Spatially explicit assessment of multihazard exposure in the Zagros forests of Iran: the role of canopy structure in the exposure component of forest vulnerability.

Mountain forests face increasing threats from interacting climatic, environmental, and socioecological stressors, yet most vulnerability assessments still use single-hazard approaches that overlook cumulative environmental risk. This limitation is especially important in Iran's Zagros forests, where climate change and human pressures are accelerating ecological consequences. We developed a spatially explicit multihazard exposure framework to quantify forest exposure to multiple environmental stressors and assess its relationship with canopy-cover structure. Nine environmental and socioecological factors contributing to exposure, including drought, actual evapotranspiration, wildfire, high-speed winds, maximum temperature, floods, landslides, dust storms, and social vulnerability, were integrated in a GIS-based multicriteria framework using expert-derived Delphi weights. After standardization, all hazard layers were harmonized to 30 m resolution and combined to generate a high-resolution exposure index across forest landscapes. Model performance was independently validated using 448 disturbance records, including oak decline locations, field-observed degradation sites, and wildfire hotspots. Results showed strong spatial heterogeneity, with more than half of the region classified as high or very high exposure. Drought was the dominant hazard, followed by wildfire and social vulnerability, emphasizing the combined role of climatic and socioecological pressures. Exposure increased consistently as canopy cover declined, with sparsely forested stands showing the greatest concentration and continuity of high-risk zones. Validation confirmed model reliability, with 75% of disturbance records located in high and very high exposure classes. These findings highlight canopy structure as a key regulator of multihazard exposure and offer a practical decision support framework for restoration, climate adaptation, risk management, and conservation planning in climate-sensitive mountain forests worldwide.