Relationship between tree growth and physical dimensions of Fagus sylvatica crowns assessed from terrestrial laser scanning

Abstract

, Christian Ammer (2) Measurements of physical tree crown dimensions were of subjective character in the past, even though they can be considered important for the management of many silvicultural operations, such as timing of thinning operations. In our study we investigated if and how measures of physical crown dimensions of trees differed when quantified conventionally versus based on 3D-terrestrial laser scanning and how they are related to basal area increment. Some 24 randomly selected predominant or dominant beech trees between 90 and 110 yrs of age and of varying height were used as study trees. We hypothesized that tree crown dimensions obtained from scans are more closely related to tree radial growth than those obtained from conventional field measurements. It was found that from a variety of compared crown size characteristics the scan-based tree attributes mean crown radius, maximum area of the crown and crown projection area were most closely related to individual tree growth. We conclude that the horizontal extension of a tree crown in general is to be considered one of the most important drivers of tree growth. We also conclude that terrestrial laser scanning is a powerful tool to reliably measure physical crown dimensions and TLS-based measurements are more reliable than conventional ones.

A holistic approach to determine tree structural complexity based on laser scanning data and fractal analysis

“…In addition to such “architectural” approaches, one may assess tree structure using attributes like crown volume (Moorthy et al., ), crown surface area (Metz et al., ), tree height (Seidel, Leuschner et al., ), taper, lean and sweep of the stem (e.g., Thies, Pfeifer, Winterhalder, & Gorte, ), or crown radius (Seidel, Schall, Gille, & Ammer, ). Such morphological measures describe the growth habit, tree form or the shape of specific tree elements, or complete individuals.…”

Comparison of wood volume estimates of young trees from terrestrial laser scan data

“…In the near future, the techniques will even be available in smartphones, and solid state lidar devices will depict another option for compact lowcost 3-D point cloud data acquisition. Over the past decade a number of methods have been developed to derive common tree inventory parameters, such as DBH, TH, ground diameter (GD), and crown radii, from TLS point clouds in an automated or semi-automated fashion (Thies et al 2004, Maas et al 2008, Seidel et al 2011a, Li et al 2014, Seidel et al 2015. The extraction of wood and crown volumes, as a more complex task, has specifically advanced over recent years (Raumonen et al 2013, Bienert et al 2014, Hackenberg et al 2015b, Martin-Ducup et al 2016.…”

Morphological plant modeling: Unleashing geometric and topological potential within the plant sciences

“…These skeleton-based mathematical graphs can be derived from manual measurement (Godin et al, 1999; Watanabe et al, 2005) or imaging data (Bucksch et al, 2010; Bucksch 2011; Bucksch, 2014a; Aiteanu and Klein, 2014). Such skeletal descriptions can be used to derive quantitative measurements of lengths, diameters, and angles in tree crowns (Bucksch and Fleck, 2011; Raumonen et al, 2013; Seidel et al, 2015) and roots, at a single time point (Fitter, 1987; Danjon et al, 1999; Lobet et al, 2011; Galkovskyi et al, 2012) or over time to capture growth dynamics (Symonova et al, 2015). Having a skeletal description in place allows the definition of orders, in a biological and mathematical sense, to enable morphological analysis from a topological perspective (Figure 2A) .…”

“…Augmenting each vertex with a 3D coordinate results in a skeletal 3D representation of plant architecture derivable from imaging data (Bucksch et al, 2010; Bucksch, 2014a; Aiteanu and Klein, 2014). Such skeletal descriptions are used to derive quantitative measurements of lengths, diameters, and angles (Bucksch and Fleck, 2011; Raumonen et al, 2013; Seidel et al, 2015). Having an architectural description in place allows the definition of orders, either biologically or in a more abstract sense.…”