Hot spot reflectance signatures of common boreal lichens

We present new results on the hot spot directional signature for a set of common lichen species (such as Cladina and Cladonia). This is, to our knowledge, the first laboratory experiment on the backscattering of lichen and adds to the so far sparse collection of hot spot signatures for land surfaces, especially forest understory. We report exceptionally intense backscattering surges for lichens with complex branching structure and discuss the implications for remote monitoring and the inventory of lichen abundances. Experiments were also made with surface structures modified by grinding and black paint: The significant differences in the observed hot spot peak amplitudes are strong experimental evidence that the shadow-hiding mechanism plays an important role in the backscattering enhancement for such canopy-type structures.