DOI: 10.7280/d1t97h
title: A compilation of canopy leaf inclination angle measurements across plant species and biome types

description: The inclination angle of leaves in plant canopies is important for a range
 of land ecosystem processes, including radiation absorption from
 vegetation, land surface reflectance, microclimate, and photosynthetic CO2
 uptake. While inclination angles of leaves have been measured for decades,
 such measurements remain scattered in the scientific literature, and the
 actual variation of leaf inclination angles across land ecosystems remains
 poorly understood and quantified. We compiled a dataset of previously
 published field measurements of mean canopy leaf angles, gathering 531
 records from 48 publications, including data from single-species and
 multi-species canopies from most major biomes. Only data from field-grown
 plants were included. When studies presented data on seasonal variation on
 mean canopy leaf angles from the same species/locations, the data were
 averaged and considered as a single record. The records were originally
 measured using several techniques, including clinometers and protractor
 measurements of individual leaves throughout the canopy, leveled
 photographs and digital measurement of individual leaves on image
 processing software, canopy hemispheric photographs, canopy analyzers
 (e.g. LAI-2000 and LAI-2200), and LIDAR. We believe this dataset is a
 valuable resource to inform studies and models that require information on
 the actual variation of this vegetation attribute.
description: We compiled measurements of mean canopy leaf inclination angles
 from published peer-reviewed scientific literature. The relevant published
 literature was collected from Scopus searches of “leaf AND angle”, “mean
 AND tilt AND angle” terms in titles, abstract and keywords, and limited
 the results to the subjects of Agricultural and Biological Sciences, Earth
 and Planetary Sciences, and Environmental Sciences. While doing the
 compilation, we tried to cover a diverse array of species and biomes.
 While this dataset does not include all existing measurements from the
 literature, it includes all of the most extensive studies and datasets
 that we are aware of. We discarded data from greenhouse and pot
 experiments, and only data from field-grown plants were included. We only
 included measurements that were representative of the whole
 plant/vegetation canopy, and excluded measurements taken from only parts
 of the canopy (e.g. measurements of sunlit leaves only were excluded).When
 studies presented data on seasonal variation on mean canopy leaf angles
 from the same species/locations, the data were averaged and considered as
 a single record. We gathered 531 records from 48 publications, including
 data from single-species and multi-species canopies from most major
 biomes. The records were originally measured using several techniques,
 including clinometers and protractor measurements of individual leaves
 throughout the canopy, leveled photographs and digital measurement of
 individual leaves on image processing software, 3D scanning, canopy
 hemispheric photographs, canopy analyzers (e.g. LAI-2000 and LAI-2200),
 and LIDAR. All records were homogenized to provide the inclination angle
 of leaves from the horizontal, i.e. 0 degrees corresponding to horizontal
 leaves and 90 degrees to vertical leaves.
description: Only basic information is provided about each record, including
 species scientific name or ecosystem type. Species name and ecosystem type
 name were not standardized in any way, and therefore it is listed as
 reported in the original reference. If further information is required
 about a specific record, the user should go to the original
 reference. Data from BROEAS have an extremely narrow
 range of variation, and we believe it arises from the technique used in
 the processing of hemispheric photographs. Therefore, we advise to be
 cautious when using the BOREAS data. See further
 details in the readme file.