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

Abstract

The three-dimensional 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 (Db) 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 Db by evaluating it against conventional ground-based measures of forest structure and commonly used stand characteristics. We found that the Db 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 Db 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.

On the structural complexity of central European agroforestry systems: a quantitative assessment using terrestrial laser scanning in single-scan mode

“…A large variation in forest structures due to different stand managements and forest types have already been documented for our sites in earlier studies using laser scanning-based measures (cf. Ehbrecht et al 2017;Seidel et al 2020). The silvopastures were statistically not significantly different from the forest reference and only had a slightly lower mean, median and lower maximum complexity.…”

Assessing Forest Vitality and Forest Structure Using 3D Data: A Case Study From the Hainich National Park, Germany

“…The performed Kruskal-Wallis test revealed significant differences in the D b measure (D b summer-D b winter divided by D b winter) comparing all vitality groups with each other. Since the box-dimension can be derived from repeated measurements and for large areas, for example, using airborne laser scanning as shown in the previous studies (Seidel et al, 2020;Camarretta et al, 2021), it might be a useful tool to derive objective forest vitality estimates in deciduous forests. Following our case study, we suggest further research that compares the results of the leaf-on vs. leaf-off difference in boxdimension to more objective vitality indicators than the visually assessed crown defoliation.…”

Fractal-Thermodynamic System Analogy and Complexity of Plant Leaves

“…Our current understanding of the morphological diversity of biological forms is strongly dependent on the effectiveness of available geometric, computational, and information methodologies in morphometrics. Approaches to clearly and completely describe the morphology of biological forms are still challenging [20,21]. Therefore, it is essential in design studies to find a more improved and automated method that minimizes information loss and time consumption.…”