LiDAR penetration through Sinharaja primary rainforest: canopy filtering and ground DEM accuracy?

Topographic mapping beneath the multi-tiered canopy of Sinharaja (where tree heights exceed 45 meters with over 90% canopy closure) requires high-pulse-rate airborne LiDAR systems (minimum 500 kHz) operating with full-waveform digitization. While early laser returns bounce off emergent Shorea crowns and intermediate tree ferns, roughly 2% to 5% of laser pulses penetrate through minute gaps in the understory foliage, striking the bare ground. Post-processing algorithms filter out dense vegetative clutter, reconstructing an accurate bare-earth Digital Elevation Model (DEM) with vertical accuracy within 15 centimeters.