Litterfall data and hemispherical photos for LAI-calculation on an oak stand at the Intensive Forest Monitoring Station Britz, Brandenburg, 2024 - 2025

Date of acquisition: 2024-07-12 (Leaf on) & 2025-04-16 (Leaf off) Location: Experimental Station Britz, Britz, Brandenburg, Germany DEIMS.iD: https://deims.org/8ee82a9b-5086-4547-b5aa-4064e3314762 Data products: Litterfall: Datafile: litterfall_weight.csv montly sum of leaf weight collected of 13* 0.25m² traps Method after Ukonmaanaho, L., Pitman R, Bastrup-Birk A, Breda N, Rautio P, 2020: Part XIII: Sampling and Analysis of Litterfall. Version 2020-2. In: UNECE ICP Forests Programme Co-ordinating Centre (ed.): Manual on methods and criteria for harmonized sampling, assessment, monitoring and analysis of the effects of air pollution on forests. Thünen Institute for Forests Ecosystems, Eberswalde, Germany, 18 p. + Annex [https://www.icp-forests.net/monitoring-and-research/icp-forests-manual]. Solariscope data subplot_id: 1-5 subplots Date: Date of measurement Name: Numbered name of photo & threshold Timestamp: Time of measurement DSF: Direct Site Factor ISF: Indirect Site Factor TSF: Total Site Factor Opn: Openness GapF: Gap Fraction LAI: Leaf Area Index bestthreshold: T = manual best choice of threshold to binarise between plant and sky Datafile: solariscope_data.csv Folder: rawimages: raw images used for internal processing Folder: images: processed images with 3 thresholds per subplot used for manual choice of best threshold to binarise between plant and sky Hemispherical photos date: Date of measurement time: Time of measurement cloudfraction: Cloudfraction in 1/8 steps; 8/8 means completly cloudy ev: exposure value correction of series -1,-2,-3 subplot: 1-5 subplots photonr: Numbered name of photo bestchoice: manual best choice of phot of exposure series, minimum of overexposure, maximum of exposure range Canon EOS REBEL T1i and a 5.6 mm 185° fisheye objective by Sunex, automatically horizontal levelled by an o-mount by Regent Instruments Inc., lens height above the floor is 1.3 meter red light indicates north Format: compressed: jpg and canon raw-format: cr2 Meta-Datafile hemispherical_photo.csv Folder: hemispherical_photos R-Scripts: To run the hemispherical photo processing and produce LAI results: from the repository rootRscript pcm_study_britz_hemi_photos/2025-11-26-hemispherical_photos_2_lai.R To compute LAI from litterfall and Solariscope ground-truth data: Rscript pcm_study_britz_hemi_photos/2025-11-24-litterfall2LAI.RRscript pcm_study_britz_hemi_photos/2025-11-24-solariscope2LAI.R Note: The scripts assume the repository root is the current working directory and use paths relative to the repo. If you run from elsewhere, adjust paths accordingly. output/` - Script outputs and derived visualizations: - `*_binarize_fisheye_*.png` - Binarized images generated by `binarize_fisheye()` for manual QA. - `*_gapfrac_fisheye_*.png` - Gap-fraction plots by zenith ring. - `_violine_plot_*` - Violin plots of LAI distributions by subplot or EV. - `binary_overlay_*.jpg` - Overlays between original and binary classification. - `results_LAI_from_hemispherical_photos.RData` - R data file with consolidated LAI results and objects. - `results_LAI_from_hemispherical_photos.csv` - CSV summary table with LAI metrics for each image.