Gap fraction 2016_BEE

Gap fraction derived from hemispherical photography at the 56 EFForTS-BEE plots: A digital camera with a fisheye lens was used to aquire images at each plot center in September and October 2016 (for details on the applied methodology see Zemp et al., 2019). The Macro "Hemispherical_2" in the software "ImageJ" (https://imagej.nih.gov/ij/) was used following recommendations by Beckschäfer et al. (2013) to transform the raw images (JPG) to black and white TIF-files, from which gap fraction (%) was estimated. The dataset contains: 1.) A results table containing Plot-IDs, the according input file names (JPG) and the output from ImageJ, i.e. the number of observed pixel-level gaps (no_of_gaps), the resulting gap area (gap_area) and the key result, i.e. the gap fraction (gap_fraction, in %). 2.) Raw input files, i.e. JPG images of the 56 plots. (filenames: "Plot [plot.nr] Photo XX.JPG"). 3.) The transformed TIF files from ImageJ, from which gap fraction was derived (filenames: "Plot [plot.nr] Photo XX_T.tif"). ------- More information about the applied methods can be found in: 1.) Zemp DC, Ehbrecht M, Seidel D, Ammer C, Craven D, Erkelenz J, Irawan B, Sundawati L, Hölscher D, Kreft H. Mixed-species tree plantings enhance structural complexity in oil palm plantations. Agriculture, Ecosystems & Environment. 2019 Nov 1;283:106564. 2.) Beschäfer, P., Seidel, D., Klein, C.: On the exposure of hemispherical photographs in forests. iForests (2013) 6: 228-237.