Canada has the world’s 4th highest estimated value of natural resources, including the world’s largest intact forested area. The Canadian Boreal Forest covers over 270 million hectares and is home to the world’s second and third largest peatland complexes. These peat-forming ecosystems contain approximately 147 Gt of soil organic carbon, equivalent to 56% of the organic carbon stored in all Canadian soils (Tarnocai 2009).
With forestry, mining, and oil and gas extraction among the most prominent industries, Canada land-use policies aim to protect the environment through a highly-regulated land reclamation process that ensures the restoration of natural ecosystems after the area has been used to extract minerals, oil or natural gas.
Canadian oil and gas companies must reclaim and monitor inactive resource extraction sites for many years after operations are completed. Land reclamation efforts are routinely evaluated through manual vegetation surveys.
To capture spatial and temporal variability across large areas, ecological surveyors set up and inspect numerous small plots, which can take a small team an entire season to survey.
The labor cost for these manual surveys is amplified by logistical difficulties, as the low-lying wetland terrain requires specialized low-ground disturbance vehicles or access via helicopter during field survey. Often they end up sampling just a subset of all the sites due to budget and logistical constraints, making it challenging and expensive to make reliable decisions about the state of reclamation efforts.
According to Dr. Cassidy Rankine, from Rankine Geospatial, a company that provides expertise in remote sensing for environmental applications, reclamation field survey is an expensive and lengthy process that can be greatly improved with the use of drone technology. Rankine has over ten years of experience working with specialized remote sensing applications from terrestrial sensor networks, unmanned aerial systems, manned aircraft, and satellite technologies. He is currently working with Dr. Bin Xu’s team of boreal peatland reclamation experts from Northern Alberta Institute of Technology (NAIT) in Edmonton, Alberta, and C-Core, a national research commercialization group based in Ottawa, Ontario to test the use of multispectral cameras for classifying peatland vegetation and estimating surface topography and hydrology to facilitate ecological reclamation efforts in the boreal Canadian landscape.
This project aims to create a framework for multispectral aerial surveys to become the new norm for reclamation vegetation surveys in peatlands. The results obtained by Dr. Xu and his team will help guide Canadian regulatory groups for oil and gas land reclamation.
“The objective is to obtain detailed vegetation community composition inventories in these boreal peatlands — which are very difficult to access by foot — to enhance and/or replace the current ground plot survey work being done over very large areas in the boreal forest in Canada,” says Rankine.
In an effort to test how effective drone-technology is for reclamation, Rankine partnered with UAV operation experts Osprey Integrity and elected to use the MicaSense Altum on a DJI M210 to survey 4 reclamation research areas (2,000 acres total) near the town of Peace River in northern Alberta.
Rankine and the team at Osprey performed two separate UAV survey campaigns in July 2019 and October 2019, in order to capture spectral reflectance data across the different seasons that may indicate different layers of vegetation and changes in hydrology patterns.
“We used Altum because it offered the ability to obtain reliable spectral reflectance data with the fine spatial resolution required for standardized time series analysis — the Altum camera and the incident light sensor technology offered the best option for spatial, spectral and temporal analysis for accurate and meaningful vegetation surveys in this kind of landscape”.
Tens of thousands of images from dozens of flights were processed using Pix4D to produce sub-decimeter reflectance orthomosaics in 6 spectral bands of each site. The team also used ground control coordinates from a sub-centimeter RTK Wingtra survey orthomap that was processed in parallel to avoid the need to collect in-situ ground control points.
This high accuracy positioning of the data allowed for repeatable comparison of the orthomaps in order to properly measure changes over time in the landscape vegetation at the fine spatial resolution required for peatland plant community analysis.
The first results indicated that the use of UAVs with the Altum sensor generated repeatable measurements, and will allow for more land area to be surveyed (50x or more) with greater precision given the same amount of groundwork to evaluate the performance of these ecosystems during reclamation.
The combination of the incident light sensor and the reflectance calibration of the MicaSense Altum has enabled the development of standardized procedures for vegetation inventory assessments using unmanned aerial survey techniques, which is a huge cost-savings for the natural resource industry and for environmental groups working together to preserve these important ecosystems.
More work still needs to be done to prove the efficacy of this technology with further data analysis and additional data collection planned for 2020 for Dr. Rankine, Osprey Integrity, and the researchers at NAIT and C-Core. However, the preliminary results suggest this approach holds great promise for improving our capability to survey and assess the integrity of these carbon-rich landscapes for sustainable natural resource management in the great northern Boreal forests of Canada.