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Spatially explicit global estimates of forest carbon storage are typically coarsely scaled. While useful, these estimates do not account for the variability and distribution of carbon at management scales. We asked how climate, topography, and disturbance regimes interact across and within geopolitical boundaries to influence tree biomass carbon, using the perhumid region of the Pacific Coastal Temperate Rainforest, an infrequently disturbed carbon dense landscape, as a test case. We leveraged permanent sample plots in southeast Alaska and coastal British Columbia and used multiple quantile regression forests and generalized linear models to estimate tree biomass carbon stocks and the effects of topography, climate, and disturbance regimes. We estimate tree biomass carbon stocks are either 211 (SD = 163) Mg C ha−1or 218 (SD = 169) Mg C ha−1. Natural disturbance regimes had no correlation with tree biomass but logging decreased tree biomass carbon and the effect diminished with increasing time since logging. Despite accounting for 0.3% of global forest area, this forest stores between 0.63% and 1.07% of global aboveground forest carbon as aboveground live tree biomass. The disparate impact of logging and natural disturbance regimes on tree biomass carbon suggests a mismatch between current forest management and disturbance history.
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This content will become publicly available on August 1, 2026
Different topographic and climatic contexts associated carbon hotspots in a carbon‐dense ecoregion
Abstract Forested landscapes have the potential to help offset global carbon emissions. However, current global models do not, nor are they intended to, capture the fine‐scale variability of the distributions of carbon in aboveground or belowground stocks or their simultaneous variability. Regional investigations are necessary to resolve patterns in carbon that can guide policy and planning, but regional maps that quantify multiple carbon pools are scarce. We quantified the spatial relationships of aboveground and belowground carbon stocks to understand their simultaneous variability across the forested area of the perhumid ecoregion of the Pacific Coastal Temperate Rainforest. Further, we identified topo‐climatic contexts associated with unique patterns in both aboveground and belowground carbon stocks by conducting an overlay analysis across the entire ecoregion. We utilized previously published estimates of carbon stocks based on extensive governmental data and machine learning techniques to model simultaneous spatial relationships of aboveground and belowground carbon stocks and generate a map for a high carbon region. We employed Pearson's correlations as well as ANOVA and Tukey honestly significant difference (HSD) tests for comparisons of topography and climate. Approximately 25% (2.6 million ha) of the area across the perhumid ecoregion had similar trends in aboveground and belowground stocks (convergence). Likewise, 20% of the ecoregion had opposite trends of aboveground and belowground stocks (divergence), and 56% of the ecoregion experienced no relationship (moderate conditions) between aboveground and belowground stocks. Convergence areas consist of carbon hotspots associated with 1.3 million ha and 794 Mg C ha−1on average, or carbon cold spots associated with 1.2 million ha and 224 Mg C ha−1. Areas with convergence, divergence, and moderate carbon stocks all had unique associations with slope, elevation, aspect, mean annual precipitation, and annual mean temperature. High levels of aboveground carbon were associated with steeper slopes, while high levels of belowground carbon were associated with high levels of precipitation. The interactions between slope, precipitation, and temperature correspond with carbon convergence and divergence, likely due to water accumulation which impacts the decomposition of organic matter in soil. These data are critical to regional planning and carbon policy and inform expectations for future carbon storage as the climate changes.
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- Award ID(s):
- 2025726
- PAR ID:
- 10644021
- Publisher / Repository:
- ESA
- Date Published:
- Journal Name:
- Ecosphere
- Volume:
- 16
- Issue:
- 8
- ISSN:
- 2150-8925
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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