Figure 2 shows the high vertical and spatial
resolution of canopy structure that is obtained by
the advanced technology SIMPL instrument. A
single-photon point at Howland, Maine
documents structure at tree-crown scales. The
range histograms that aggregate photons acquired
over distances of 25 m reveal the canopy layers
with meter-level vertical resolution. The profile
location, in yellow is shown on a natural-color,
nadir video image acquired in-flight. The low
noise level is indicated by the count rate below
the ground.