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Riparian forests influence stream ecosystems by controlling light availability, nutrient inputs and adding large wood (LW). While many functions of in-stream LW are well studied, there is limited research on their carbon storage potential, especially in eastern North America. Due to forest recovery following historic clearing regionally, riparian forest structure is changing, with implications for LW recruitment, accumulation and carbon dynamics. To better understand the LW carbon pool and relationships with riparian forest structure, we collected data on the forest and in-stream LW in headwater streams in the mature, northern hardwood Hubbard Brook Experimental Forest (HBEF) in New Hampshire, USA. To understand how in-stream carbon storage will change as these second-growth forests develop, we collected comparison data at streams in old-growth forests of the Adirondacks of New York State. Streams at the HBEF contained 7.5 Mg C/ha in LW (SD = 5.8 Mg C/ha), exhibiting substantial variation within and between sites. This variation is linked to heterogeneity in riparian forest structure, especially the large tree basal area. Our data suggest the storage potential of stream LW will increase as riparian forests age, with old-growth stands storing 23.8 Mg C/ha as LW (SD = 9.8). This provides a first assessment of the LW carbon pool in the region and the biotic factors that influence this storage. The positive relationship between LW carbon and large trees, and the increased storage in old-growth forests supports conservation and management that promote large trees and old forests in riparian zones. Such practices may improve the value of in-stream LW carbon as a natural climate solution.
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This content will become publicly available on December 1, 2027
Region-specific forest structure pathways reveal climate effects on old-growth tropical forest biomass
Abstract Old-growth tropical forests store vast amounts of carbon in their aboveground biomass (AGB), yet the relative roles of abiotic factors such as climate, soil, and topography in governing its spatial distribution remain poorly understood. In particular, the degree to which climate acts on AGB through forest structure is still poorly quantified at the pantropical scale. Using a pantropical dataset of more than 2,000 old-growth forest plots and a structure-explicit framework, we assess how climate influences AGB through its effects on four structural attributes: basal area, mean diameter, stem density, and basal area-weighted wood density. We find that climate shapes AGB primarily through its effects on forest structure. However, structural attributes respond to climate in opposite directions, so climate’s net effect on AGB largely cancels out, and no clear climate-AGB relationship emerges across tropical regions. Moreover, only wood density responds consistently, decreasing with annual precipitation and increasing with precipitation seasonality, whereas all other attributes respond to climate differently from one region to another. This geographical variation further obscures any global climatic signal on AGB and points to the role of biogeographic history in shaping forest structure. Our findings highlight the central role of the climate-structure nexus in explaining AGB variation, and call for structure-explicit models to improve carbon stock predictions and inform climate adaptation strategies.
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- Award ID(s):
- 2311762
- PAR ID:
- 10712057
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- Springer Nature
- Date Published:
- Journal Name:
- Scientific Reports
- Volume:
- 16
- Issue:
- 1
- ISSN:
- 2045-2322
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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