Betting on rains that don’t come: Monsoon failure and leaf area overshoot relate to increased tree mortality from drought

Structural overshoots, where biomass is overallocated to tree leaf area compared to sapwood area, could result in lethal stress during droughts. Climate change may alter climatic cues that drive leaf area production, such as temperature and precipitation, as well as seasonal dynamics that underlie summer rainfall due to the North American Monsoon (NAM). Combined, this could lead to temporal mismatches between leaf area-driven water demand and availability, and increased drought-induced mortality events. We used leaf area to sapwood area ratios to investigate the prevalence of overshoots and whether overshoots increase drought-induced mortality. We measured populations of aspen spanning the northern transition zone of the NAM during and following severe droughts. We observed increased overshoots and drought-induced mortality in southern latitude populations that rely more on summer monsoon rainfall. Changes in convective activity from low snowpack the preceding winter may be a climatic d..., , # Data from: Betting on rains that don’t come: Monsoon failure and leaf area overshoot relate to increased tree mortality from drought

Dataset DOI: [10.5061/dryad.vt4b8gv3q](10.5061/dryad.vt4b8gv3q)

## Description of the data and file structure

Datafiles provided for: Kerr KL, Anderegg LDLA, Trugman ATT, Anderegg WRL (2025) Betting on rains that don’t come: Monsoon failure and leaf area overshoot relate to increased tree mortality from drought

Data were gathered from national forests (NF) throughout Utah and Colorado, USA in the summers of 2014, 2018, 2019, 2020, and 2021. See Methods for specific details on measurements.

Three datasets are provided, and are described below:

Kerr_fe_2024_01119_main_dataset.csv: This file contains the main dataset used in the analyses. Among its features are tree- and plot-level values for functional traits, leaf area to sapwood area ratios, and percent canopy dieback.

Kerr_fe_2024_01119_dbh_sapwood.csv: This file contains the dataset used to gen...,