Abstract
The paper presents an original method for the evaluation of bark structure characteristics of tree trunks on the basis of terrestrial laser scanning data. Measurements testing the method proposed were performed in laboratory conditions for trunks of pine (Pinus sylvestris L.) and oak (Quercus robur L.). The laser scanner used was a FARO Focus 3D. The scanning was carried out in two variants for natural trunks (variant I: samples Oak-I, Pine-I) and for trunks wrapped in foil (variant II: samples Oak-II, Pine-II). The point clouds obtained were combined into a three-dimensional (3D) model, filtered, and exported to the *.xyz format in SCENE (v. 5×) software provided by FARO. For calculation of the bark structure characteristics the geoprocessing Tree Trunk Bark Structure Model (TTBSM) operating in the ArcGIS environment was developed. The mean bark height factor (BHF) of the natural pine and oak tree trunks was calculated to be 0.39 cm and 0.37 cm, while the values for the trunks wrapped in foil were 0.27 cm and 0.25 cm, respectively. The BHF of the tree trunks wrapped in foil varied in the range 0.26–0.28 cm and 0.24–0.26 cm for pine and oak, respectively, while for the natural tree trunks the range was 0.38–0.46 cm and 0.35–0.38 cm for pine and oak, respectively. The effect of BHF on the flow resistance was evaluated in a measuring trough and proved to be significant. The coefficient of flow resistance was on average 20% higher for the natural tree trunks than for those foil-wrapped.
Highlights
Many authors have carried out research on the impact of vegetation on flow conditions in open channel flow
In the step, using the Tree Trunk Bark Structure Model (TTBSM) model, the point clouds were divided into segments 0.05 m width, resulting in eight segments which were used in the analysis (Figure 5A)
Our results showed that the tree trunk bark structure increases the flow resistance of trees by about 20% compared to tree trunks wrapped in foil
Summary
Many authors have carried out research on the impact of vegetation on flow conditions in open channel flow. The studies concern derivation of theoretical principles of the mathematical modeling of the phenomenon [1,2,3,4,5], numerical modeling with models of varying complexity [6,7,8], flume experiments to verify models of vegetation roughness [9,10,11], and in situ floodplain roughness estimations [12]. The roughness calibration of floodplains and channels is an important issue in flood studies [14]. Riparian vegetation plays a crucial role affecting the floodplain hydraulic roughness [15]. Vegetation roughness, and forest roughness, is a necessary component in more accurate determination of flood dynamics [16]. Tree trunks are major contributors to the roughness coefficient in
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