DOI: 10.5281/zenodo.17661804
title: Litterfall data and hemispherical photos for LAI-calculation on an oak stand at the Intensive Forest Monitoring Station Britz, Brandenburg, 2024 - 2025

description: 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.