Title
Assessing the Impacts of Various Factors on Treetop Detection Using LiDAR-Derived Canopy Height Models
Abstract
Canopy height models (CHMs) were utilized to detect treetops and estimate individual-tree parameters. The treetop detection based on CHMs was affected by surface topography and crown characteristics. However, their effects have not been well studied. Therefore, this paper aimed at assessing the impacts of aforementioned factors to facilitate treetop identification from LiDAR-derived CHMs. To fulfill this objective, we first extended and improved the previous models for cases with various terrains. Then, a new theoretical model was developed to quantify treetop displacements for ellipsoidal tree crowns. Finally, we further analyzed the treetop displacements due to terrain slope, crown radius, crown shape, and offset distance to the slope surface. Our analysis indicates that the vertical displacement increases exponentially with terrain slope; thus, the effect of terrain slope must be considered over extremely steep areas; larger errors are observed for trees with a large crown radius; the treetop displacements are highly correlated with crown shape, the effect of topographic normalization can be neglected for conical crowns with a large crown angle, and the elliptical crown shape can reduce the treetop detection errors; and treetop displacements increases with offset distance to the slope surface in <xref ref-type="other" rid="other1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Case 2</xref> , while opposite results are observed in <xref ref-type="other" rid="other4" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Case 5</xref> . In addition, the results also demonstrate that the effect of slope-distorted CHMs may be quite different for different types of tree crowns and terrains. Overall, this paper makes a significant contribution to the development of theoretical models for quantifying treetop displacements. Furthermore, our findings provide a theoretical basis and guidance for better identifying treetops from LiDAR-derived CHMs.
Year
DOI
Venue
2019
10.1109/TGRS.2019.2931408
IEEE Transactions on Geoscience and Remote Sensing
Keywords
Field
DocType
Vegetation,Surface topography,Biological system modeling,Shape,Forestry,Remote sensing
Remote sensing,Lidar,Mathematics,Canopy
Journal
Volume
Issue
ISSN
57
12
0196-2892
Citations 
PageRank 
References 
0
0.34
0
Authors
9
Name
Order
Citations
PageRank
Sheng Nie146.25
Cheng Wang237.89
Xiaohuan Xi33115.47
shezhou luo472.49
XiaoXiao Zhu567.26
Guoyuan Li602.70
Hua Liu700.34
Jinyan Tian8254.52
Su Zhang900.34