“…A higher fraction of diffuse light tends to occur due to light-scattering particles in the atmosphere, such as clouds, aerosols, and anthropogenic emissions or volcanic ejecta (Mercado et al, 2009). At the canopy level, in both agricultural and natural systems, diffuse light illuminates more total leaf area, which has been repeatedly associated with increased light use efficiency (LUE [net primary productivity divided by absorbed photosynthetically active radiation]; Gu et al, 2002;Alton et al, 2007;Urban et al, 2007Urban et al, , 2012; Alton, 2008;Kanniah et al, 2013;Williams et al, 2014;Cheng et al, 2015) and an insignificant to positive effect on primary productivity (Kanniah et al, 2012). Although studies at the individual leaf level are less common, several lines of evidence suggest that leaf developmental environment underlies internal light absorption and subsequent photosynthetic responses to diffuse versus direct light.…”