Fig. 2From: Evaluating the impact of sampling schemes on leaf area index measurements from digital hemispherical photography in Larix principis-rupprechtii forest plotsCanopy element gap fraction (pe(θ)) obtained at four typical zenith angles (i.e. 0°, 30°, 57° and 90°) with the 13 predefined sampling schemes (SS1–SS13) in the five plotsBack to article page