UBC Theses and Dissertations
Enhancing the characterization of forest structure and resources for forest inventory and monitoring using airborne and spaceborne single photon lidar Queinnec, Martin
Canada’s forests cover about 347 million ha, of which 157 million ha are actively managed for timber procurement and 114 million ha are located in northern remote areas and mostly unmanaged. Information about forest resources is needed to inform sustainable forest management practices and monitor the evolution of forested ecosystems, particularly in the context of climate change. In the past decades, airborne acquisitions of light detection and ranging (lidar) data have been increasingly used to map forest structure. However, their acquisitions remain expensive and coverage is often limited to targeted managed forest units. Recent technological advances led to the development of single photon lidar (SPL) systems that enable high-altitude airborne and spaceborne lidar acquisitions with an unprecedented amount of detail and across large geographic extents. Two SPL systems are currently available: the airborne SPL100 instrument, commercially released in 2017, and the spaceborne Advanced Topographic Laser Altimeter System (ATLAS) onboard the Ice Cloud and Elevation Satellite-2 (ICESat-2) launched in September 2018. However, the ability of these two systems to accurately characterize forest structure and resources is not well defined. The primary objective of this dissertation is to examine the role that SPL100 and ICESat-2 can play to provide spatially-explicit, timely and accurate estimates of some key information needs in managed and unmanaged boreal forests of Canada. To that end, an enhanced inventory of key forest attributes driven by SPL100 data was implemented across an actively managed boreal forest located in Ontario, Canada. Strengths and limitations of ICESat-2 metrics to accurately characterize canopy height, cover and vertical vegetation structure were also highlighted by comparing them to SPL100 counterparts. Moving on to a broader monitoring perspective, a method to extrapolate ICESat-2 samples of canopy height estimates across over 19 million ha of unmanaged boreal forests was implemented. Time-series of this wall-to-wall product were also produced and used to examine the recovery of vegetation height after disturbance. The research presented in this dissertation helps better understanding the ability of SPL100 and ICESat-2 to characterize vegetation structure in both managed and unmanaged forests in order to inform policy-making and sustainable forest management practices.
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Attribution-NonCommercial-NoDerivatives 4.0 International