Why use DOAS on vegetation? Because a) nadir DOAS from aircraft or satellites needs to take into account albedo. Light-absorption by vegetation has a major impact on albedo and needs to be included into the algorithm. b) DOAS is able to detect and monitor differences in spectral absorption and reflection of vegetation in an unusual spectral resolution. This may open new aspects of research in Botany. c) the capability of DOAS to give multiple results for the same ground-pixel combined with the high repetition rate and rel. low ground-resolution of current DOAS-capable satellites makes the results interesting for direct input into global climate-models. This book gives a short introduction into the basic principles of DOAS and the botanical factors influencing vegetation spectral reflectance. It demonstrates how the new reference data was produced and shows the results of their first experimental application.