Salinity exposure affects lower-canopy specific leaf area of upland trees in a coastal deciduous forest

Journal Article · 11 September 2023 · Forest Ecology and Management

DOI: https://doi.org/10.1016/j.foreco.2023.121404 · OSTI ID:2222457

Bond-Lamberty, Ben  ^[1]; Haddock, Lillie M. ^[1]; Pennington, Stephanie C. ^[1]; Sezen, U. Uzay ^[2]; Shue, Jessica  ^[2]; Megonigal, J. Patrick ^[2]

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1. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
2. Smithsonian Environmental Research Center, Edgewater, MD (United States)

Sea level rise and increasing storm surges are likely to affect the canopy physiology, ecology, and structure of coastal forests, even well in advance of tree mortality. Laboratory and greenhouse studies have documented that saltwater exposure can trigger changes in leaf-level physiology and morphology, but few in situ studies have examined how tree-specific leaf area (SLA), the ratio of leaf area to mass and a crucial trait and model parameter, is affected by saline soils. We conducted an observational study of SLA in a mid-Atlantic (USA) coastal deciduous forest, taking advantage of a natural gradient in salinity along a tidal creek. Measured SLA of the 239 trees and seven species sampled ranged from Carya glabra (N = 6 trees, mean SLA = 277.9±36.3cm²/g) to Fagus grandifolia (N=60, 321.9±62.9cm²g); as expected, trees species and canopy position (sun versus shade) significantly affected SLA. For trees (N=100) directly exposed to the tidal creek, salinity was highly significant after accounting for species (P<0.001), with trees in the lower reaches of the creek having lower SLA. Leaf area index (LAI), computed from SLA and litter traps, ranged from 4.8 to 15.8 and was inversely related to salinity exposure; the spatial variability in leaf litter production contributed much more to LAI uncertainty than did SLA variability. These in situ results are correlative but consistent with the hypothesis, based on previous greenhouse studies, that the stress of chronic salinity exposure changes species’ leaf morphology. Our findings are useful for understanding the growing effects of saltwater intrusion into upland forests, as well as parameterizing and testing ecosystem-scale models simulating forest stressors and disturbances at the terrestrial-aquatic interface.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC), Biological and Environmental Research (BER)
• Grant/Contract Number: AC05-76RL01830
• OSTI ID: 2222457
• Report Number(s): PNNL-SA--185828; {"","Journal ID: ISSN 0378-1127"}
• Journal Information: Forest Ecology and Management, Journal Name: Forest Ecology and Management Vol. 548; ISSN 0378-1127
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English