Drought responses in floodplain forests obtained by remotely sensed and tree‐ring data

Abstract

Forest and water-resources management in floodplains requires an understanding of the nature of drought specific to ecosystems there. The complex relationships among floodplain vegetation, topography and hydrology affect water availability. This paper investigated whether hydrological assumptions within meteorological drought indicators and ecophysiological assumptions within remote-sensing drought indicators reflect drought deficits as they occur in floodplain forests. We compared the performance of widely used meteorological and remote-sensing drought indicators in floodplain forests to tree-ring validation using five species at three floodplains in eastern Texas, USA. We found that the water balance in the Standardized Precipitation Evapotranspiration Index and the water loss estimated by the Evaporative Stress Index were useful models of water deficits in floodplain forests at the site and subsite scales, respectively. Hydrological and stand conditions varied among sites enough to affect the specific patterns of tree-species responded to drought. However, of the species we examined, tree rings in green ash were the most consistently affected by drought across floodplains and were the most closely correlated with both meteorological and remotely sensed drought indicators. Finally, drought effects varied by species and among and within floodplains, but generally, growth of trees in topographically drier sites was more closely correlated with drought indicators.

Ecohydrological interactions during drought

“…The papers span a range of water‐dependent environments: aquatic (Kupferberg et al, 2022; Sabatino et al, 2022; Saltarelli et al, 2022; White et al, 2022), floodplain (Nguyen et al, 2022), terrestrial (Belmonte et al, 2022; Castellanos et al, 2022; Gao, Wang, Li, et al, 2022; Gao, Wang, Wang, et al, 2022; He et al, 2022; Lindh et al, 2022; Parolari & Paschalis, 2022; Xu et al, 2022), wetland and pool interface (Cartwright et al, 2022; Mattei et al, 2022), and regulated, perennial, and intermittent (Di Sabatino et al, 2022; Kupferberg et al, 2022; Saltarelli et al, 2022; Sarremejane et al, 2022; Wegscheider et al, 2022) systems across both modelled‐, field‐, and lab‐based studies to address process research, cascading effects, and novel methodological approaches in ecohydrological research.…”

“…Nguyen et al (2022) examined the drought response in floodplain forests through the complex relationships among floodplain vegetation, topography, and hydrology. Using data from five tree species across three floodplains in eastern Texas, USA, they identified key meteorological and remote‐sensing drought indicators to estimate water deficits in forests across two scales.…”

“…Based on the contributions to this special issue, it becomes clear that we need to work across scales to upscale from small‐scale ecohydrological drought process understanding (Nguyen et al, 2022) to large‐scale up to continental ecohydrological drought patterns (He et al, 2022). What is also urgently required in the future are meta and comparison studies (e.g., White et al, 2022) across different water dependent terrestrial and aquatic ecosystems that allow generalization and conceptualization of process based results, this includes uncertainty assessment and providing projections.…”