Forest Structure Drives Fuel Moisture Response across Alternative Forest States

Climate warming is expected to increase fire frequency in many productive obligate seeder forests, where repeated high-intensity can initiate stand conversion alternative states with contrasting structure. These vegetation–fire interactions may modify the direct effects of climate on microclimatic conditions that control dead fuel moisture content (FMC), which regulates activity these high-productivity systems. However, despite well-established role forest canopies buffering microclimate, interaction FMC, and their feedbacks remain poorly understood. We tested hypothesis FMC dynamics across would vary an extent meaningful for differences be attributable structural variability, important implications fire-vegetation feedbacks. was monitored at seven state forested sites were similar all aspects except type structure, two proximate open-weather stations Central Highlands Victoria, Australia. developed generalised additive mixed models (GAMMs) using daily independent autoregressive (i.e., lagged) input data test importance site properties, including lidar-derived predicting from open weather. There distinct availability (days when < 16%, dry enough sustain fire) leading positive negative fire–vegetation states. Both (r2 = 0.551) 0.936) ably predicted substantial improvement between lagged inputs included demonstrates nonindependence automated sticks level understanding temporal wet forests critical estimating FMC. observed significant random (an analogue structure effects) both (p 0.001), correlated density metrics such as light penetration index (LPI). This study states, drive flammability.