood products combined (land C storage). Among the compartments, soils constitute both the largest C store and the largest difference between primary and managed secondary forests. Our estimated difference in land C storage between primary and managed secondary forests in Sweden is 2.7 to 8.0 times larger than reported in global state-of-the-art data-driven studies and bookkeeping models informing the Global Carbon Project.
CONCLUSION
Although the high-intensity forest management common in Sweden implies that our results may not be directly transferable to the broader boreal biome, they suggest that previous estimates have substantially underestimated the C cost of transforming primary to managed secondary boreal forests. Our findings suggest that preservation and conservation of European boreal forests may be more effective as a climate change mitigation strategy than previously thought. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Science
volume
391
issue
6791
pages
1256 - 1261
publisher
American Association for the Advancement of Science (AAAS)
ISSN
1095-9203
DOI
10.1126/science.adz8554
language
English
LU publication?
yes
id
0df5829d-fccd-4525-b0d8-83f4d33af0b3
date added to LUP
2026-03-20 11:59:49
date last changed
2026-03-24 10:18:50
@article{0df5829d-fccd-4525-b0d8-83f4d33af0b3,
  abstract     = {{INTRODUCTION<br/>Boreal forests are crucial for mitigating global climate change by capturing and storing large amounts of atmospheric carbon dioxide. However, previously unmanaged primary boreal forests are being rapidly transformed to managed secondary forests to meet the rising global demand for materials and energy. Understanding the effects of boreal primary to managed secondary forest transformations on carbon (C) storage is critical for constraining the global C budget and for evaluating the potential of northern forests in climate change mitigation strategies, which include considerations of increased biomass use for energy and materials.<br/>RATIONALE<br/>Previous attempts to quantify the impacts of boreal primary to managed secondary forest transformations have been hampered by limited C storage observations. The high spatial heterogeneity in environmental characteristics and historical land use in boreal areas adds to the uncertainty and calls for regional studies. We combined Sweden’s national forest inventory data with extensive field inventories of live trees, deadwood, and soils to estimate C storage in primary and managed secondary forests in Sweden. We used multiple methods to estimate the C storage difference between primary and managed secondary forests. We added estimates of missing data on deadwood C stored in stubs and roots left on site after harvest and C stored in harvested wood products for managed secondary forests, which allowed us to compare the land C storage in primary and managed forest systems.<br/>RESULTS<br/>We found that primary forests store ~72% more C than managed secondary forests in vegetation, deadwood, soils, and harvested wood products combined (land C storage). Among the compartments, soils constitute both the largest C store and the largest difference between primary and managed secondary forests. Our estimated difference in land C storage between primary and managed secondary forests in Sweden is 2.7 to 8.0 times larger than reported in global state-of-the-art data-driven studies and bookkeeping models informing the Global Carbon Project.<br/>CONCLUSION<br/>Although the high-intensity forest management common in Sweden implies that our results may not be directly transferable to the broader boreal biome, they suggest that previous estimates have substantially underestimated the C cost of transforming primary to managed secondary boreal forests. Our findings suggest that preservation and conservation of European boreal forests may be more effective as a climate change mitigation strategy than previously thought.}},
  author       = {{Pascual, Didac and Hugelius, Gustaf and G. Canadell, Josep and Harden, Jennifer and Jackson, Robert B. and Georgiou, Katerina and Jonshagen, Anders and Lindström, Johan and Ljung, Karl and Register, Emily and Volle, Camille and Asch, Johanna and Ervander, Ulrika and Fälthammar de Jong, Geerte and Sun, Jia and Ahlström, Anders}},
  issn         = {{1095-9203}},
  language     = {{eng}},
  number       = {{6791}},
  pages        = {{1256--1261}},
  publisher    = {{American Association for the Advancement of Science (AAAS)}},
  series       = {{Science}},
  title        = {{Higher carbon storage in primary than secondary boreal forests in Sweden}},
  url          = {{http://dx.doi.org/10.1126/science.adz8554}},
  doi          = {{10.1126/science.adz8554}},
  volume       = {{391}},
  year         = {{2026}},
}