title: Quantification of Overnight Movement of Birch (Betula pendula) Branches and Foliage with Short Interval Terrestrial Laser Scanning.
abstract: The goal of the study was to determine circadian movements of silver birch (Petula Bendula) branches and foliage detected with terrestrial laser scanning (TLS). The study consisted of two geographically separate experiments conducted in Finland and in Austria. Both experiments were carried out at the same time of the year and under similar outdoor conditions. Experiments consisted of 14 (Finland) and 77 (Austria) individual laser scans taken between sunset and sunrise. The resulting point clouds were used in creating a time series of branch movements. In the Finnish data, the vertical movement of the whole tree crown was monitored due to low volumetric point density. In the Austrian data, movements of manually selected representative points on branches were monitored. The movements were monitored from dusk until morning hours in order to avoid daytime wind effects. The results indicated that height deciles of the Finnish birch crown had vertical movements between -10.0 and 5.0 cm compared to the situation at sunset. In the Austrian data, the maximum detected representative point movement was 10.0 cm. The temporal development of the movements followed a highly similar pattern in both experiments, with the maximum movements occurring about an hour and a half before (Austria) or around (Finland) sunrise. The results demonstrate the potential of terrestrial laser scanning measurements in support of chronobiology.
authors.affiliation: Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute, National Land Survey of FinlandMasala, Finland; Department of Remote Sensing and Photogrammetry, Centre of Excellence in Laser Scanning Research, National Land Survey of FinlandMasala, Finland.
authors.forename: Eetu
authors.initials: E
authors.lastname: Puttonen
authors.affiliation: Department of Geodesy and Geoinformation, Technische Universität WienVienna, Austria; EODC Earth Observation Data Centre for Water Resources MonitoringVienna, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Briese
authors.affiliation: Department of Geodesy and Geoinformation, Technische Universität Wien Vienna, Austria.
authors.forename: Gottfried
authors.initials: G
authors.lastname: Mandlburger
authors.affiliation: Department of Geodesy and Geoinformation, Technische Universität Wien Vienna, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Wieser
authors.affiliation: RIEGL Laser Measurement Systems Horn, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Pfennigbauer
authors.affiliation: Balaton Limnological Institute, Centre for Ecological Research, Hungarian Academy of Sciences Tihany, Hungary.
authors.forename: András
authors.initials: A
authors.lastname: Zlinszky
authors.affiliation: Department of Geodesy and Geoinformation, Technische Universität Wien Vienna, Austria.
authors.forename: Norbert
authors.initials: N
authors.lastname: Pfeifer
keywords: chronobiology; circadian rhythm; plant movement; terrestrial laser scanning; time series