Passive versus active afforestation of agricultural land: Two decades of impacts on tree biomass and ecosystem carbon storage
Abstract
Biodiversity loss and climate change are major 21st century challenges, driven by land-use change and agricultural intensification. Passive restoration through natural colonization offers a cost-effective way to recover biodiversity and carbon stocks, but its carbon sequestration potential in agricultural landscapes remains unclear. We quantified tree species composition, biomass, soil organic carbon (SOC), and ecosystem carbon stocks across four land-use types-agricultural land (year 0), naturally colonized abandoned land (21 ± 2 years), plantation forests established on former cropland (21 ± 2 years), and mature, long-term forests under active management (132 ± 11 years) in ten Danish landscapes. Biomass was estimated in 120 plots (three 400 m² plots per land-use), while SOC and ecosystem carbon stocks were quantified in 84 plots (excluding mature forests). Naturally colonized forest differed in tree species composition from mature and afforested plantations. Mature forests had the highest total wood biomass (311 ± 47 Mg ha -1 ), followed by plantations (117 ± 9 Mg ha -1 ) and naturally colonized areas (7.5 ± 2.3 Mg ha -1 ). Plantations stored more ecosystem carbon (117 ± 7 Mg ha -1 ) than naturally colonized (56 ± 3 Mg ha -1 ) or agricultural land (58 ± 7 Mg ha -1 ). The slightly lower carbon stocks in naturally colonized sites likely reflect early post-abandonment SOC dynamics (~22 years), where redistribution and initial losses of plough-layer carbon precede long-term soil carbon accumulation. While topsoil SOC (0-10 cm) did not differ among land-uses, deeper soil (10-25 cm) showed higher SOC in agricultural land compared to naturally colonized and plantation forests. Our results show that, after two decades, natural colonization promotes distinct and more diverse tree species communities, whereas plantations maximize carbon storage, highlighting the need to balance biodiversity and carbon objectives in reforestation strategies.
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BibTeX
@article{timilsina2026passive,
title = {{Passive versus active afforestation of agricultural land: Two decades of impacts on tree biomass and ecosystem carbon storage}},
author = {Sachin Timilsina and David Bille Byriel and Nathan Le Boursicaud and Davide Barsotti and Yamina Micaela Rosas and Anna Karina Zimmermann and Torben Riis-Nielsen and Inger Kappel Schmidt and Lars Vesterdal and Per Gundersen and Raphaël J Manlay and Sebastian Kepfer-Rojas},
journal = {Forest Ecology and Management},
year = {2026},
month = may,
doi = {10.1016/j.foreco.2026.123936},
url = {https://hal.inrae.fr/hal-05837561v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Passive versus active afforestation of agricultural land: Two decades of impacts on tree biomass and ecosystem carbon storage
AU - Sachin Timilsina
AU - David Bille Byriel
AU - Nathan Le Boursicaud
AU - Davide Barsotti
AU - Yamina Micaela Rosas
AU - Anna Karina Zimmermann
AU - Torben Riis-Nielsen
AU - Inger Kappel Schmidt
AU - Lars Vesterdal
AU - Per Gundersen
AU - Raphaël J Manlay
AU - Sebastian Kepfer-Rojas
PY - 2026
DA - 2026/05/27
JO - Forest Ecology and Management
DO - 10.1016/j.foreco.2026.123936
UR - https://hal.inrae.fr/hal-05837561v1
AB - Biodiversity loss and climate change are major 21st century challenges, driven by land-use change and agricultural intensification. Passive restoration through natural colonization offers a cost-effective way to recover biodiversity and carbon stocks, but its carbon sequestration potential in agricultural landscapes remains unclear. We quantified tree species composition, biomass, soil organic carbon (SOC), and ecosystem carbon stocks across four land-use types-agricultural land (year 0), naturally colonized abandoned land (21 ± 2 years), plantation forests established on former cropland (21 ± 2 years), and mature, long-term forests under active management (132 ± 11 years) in ten Danish landscapes. Biomass was estimated in 120 plots (three 400 m² plots per land-use), while SOC and ecosystem carbon stocks were quantified in 84 plots (excluding mature forests). Naturally colonized forest differed in tree species composition from mature and afforested plantations. Mature forests had the highest total wood biomass (311 ± 47 Mg ha -1 ), followed by plantations (117 ± 9 Mg ha -1 ) and naturally colonized areas (7.5 ± 2.3 Mg ha -1 ). Plantations stored more ecosystem carbon (117 ± 7 Mg ha -1 ) than naturally colonized (56 ± 3 Mg ha -1 ) or agricultural land (58 ± 7 Mg ha -1 ). The slightly lower carbon stocks in naturally colonized sites likely reflect early post-abandonment SOC dynamics (~22 years), where redistribution and initial losses of plough-layer carbon precede long-term soil carbon accumulation. While topsoil SOC (0-10 cm) did not differ among land-uses, deeper soil (10-25 cm) showed higher SOC in agricultural land compared to naturally colonized and plantation forests. Our results show that, after two decades, natural colonization promotes distinct and more diverse tree species communities, whereas plantations maximize carbon storage, highlighting the need to balance biodiversity and carbon objectives in reforestation strategies.
SN - 0378-1127
SN - 1872-7042
ER -