Storybank

Winter planting in wetlands may seem like a “crazy” idea — especially in northern Alberta’s boreal forest. But an OSLI-led winter planting pilot project is proving otherwise.

More than 90 per cent of black spruce seedlings survived after being planted last February as temperatures hovered around -17⁰ C to -25⁰ C, which holds great promise for revegetating wetlands disturbed by oil sands and other human activities.

“A 90 per cent survival rate would be considered a success under any planting conditions. But to have a survival rate this high for winter planting in wetlands under such extreme conditions is really incredible,” says OSLI project manager Jeremy Reid.

“After we planted, the temperature dropped to below -30⁰ C, which caused some concern. But we didn’t baby the seedlings so we know weather conditions won’t be an issue in the seedlings’ survival when we scale this up to larger areas.”

Reid points out little experimental work has been carried out on revegetating wetlands, which are difficult to access for planting trees during the spring, summer and fall due to the muddy nature of thawed muskeg. And even if trees are planted, many simply become oversaturated because surface water patterns are often altered on disturbed wetlands.

“This approach is innovative because it involves winter planting of a non-commercial species in a wetland area where substantial site preparation was carried out to modify the site’s hydrology in order to increase the chance of successful tree growth.”

About 900 black spruce seedlings were planted in about 300 hummock-like mounds, 30-40 cm in height, constructed from the frozen muskeg using a backhoe. The mounds were created so the seedlings could take root and not be overcome by water produced during spring melt. Two seedlings were planted in each mound, one at a depth of 5-7 cm and the other at 10-12 cm.

“The mounds played an important role in the survival of the seedlings. Mortalities occurred where the mounds had shifted, exposing the roots to the air.”

As a result, in future projects the mounds will be more compacted to reduce shifting. It’s also critical to keep the roots of the seedlings at temperatures around -5⁰ C during transportation, storage and planting.

Reid says learnings from the project will be used in larger plantings now being planned for this coming winter.

The joint OSLI/government/academic planting project was carried out at the Evergreen Centre for Resource Excellence & Innovation in Evergreen Park, near Grande Prairie, Alberta. The planting trial was undertaken to improve reclamation of wetlands, particularly bogs, in the oil sands area south of Fort McMurray where Steam Assisted Gravity Drainage (SAGD) in situ operations are concentrated. Although SAGD operations cause minimal surface disruption, wetlands have been disturbed throughout the area by human activities.

“Wetlands are important for surface and water quality and animal habitat. To date, these areas have been challenging to reclaim due to the hydrology and soil properties,” says Reid, an environmental specialist with Nexen.

Tim Vinge, a landscape ecologist with Alberta Sustainable Resource Development (ASRD), says he immediately thought of winter planting to overcome wetland reclamation challenges while sitting as a government representative on the OSLI Land Stewardship Working Group.

Vinge explains winter planting was pioneered by researchers at Alberta Innovates – Technology Futures (previously Alberta Research Council) and the Caribou Range Restoration Program in North Western Alberta.

Researchers from the University of Laval in Quebec have also examined questions about the hardiness of winter-planted trees. Laval researchers took jack pine, white spruce and black spruce seedlings that had been stored at -3⁰ C and then put them in a freezer for twelve hours at different temperatures. The black spruce and white spruce had minimal damage. Black spruce was the least impacted species and was able to survive -35⁰ C temperatures.

“The black spruce came out smelling like a rose. Even in -35⁰ C they didn’t blink.”

Vinge says black spruce, a slow-growing tree indigenous to Alberta’s muskeg areas, has roots close to the surface so the species has evolved to the point where it can withstand low temperatures.

The pilot project involved purchasing black spruce seedlings, some 30 centimetres (cm) tall, from a nursery and transporting them to the Evergreen Centre. The Centre’s purpose is to enable industry to develop innovative resource solutions for solving environmental issues in an economically sustainable manner by researching and showcasing best practices. Dr. Weixing Tan, the principal investigator on the project from the Grande Prairie Regional College, coordinated the research for OSLI and designed the planting trial.

An above-ground mulcher prepared a 70 x 70 metre site in the park’s wetland or fen area, about the size of an oil sands exploration drilling site. Rough mulching was done in order to leave stems intact on the ground, only removing branches.  It was also important to induce a certain amount of surface frost to accommodate the excavator that would be used to construct the mounds.

Reid applauds the joint efforts of the OSLI/government/academic planting trial, which included Grande Prairie Regional College, ASRD and the Partners in Resource Excellence initiative from Alberta Environment.

“I think this study is a great example of cooperation between industry, government and academia in developing a solution to an environmental challenge,” Reid says. “We’re putting our resources together and getting on the ground to do something about it.”

Comments

• TOFIC ZHOMALI
  September 2, 2011, 12:03 pm
  very good concepts. The application will increase the RF and will decrease SOR. Pilots can show the result, but the concepts will work better than the classical SAGD

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