Volume III-8
ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., III-8, 93-99, 2016
https://doi.org/10.5194/isprs-annals-III-8-93-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., III-8, 93-99, 2016
https://doi.org/10.5194/isprs-annals-III-8-93-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

  07 Jun 2016

07 Jun 2016

EVALUATION OF VERTICAL LACUNARITY PROFILES IN FORESTED AREAS USING AIRBORNE LASER SCANNING POINT CLOUDS

B. Székely1,2,3, A. Kania4, T. Standovár5, and H. Heilmeier2 B. Székely et al.
  • 1Department of Geophysics and Space Science, Loránd Eötvös University, Budapest, Hungary
  • 2Interdisziplinäres Ökologisches Zentrum, TU Bergakademie Freiberg, Freiberg, Germany
  • 3Department of Geodesy and Geoinformation, Vienna University of Technology, Vienna, Austria
  • 4Atmoterm S.A., Opole, Poland
  • 5Department of Plant Systematics, Ecology and Theoretical Biology, Loránd Eötvös University, Budapest, Hungary

Keywords: Lacunarity, Airborne Laser Scanning, Point Clouds, Voxelization, Canopy Structure, Planted Forest

Abstract. The horizontal variation and vertical layering of the vegetation are important properties of the canopy structure determining the habitat; three-dimensional (3D) distribution of objects (shrub layers, understory vegetation, etc.) is related to the environmental factors (e.g., illumination, visibility). It has been shown that gaps in forests, mosaic-like structures are essential to biodiversity; various methods have been introduced to quantify this property. As the distribution of gaps in the vegetation is a multi-scale phenomenon, in order to capture it in its entirety, scale-independent methods are preferred; one of these is the calculation of lacunarity.

We used Airborne Laser Scanning point clouds measured over a forest plantation situated in a former floodplain. The flat topographic relief ensured that the tree growth is independent of the topographic effects. The tree pattern in the plantation crops provided various quasi-regular and irregular patterns, as well as various ages of the stands. The point clouds were voxelized and layers of voxels were considered as images for two-dimensional input. These images calculated for a certain vicinity of reference points were taken as images for the computation of lacunarity curves, providing a stack of lacunarity curves for each reference points. These sets of curves have been compared to reveal spatial changes of this property. As the dynamic range of the lacunarity values is very large, the natural logarithms of the values were considered. Logarithms of lacunarity functions show canopy-related variations, we analysed these variations along transects. The spatial variation can be related to forest properties and ecology-specific aspects.