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Comparison of airborne laser scanning and digital stereo imagery for characterizing forest canopy gaps in coastal temperate rainforests

Authors :
Joanne C. White
Nicholas C. Coops
Michael A. Wulder
Piotr Tompalski
Source :
Remote Sensing of Environment. 208:1-14
Publication Year :
2018
Publisher :
Elsevier BV, 2018.

Abstract

Forest canopy gaps play an important role in forest dynamics. Airborne laser scanning (ALS) data provide demonstrated capacity to systematically and accurately detect and map canopy gaps over large forest areas. Digital aerial photogrammetry (DAP) is emerging as an alternative, lower-cost source of three-dimensional information for characterizing forest structure and modelling forest inventory attributes. In this study we compared the relative capacities of ALS and DAP data to map canopy gaps in a complex coastal temperate rainforest on Vancouver Island, British Columbia, Canada. We applied fixed- and variable-height threshold approaches for gap detection using both ALS and DAP data, and validated outcomes using independent data derived via visual image interpretation. Overall accuracies for ALS-derived gaps were 96.50% and 89.50% for the fixed- and variable-height threshold approaches respectively, compared to 59.50% and 50.00% for the DAP-derived gaps, with DAP data having large errors of omission (>88%). We found that 70% of ALS-derived gaps were identified in old seral stage stands (age > 250 years), while 65% of DAP-derived gaps were located in early seral stage stands (age

Details

ISSN :
00344257
Volume :
208
Database :
OpenAIRE
Journal :
Remote Sensing of Environment
Accession number :
edsair.doi...........73b8508c7c8f36f5990e5855a158a506
Full Text :
https://doi.org/10.1016/j.rse.2018.02.002