Individual Tree Crown Delineation from Airborne Laser Scanning for Diseased Larch Forest Stands
Airborne laser scanning (ALS) can be utilised to derive canopy height models (CHMs) for individual tree crown (ITC) delineation. In the case of forest areas subject to defoliation and dieback as a result of disease, increased irregularities across the canopy can add complications to the segmentation...
Main Authors: | , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2017-03-01
|
Series: | Remote Sensing |
Subjects: | |
Online Access: | http://www.mdpi.com/2072-4292/9/3/231 |
id |
doaj-d199935164be4d93ae6222d786f9dd9b |
---|---|
record_format |
Article |
spelling |
doaj-d199935164be4d93ae6222d786f9dd9b2020-11-24T22:58:10ZengMDPI AGRemote Sensing2072-42922017-03-019323110.3390/rs9030231rs9030231Individual Tree Crown Delineation from Airborne Laser Scanning for Diseased Larch Forest StandsChloe Barnes0Heiko Balzter1Kirsten Barrett2James Eddy3Sam Milner4Juan C. Suárez5University of Leicester, Leicester Institute for Space and Earth Observation (LISEO), Centre for Landscape and Climate Research, Department of Geography, University Road, LE1 7RH Leicester, UKUniversity of Leicester, Leicester Institute for Space and Earth Observation (LISEO), Centre for Landscape and Climate Research, Department of Geography, University Road, LE1 7RH Leicester, UKUniversity of Leicester, Leicester Institute for Space and Earth Observation (LISEO), Centre for Landscape and Climate Research, Department of Geography, University Road, LE1 7RH Leicester, UKBluesky International Limited, The Old Toy Factory, Jackson Street, Coalville, LE67 3NR Leicestershire, UKNatural Resources Wales, Clawdd Newydd, Ruthin, LL14 2NL Denbighshire, UKForest Research, Northern Research Station, Roslin, EH25 9SY Midlothian, UKAirborne laser scanning (ALS) can be utilised to derive canopy height models (CHMs) for individual tree crown (ITC) delineation. In the case of forest areas subject to defoliation and dieback as a result of disease, increased irregularities across the canopy can add complications to the segmentation of ITCs. Research has yet to address this issue in order to suggest appropriate techniques to apply under conditions of forest stands that are infected by phytopathogens. This study aimed to find the best method of ITC delineation for larch canopies affected by defoliation as a result of a Phytophthora ramorum infection. Sample plots from two study sites in Wales, United Kingdom, were selected for ITC segmentation assessment across a range of infection levels and stand characteristics. The performance of two segmentation algorithms (marker-controlled watershed and region growing) were tested for a series of CHMs generated by a standard normalised digital surface model and a pit-free algorithm, across a range of spatial resolutions (0.15 m, 0.25 m and 0.5 m). The results show that the application of a pit-free CHM generation method produced improved segmentation accuracies in moderately and heavily infected larch forest, compared to the standard CHM. The success of ITC delineations was also influenced by CHM resolution. Across all plots the CHMs with a 0.25 m pixel size performed consistently well. However, lower and higher CHM resolutions also provided improved delineation accuracies in plots dominated by larger and smaller canopies respectively. The selected segmentation method also influenced the success of ITC delineations, with the marker-controlled watershed algorithm generating significantly more accurate results than the region growing algorithm (p < 0.10). The results demonstrate that ITCs in forest stands infected with Phytophthora ramorum can be successfully delineated from ALS when a pit-free algorithm is applied to CHM generation.http://www.mdpi.com/2072-4292/9/3/231individual tree crownlidarcanopy height modelsegmentationPhytophthora ramorum |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Chloe Barnes Heiko Balzter Kirsten Barrett James Eddy Sam Milner Juan C. Suárez |
spellingShingle |
Chloe Barnes Heiko Balzter Kirsten Barrett James Eddy Sam Milner Juan C. Suárez Individual Tree Crown Delineation from Airborne Laser Scanning for Diseased Larch Forest Stands Remote Sensing individual tree crown lidar canopy height model segmentation Phytophthora ramorum |
author_facet |
Chloe Barnes Heiko Balzter Kirsten Barrett James Eddy Sam Milner Juan C. Suárez |
author_sort |
Chloe Barnes |
title |
Individual Tree Crown Delineation from Airborne Laser Scanning for Diseased Larch Forest Stands |
title_short |
Individual Tree Crown Delineation from Airborne Laser Scanning for Diseased Larch Forest Stands |
title_full |
Individual Tree Crown Delineation from Airborne Laser Scanning for Diseased Larch Forest Stands |
title_fullStr |
Individual Tree Crown Delineation from Airborne Laser Scanning for Diseased Larch Forest Stands |
title_full_unstemmed |
Individual Tree Crown Delineation from Airborne Laser Scanning for Diseased Larch Forest Stands |
title_sort |
individual tree crown delineation from airborne laser scanning for diseased larch forest stands |
publisher |
MDPI AG |
series |
Remote Sensing |
issn |
2072-4292 |
publishDate |
2017-03-01 |
description |
Airborne laser scanning (ALS) can be utilised to derive canopy height models (CHMs) for individual tree crown (ITC) delineation. In the case of forest areas subject to defoliation and dieback as a result of disease, increased irregularities across the canopy can add complications to the segmentation of ITCs. Research has yet to address this issue in order to suggest appropriate techniques to apply under conditions of forest stands that are infected by phytopathogens. This study aimed to find the best method of ITC delineation for larch canopies affected by defoliation as a result of a Phytophthora ramorum infection. Sample plots from two study sites in Wales, United Kingdom, were selected for ITC segmentation assessment across a range of infection levels and stand characteristics. The performance of two segmentation algorithms (marker-controlled watershed and region growing) were tested for a series of CHMs generated by a standard normalised digital surface model and a pit-free algorithm, across a range of spatial resolutions (0.15 m, 0.25 m and 0.5 m). The results show that the application of a pit-free CHM generation method produced improved segmentation accuracies in moderately and heavily infected larch forest, compared to the standard CHM. The success of ITC delineations was also influenced by CHM resolution. Across all plots the CHMs with a 0.25 m pixel size performed consistently well. However, lower and higher CHM resolutions also provided improved delineation accuracies in plots dominated by larger and smaller canopies respectively. The selected segmentation method also influenced the success of ITC delineations, with the marker-controlled watershed algorithm generating significantly more accurate results than the region growing algorithm (p < 0.10). The results demonstrate that ITCs in forest stands infected with Phytophthora ramorum can be successfully delineated from ALS when a pit-free algorithm is applied to CHM generation. |
topic |
individual tree crown lidar canopy height model segmentation Phytophthora ramorum |
url |
http://www.mdpi.com/2072-4292/9/3/231 |
work_keys_str_mv |
AT chloebarnes individualtreecrowndelineationfromairbornelaserscanningfordiseasedlarchforeststands AT heikobalzter individualtreecrowndelineationfromairbornelaserscanningfordiseasedlarchforeststands AT kirstenbarrett individualtreecrowndelineationfromairbornelaserscanningfordiseasedlarchforeststands AT jameseddy individualtreecrowndelineationfromairbornelaserscanningfordiseasedlarchforeststands AT sammilner individualtreecrowndelineationfromairbornelaserscanningfordiseasedlarchforeststands AT juancsuarez individualtreecrowndelineationfromairbornelaserscanningfordiseasedlarchforeststands |
_version_ |
1725648204951715840 |