“…The intensity of the fluorescence signal at canopy level depends on the photosynthetic rates, biophysical, biochemical and structural characteristics of the canopy, incoming radiation and background contributions (Cerovic et al, 1996;Damm, Guanter, Paul-Limoges et al, 2015;Damm, Guanter, Verhoef et al, 2015;Daumard et al, 2010;Fournier et al, 2012;Hoge, Swift, & Yungel, 1983;Moya, Daumard, Moise, Ounis, & Goulas, 2006;Olioso, M ethy, & Lacaze, 1992;Rossini et al, 2016;Van Wittenberghe et al, 2013;Verrelst et al, 2015). These parameters are highly variable in space and time and they should all be considered to correctly interpret the fluorescence signal.…”