I am performing a tree census in the desert that needs to identify, measure (height), and photograph Joshua trees including, dead and fallen trees. A "boots on the ground" approach is preferred but can become very costly on large projects. I would like to use remote sensing data to perform this census. I am currently asking our drone contractor for 1' Bare Earth DEM as GeoTIFF and .las files, as well as 3" ortho photos. I can obtain almost any other data if needed.
So, my question is how can I used remote sensing data to perform this census? What additional data will I need? I have tried several methods already and have not identified or measured more than 50% of the trees against a sample area of manual "boots on the ground" survey. I would say what I have already tried but I am afraid that would limit answers. I have a little experience with remote sensing data (mostly topo) but have never needed this level of detail or analysis before.
I know that getting photos is probably a stretch.