A forested wetland at a climate-induced tipping-point: 17-year demographic evidence of widespread tree recruitment failure

• DOI: 10.1016/j.foreco.2022.120247
• Publication Date: 2022-05-06T18:55:48Z
• Authors: Jonathan Evans; Sarah McCarthy-Ne...; Angus Pritchard; Jennifer Cartwright; Bill Wolfe
• Keywords: Liquidambar styraciflua; Growing season; Basal area

Regeneration and survival of forested wetlands are affected by environmental variables related to the hydrologic regime. Climate change, specifically alterations precipitation patterns, may have outsized effects on these forests. In Tennessee, USA, has increased 15% since 1960. The goal our research was assess evidence for whether this change in patterns resulted shorter growing seasons recruitment failure common canopy trees a forest wetland. 2001 2018, density Quercus lyrata (overcup oak), Liquidambar styraciflua (sweetgum), phellos (willow Betula nigra (river birch) seedling, sapling adult were mapped an area 2.3 ha within seasonally flooded karst depression. Overall, percentage season experiencing inundation 26% greater deep than shallow areas between 2018. Saplings small adults all four species restricted areas, their abundance declined substantially. Overcup oak sweetgum individuals that recruited into life history stage repelled from zone. experienced lower mortality across 2.3-ha study (11% 26%, respectively) relative willow (56%) river birch (64%) over 17-year study. Growing-season showed no relation oak, positive among size classes overcup inverse large oak. regions, had basal increment intermediate regions pond. Results modeling area, based rainfall temperature records covering 1855–2019, show ponding durations after 1970 considerably longer historical baseline, ponding-depth classes. Our results strongly suggest climate is driving factor suppressing tree regeneration