Assessing fire effects on forest spatial structure using a fusion of Landsat and airborne LiDAR data in Yosemite National Park

摘要: Abstract Mosaics of tree clumps and openings are characteristic forests dominated by frequent, low- moderate-severity fires. When restoring these fire-suppressed forests, managers often try to reproduce structures increase ecosystem resilience. We examined unburned burned forest for 1937 0.81 ha sample areas in Yosemite National Park, USA. estimated severity fires from 1984 2010 using the Landsat-derived Relativized differenced Normalized Burn Ratio (RdNBR) measured canopy five height strata airborne LiDAR data. Because our study area lacked concurrent field data, we identified methods allow structural analysis data alone. found three spatial structures, canopy-gap, clump-open, open, that differed arrangement proportion openings. As fire increased, total decreased while number creating a patchwork multistory clumps. The presence > 0.3 ha, an approximate minimum gap size needed favor shade-intolerant pine regeneration, increased rapidly with loss area. range variation given were specific each type. Low- best replicated historic clump-opening patterns common frequent regimes. Our results suggest consider following goals their restoration: 1) reduce cover breaking up large contiguous into variable-sized scattered individual trees; 2) create opening sizes shapes, including ~ 50% open gaps > 0.3 ha; 3) addition single story clumps; 4) retain densities 5) vary treatments include mosaics across project mimic type study.