This is somehow a good post that gives me a bit of direction; Retrieving LiDAR metrics from relative vertical layers of point cloud
I'm using FUSION and rLIDAR most of the time. I'm looking for a way to detect understory crown for Individual tree. So the steps done so far, I've had done generated CHM, applied watershed delineation and extracted the raw LiDAR returns from each segmented area. Meaning i had saved all the point clouds into separate las files represent individual tree. So there's thousands of trees for my study area. Right now, i'm looking for a way to plot a histogram and get the height threshold and then separate the point clouds based on the threshold (because later i need to process the lower layer CHM for the understory).
From @Andre Silva answer in that post this is something that i can interpolate, but can anyone advice me in terms of giving me example step using R if possible on how to do this histogram profiling, thresholding thing and separate the point clouds based on the threshold.