Up here in Alaska where most of the state is more than a hundred miles from the nearest road, the latest mapping effort has been with LiDAR in conjunction with other mapping processes. Useful in mapping, the LiDAR imagery is also useful in natural resource inventory, for it's ability to "see through" the canopy to the forest floor.
More to the point, the way that LiDAR works, it's rather good at detecting forest canopy heights. When done to higher resolutions, it can make a rather fair estimate of individual mature tree heights. While it's not very good at detecting species differences (maybe conifers versus hardwoods in a general way), work is being done to 'meld' LiDAR to other remote sensing technologies that do a good job of vegetation classification.
Being a bit of a remote sensing nut, I recall earlier National Geographics with articles on finding lost cities in the deserts of the Middle East, under sand, that yielded a wealth of archeological sites, including one at the crossroads of ancient roadways.
Don Bertolette - President/Moderator, WNTS BBS
Restoration Forester (Retired)
Grand Canyon National ParkBJCP Apprentice Beer Judge
View my Alaska Big Tree List Webpage at:http://www.akbigtreelist.org