The Edge: Leveraging open-source LiDAR in British Columbia to prioritize legacy road terrain stability assessments

by | May 1, 2023 | 2023, Logging & Sawmilling Journal, May/June, The Edge

LidarLeveraging open-source LiDAR in British Columbia to prioritize legacy road terrain stability assessments

in B.C., many forestry roads were built in past decades on steep slopes using poor construction practices, and were then often inadequately deactivated afterwards. These locations may now pose landslide hazards which could lead to damage to people and surrounding areas. Their chance of occurrence will likely increase in the future due to projected increases in the frequency and severity of extreme rainfall events.

 

Today, there are over 36,000 kilometres of these “legacy” roads in B.C. on steep terrain, and classifying their hazards and risks requires terrain stability assessments that involve significant resources and expertise. To help address the challenge of completing assessments in a reasonable time on these legacy roads, a team of FPInnovations researchers designed a study to test a modelling-based approach to preliminary landslide hazard assessment.

The study involved developing a simple and approachable method that focused on hydrological rather than landslide modelling. This is an important simplification for the study, given that no adoption of modelling exists within terrain stability assessments done in B.C. (and North America) but some adoption does exist elsewhere in the world.

The researchers used a 2 m-resolution digital elevation model from the B.C. government’s Open LiDAR Data Portal to calculate hillslope, as well as a surface hydrology variable called specific catchment area (SCA). Points of concern were identified based on where high SCA values resulted from diversion and concentration of road drainage on steep terrain.

The promising preliminary results of a hydrologically based legacy road hazard assessment opens many possibilities that will need improvement and validation of the approach. For example, testing of other ways of using slope, SCA, and possibly even simple soil information layer to identify points (or areas) of concern may produce better results. Other fundamental work is also needed, such as increasing the number of legacy roads analyzed, looking for additional visual indicators on the ground of unstable terrain as part of field work, determining whether a higher digital elevation model resolution may be useful, and considering the benefits of landslide mapping and how this could help calibrate interpretation of SCA values.

Once improved upon and optimized, the resulting method for assessing legacy road hazards should be able to rapidly assess large regions with LiDAR coverage. This or similar modelling approaches to identifying landslide hazards may prove useful for land managers needing to prioritize detailed terrain stability assessments within areas with legacy roads, and could provide additional insight to geoscientist and engineering professionals doing the assessments.

The Open LiDAR Data Portal is an initiative from the B.C. government to make its LiDAR and associated datasets available to the public. The province’s recent commitment to continue expanding high-density LiDAR coverage via the portal could allow preliminary terrain stability assessments for the regions or the entire province as part of prioritizing treatments of the most problematic legacy roads.

report on this subject is available to the public. For more information, contact any of the report’s authors: Matt KurowskiMihai Pavel, or Allan Bradley—at matt.kurowski@fpinnovations.camihai.pavel@fpinnovations.ca and allan.bradley@fpinnovations.c a

The report can be read here: https://library.fpinnovations.ca/en/permalink/fpipub10539


Lidar

Short rotation afforestation in Canada comes full circle with findings and best practices highlighted
in three Canadian Wood Fibre Centre reports

BY TONY KRYZANOWSKI

Twenty years ago, the practice of afforestation of short rotation woody crops such as hybrid poplar was a novel concept in Canada.

It spurred considerable discussion and interest, particularly in forestry, energy and other bio-economy circles.

Many saw this technology’s potential to enhance the forest resource over a relatively short time frame while mitigating the impact of a changing climate through the development of natural carbon sinks providing new feedstocks for renewable energy and bioproduct development, enhancing wildlife habitat, helping to mitigate the occurrences of wildfires by diversifying the age and species mix of trees and the forest, providing a new potential income to landowners, and contributing to the overall well being of society by providing new cover, biofilters, and recreational environments that mimic the natural forest.

Recognizing the level of interest in this technology, the Canadian Wood Fibre Centre/Canadian Forest Service launched an initiative with a national network of partners to establish technical development sites to develop, evaluate and validate afforestation values of high yield short rotation woody crops, with the goal of establishing best practices and validating growth potential, GHG emission reduction and encouraging the development of new business endeavors.

After decades of applied research, that goal has been met and the research has come full circle, with short rotation technical development sites now having experienced their full lifecycle. The major findings and best practice suggestions of this initiative have been summarized in three publicly-available reports. These publications are:

  • “A Compendium of Operational Research – Ellerslie Short-Rotation Woody Crops Technical Development Site – Edmonton, Alberta” – authors Tim Keddy, Derek Sidders and Carmela Arevalo.

    This is a Natural Resources Canada (NRCan), Canadian Forest Service/Canadian Wood Fibre Centre publication available upon request. Information Report FI-X-024 2023.

  • “Predicting aboveground biomass carbon sequestration potential in hybrid poplar clones after afforestation plantation management in southern Ontario, Canada” – authors Amir Behzad Bazrgar, Derek Sidders and Naresh Thevathasan. This article was published in the Forestry Chronicle, 2002, VOL.98, No 1 – The Forestry Chronicle.
  • “Economic impacts of short rotation crops in Canada” – authors Torben Jensen, Tim Keddy, and Derek Sidders. This article was also published in the Forestry Chronicle, 2021, VOL. 97, No 3, The Forestry Chronicle.

The data and findings within these reports were gathered from research conducted on three primary technical development sites: in the Ellerslie area of Edmonton, Guelph, Ontario, and north of Edmonton, near St. Albert.

Research plantations within these sites fell within three categories: high yield afforestation featuring a variety of fast-growing, Canadian-bred, hybrid poplar and aspen clones; concentrated biomass featuring a variety of fast-growing willow and hybrid poplar clones; and, mixedwood afforestation, which combined high yield afforestation with a sunlight-tolerant softwood component planted in the understorey of either white spruce or white pine.

About the Edmonton Ellerslie Short Rotation Woody Crop Technical Development Site – This 18-hectare site was established in 2002 and was the primary site from which all other applied research related to this initiative across Canada evolved. It was used to develop the best practice protocols for clonal selection, species identification, plantation design, site preparation, planting, and vegetation management practices. The hardwood components having completed their lifecycle in 2018, it also served as a test case for the study of recovery operations. All told, there were 101 applied R & D focused technical development studies conducted during the full lifecycle of this site.

About the University of Guelph, Ontario Technical Development Site – Located 75 kms from Toronto and on 25 hectares at the University of Guelph, this technical development site, established in 2005 and expanded in 2009, featured clonal testing, fast growing hardwood production designs as well as mixedwood designs with white pine and spruce planted in the understorey. The site was harvested in 2019/2020, which included completion of mass and carbon analyses.

About the St. Albert, Alberta Technical Development Site – This site was established in 2009 on University of Alberta property north of Edmonton as a ‘second generation’ technical development site on agriculture/forest interface lands, representing an excellent bio-geoclimatic zone for the establishment of high yield afforestation plantations. New clones and high production poplar clones from the Ellerslie site were established and studied further on this site. The above ground biomass was recovered and measured in 2019/2020, when the trees were full-tree chipped onsite and sold to a pulp mill for the production of electricity.

For more information about these reports and sites, contact Derek Sidders at derek.sidders@nrcan-rncan.gc.ca or Tim Keddy at tim.keddy@nrcan-rncan.gc.ca.

Tony Kryzanowski

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