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Journal article
Multi-Decadal Dynamics of Forest Canopy Water Stress and GIS-Based Risk Assessment of Drought-Induced Loss in a Mediterranean-Type Forest
Remote sensing (Basel, Switzerland), Vol.18(12), 1975
2026
Abstract
What are the main findings? Landsat time-series analysis reveals a significant regime shift in the Northern Jarrah Forest towards more persistent, broader landscape-scale water stress. Denser high-rainfall stands are now more vulnerable to drought damage than structurally adapted low-rainfall stands. MaxEnt-based habitat modelling provides a robust framework for assessing drought risk to forest resources, identifying regolith depth as the primary driver of drought-induced canopy loss. What are the implications of the main findings? Forests are unlikely to recover to their 20th-century hydrological baseline, necessitating a transition from reactive monitoring to proactive management interventions, such as ecological thinning and prescribed burning, to mitigate degradation and enhance resilience. From a management perspective, particular attention should be paid to areas with shallow regolith depth, which are identified as highly vulnerable to drought-induced impacts. Mediterranean-type forest ecosystems are becoming increasingly vulnerable to intensifying drought, threatening the resilience of even highly adapted ecosystems such as the Northern Jarrah Forest in south-western Australia. This study quantifies multi-decadal dynamics of canopy water stress using a 36-year multispectral satellite archive (1988–2024) and the newly developed Infrared Canopy Dryness Index (ICDI). We combined this spatiotemporal dataset with a MaxEnt-based risk assessment framework to identify the biophysical drivers of drought-induced canopy loss and to delineate high-risk zones under accelerating climate-forcing changes. Our results demonstrate a systematic spatial expansion of canopy dryness, paralleling a deteriorating regional climatic water balance. Hotspot analysis revealed a transition from localized, peripheral stress to widespread, chronic drought conditions across the landscape. The modelling achieved high diagnostic accuracy (AUC = 0.952), significantly outperforming conventional assessment methods. Regolith depth was identified as the primary determinant of drought-induced canopy collapse, followed by ICDI, NDVI, and slope. Crucially, high-biomass stands exhibited disproportionately higher risk of collapse, revealing a density-dependent vulnerability that suggests productive forests are approaching critical hydraulic thresholds. Conversely, lower-stature forests to the east of the study area demonstrated greater stability, likely due to reduced evapotranspirative demand. These findings provide robust spatial evidence for transitioning from reactive monitoring to proactive forest management. We conclude that targeted interventions, such as ecological thinning and prescribed burning in identified high-risk zones, are imperative to protect the forest and preserve the structural integrity of Mediterranean ecosystems in a drying climate.
Details
- Title
- Multi-Decadal Dynamics of Forest Canopy Water Stress and GIS-Based Risk Assessment of Drought-Induced Loss in a Mediterranean-Type Forest
- Authors/Creators
- Le Thai SonBernard Dell - Murdoch UniversityRichard Harper - Murdoch University
- Publication Details
- Remote sensing (Basel, Switzerland), Vol.18(12), 1975
- Publisher
- MDPI
- Number of pages
- 27
- Identifiers
- 991005896971107891
- Copyright
- © 2026 by the authors.
- Murdoch Affiliation
- School of Agricultural Sciences
- Language
- English
- Resource Type
- Journal article
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