The city of Prince George—smack in the middle of Canada's largest softwood lumber producing region—is making wildfire protection a high priority with the management of its community forest, but it brings its own set of challenges.

By Jim Stirling - Logging and Sawmill Journal (September, 2012)

Prince George is at the heart of British Columbia's and of Canada's largest softwood lumber producing region. The forests surrounding and sustaining the city start where the last subdivision ends. Dead lodgepole pine trees—a legacy of the beetle epidemic—and a warming climate with spikes of extreme weather elevate the risk of wildfires.

Memories of what can happen with wildfire are fresh with Barriere and Kelowna in B.C. and Slave Lake in Alberta.

It's no surprise, therefore, that protection from wildfire risk is both a priority and a problem in the management of the Prince George Community Forest. The priority aspect is easy to understand; the problems, however, are more complex. In combination, they influence what the community forest can accomplish.

"We're different than most community forests with our economic ability to make money," summarizes Dan Adamson, manager of the Prince George Community Forest. "It was never intended that we could cover our costs through log harvesting revenues," he explains.

Funds to operate and maintain the 4,800 hectare community forest are sought through a variety of federal, provincial, municipal and institutional sources and are subject to regular re-application.

From the community forest's management perspective, given its finite funding, it means selecting the areas for treatment where the wildfire risk potential is highest. "It's a probability game," says Adamson. "We can only treat about 20 per cent of the forest tops and that's usually the parts of the community forest closest to homes with a significant lodgepole pine component." And prioritizing sites, as, for example, dead pine sites on steep slopes that might exacerbate a fire's spread, he points out. He reckons the sites selected for treatment cost between $14,000 and $20,000 per hectare because of the constraints imposed.

By necessity, small scale, site specific selective logging is the rule. It's not production harvesting, it's precision harvesting that's helping safeguard homes and property from wildfire.

"There lots of community and neighborhood values to accommodate. There are utility corridors and access constraints and waste management issue," notes Adamson. Burning material is not an option with airshed integrity a priority. "These huge operational constraints equate to huge costs," he says.

The Prince George Community Forest was created in 2006 and it has an allowable annual cut of 12,000 cubic metres. "We have typically cut about half of that volume, but we've harvested more because lots of that material doesn't cross a scale," explains Adamson. It's in material that ends up being chipped, for example. He estimates $9 million has been invested in the community forest since its inception and it has created jobs for about 600 people. Along the way, the safety procedures some of those people have learned and the training skills with equipment like chainsaws they have acquired have led to permanent employment within the local forest community.

The Prince George Community Forest retains Industrial Forestry Service Ltd. (IFS) in Prince George for its forestry consulting work. IFS is a long-established firm offering a wide range of forestry services.

Exactly how to safeguard an area's wildfire potential is a dynamic subject. Chunks of dried, peeling bark up to hockey puck size can create a firebrand fuel that can travel on the wind up to a kilometre, says Adamson.

"Each year we're learning new things. Fuel treatment decisions we made five years ago might now be considered too aggressive," he notes. Opening the stand and canopy can let the forest dry out too much. So the thinking with some forest fire behaviour experts is to leave more of the canopy intact to shade the forest floor, he says.

When Logging and Sawmilling Journal visited the Prince George Community Forest, a harvesting crew was working on a hillside above a subdivision fronting the Nechako River. The crew work for TDB Consultants Inc., a Prince George-based company specializing in small scale log harvesting and wildfire hazard mitigation work. TDB is the City of Prince George's prime logging contractor and the company has assembled a line-up of specialized equipment to get the job done right. "By the end of the summer when we've finished working, you won't know we've been in here," predicts Joel Bruntz, TDB's project manager.

Using low ground pressure equipment is important in an area with multiple outdoor recreation values. A Kubota KX121-3 was used to skid the hand felled trees from the bush to where the suitable stems could be accessed for loading. For longer skids, a TurboForest 42C line skidder with dual drums and Nokia tires was available on site.

TDB's site supervisor Tim Sprague was maneuvering "my baby", a small Czech-made compact Novotny forwarder. Sprague was loading pulp logs, with butts oriented forward, to be used by Canfor Corp. in its operations. The logs were bucked to Canfor's specifications of 16 feet 6 inches length. Sprague noted the Novotny's bunk can be extended to accommodate 20 foot long material. Overseeing the entire operation and ensuring all was proceeding as it should was Hunter, Sprague's bush-wise dog.

Community forest manager Adamson is investigating other initiatives to help mitigate wildfire risks around the forest. They're looking at working with local farmers with dead pine trees on their land. The idea is, he explains, to harvest the dead pine and give the net cash from the proceeds back to the farmer. It's just another way to help protect the community forest and its surroundings. Adds Adamson: "We have to adapt as we go.


Midwest Aerial Photography

Aerial Mapping - Aerial Mapping Fall '12

Case Study

Midwest Aerial Devises Custom Collection Strategy to Acquire True Orthoimagery of Canadian Capital

Concerned with the potential for building lean in aerial imagery over downtown Ottawa, Ontario, Canada’s National Capital Commission released an RFP calling for acquisition and delivery of true orthoimagery in which every pavement edge and sidewalk would be clearly visible between tall buildings. TDB Consultants Inc., a Canadian resource management firm, teamed with Midwest Aerial Photography to provide distortion-free orthomosaics that met the Commission’s stringent specifications.

“Building lean is a distortion in which tall structures appear to lean outward from the center of aerial photographs,” said Midwest Aerial President Ken Scruggs. “As a result, the ground surface immediately below the building is obscured from view.”

This creates problems for organizations that need to map infrastructure assets from air photos in downtown areas. Sidewalks, curbs, and any features on them, such as manhole covers, utilities, handicap access, and fire hydrants, are hidden from view. Such was the frustration experienced by the National Capital Commission, a Crown corporation tasked with developing, maintaining, and improving Ottawa’s Capital Region in and around its famous Parliament Hill.

For the 2011 project, the Commission sought orthoimagery covering 1,380 square kilometers of the Ottawa metropolitan area at 20-centimeter pixel resolution. Deliverables were to include natural-color orthoimages, each with accompanying digital elevation models, and a seamless mosaic. Horizontal accuracy had to meet Canada’s 1:2000 scale digital topographic mapping database with 90 percent of features located within 0.50 millimeters (at map scale) of their true positions. And the imagery had to be acquired in a tight window before leaf-out.  

TDB has a 25-year history specializing in land management, geomatics, and engineering, winning the contract to deliver the true orthoimagery. The Canadian company had worked with Midwest Aerial Photography on two earlier projects and sub-contracted the aerial portion of the Ottawa assignment to the Columbus, Ohio, firm specifying use of one of Midwest Aerial’s two Z/I Imaging DMC II-140 digital mapping cameras.

“Based on their prior experiences working with us, TDB knew the DMC II could do the job,” said Scruggs. “The DMC II provided the accuracy and geometry required for this project, and TDB appreciated how easily the digital data integrated into their image processing workflow.”

Having built its reputation in the geospatial industry as a firm that specializes in reliable aerial images and photo acquisitions regardless of tight schedules and complex airspace, Midwest Aerial left nothing to chance for the Ottawa collection. To ensure acquisition of high-quality imagery without building lean, Midwest developed a customized flight plan for the project.

The Midwest team used Google Earth to pinpoint coordinate points for every street intersection in Ottawa’s densely developed city center. These points were entered into the DMC II Z/I Mission Flight Management Software as the precise locations where each image frame would be captured. Taking into account the camera recycle rate of 2.2 seconds, Midwest calculated the frames could be successfully acquired at a ground speed of 125 knots or less from the 8,400-foot altitude above ground required for 20-cm pixel resolution. 

“We created two flight plans – one for the central business district with the tall buildings, and another for the outlying Ottawa metropolitan area,” said Scruggs. “For the central business district, we flew down every major street from the southwest to the northeast, capturing images at every intersection, which resulted in an as much as a 96 percent side lap and 93 percent forward overlap.”

By collecting images directly over every street intersection with more overlap than typically needed, Midwest Aerial ensured that every roadway, sidewalk, curb, and surface feature between the numerous tall office buildings and condominiums would be captured in multiple frames from one or more angles. The goal was to give TDB plenty of true vertical imagery to choose from when generating the orthorectified products.

The acquisition strategy worked as planned. From the 3,300 image frames collected by Midwest Aerial over Ottawa, TDB generated 345 orthorectified image scenes, which were also mosaicked into a seamless map sheet, virtually eliminating building lean, ensuring all street surfaces, pavement edges and sidewalks were fully visible even among the tallest buildings in Ottawa. 

“Our client was extremely satisfied with the product and informed us these were among the best orthoimages they had ever seen,” said Rob Kragt, TDB Director of Geomatics.

An often overlooked factor in aerial image collection that contributed to the timely delivery of end products in the Ottawa project was the quality of the aircraft location and attitude data recorded by the NovAtel SPAN GPS/IMU device used by Midwest Aerial. TDB easily ingested the GPS/IMU data into its ImageStation Aerial Triangulation software and completed the AT segment of the orthorectification process for all 3,300 image scenes in just three days.

“[We] moved onto orthophoto production and mapping within one week of receiving the materials,” said Kragt. “The end result was a product delivered on time and on budget with a very satisfied client.” 

Midwest Aerial now uses the tightly coupled GPS/IMU on all acquisition flights and finds these data sets are vital deliverables to partners and clients who are performing the image processing portion of a project.

“Attention to seemingly small details like the selection of a GPS/IMU and the creation of a custom collection strategy have a cumulative impact on the overall quality of an aerial imaging project,” said Midwest’s Scruggs.


TDB Consultants Inc., sells its shares in TDB Atlantic Inc., to Tim Nowe

In December of 2012, TDB sells all of its shares of TDB Atlantic Inc., to Tim Nowe. Tim moved out to Moncton, New Brunswick earlier in the year to take on a full management role there and now will now focus exclusively on TDB Atlantic Inc. As a result of the transaction, effective Janurary 1st, 2013, Tim Nowe will formally exit from TDB Consultants Inc.

TDB is proud of it's achievements in establishing the company in Moncton and wishes Tim Nowe continued success as he works to further TDB Atlantic's growth. 


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