Deriving Stand Structural Complexity from Airborne Laser Scanning Data—What Does It Tell Us about a Forest?

• Main Authors: Dominik Seidel, Peter Annighöfer, Martin Ehbrecht, Paul Magdon, Stephan Wöllauer, Christian Ammer
• Format: Article
• Language: English
• Published: MDPI AG 2020-06-01
• Series: Remote Sensing
• Subjects: structural complexity; airborne laser scanning (ALS); terrestrial laser scanning (TLS); threedimensional; structure; airborne
• Online Access: https://www.mdpi.com/2072-4292/12/11/1854

The threedimensional forest structure is an important driver of several ecosystem functions and services. Recent advancements in laser scanning technologies have set the path to measuring structural complexity directly from 3D point clouds. Here, we show that the box-dimension (D_b) from fractal analysis, a measure of structural complexity, can be obtained from airborne laser scanning data. Based on 66 plots across different forest types in Germany, each 1 ha in size, we tested the performance of the D_b by evaluating it against conventional groundbased measures of forest structure and commonly used stand characteristics. We found that the D_b was related (0.34 < R < 0.51) to stand age, management intensity, microclimatic stability, and several measures characterizing the overall stand structural complexity. For the basal area, we could not find a significant relationship, indicating that structural complexity is not tied to the basal area of a forest. We also showed that D_b derived from airborne data holds the potential to distinguish forest types, management types, and the developmental phases of forests. We conclude that the box-dimension is a promising measure to describe the structural complexity of forests in an ecologically meaningful way.