Bright Future for Hybrid Poplars.

When John Kort puts his arms around a tall poplar at the Indian Head PFRA Shelterbelt Centre, he's simply measuring it and not hugging it like a lost Boy Scout.

After talking with him for a few hours, it's understandable why the fast-growing poplar has gotten the attention of thousands of farmers, environmentalists and the pulp and paper industry.

Research funded by the Canada-Saskatchewan Agri-Food Innovation Fund (AFIF) discovered that new poplars inexpensively and effectively reduce greenhouse gas emissions from the air at a remarkable rate. Recently developed hybrid poplar clones have also shown potential as an alternative to aspen for Saskatchewan's wood processing industry.

"Poplars have been planted in prairie farmstead shelterbelts plus wildlife and field shelterbelts for many years," said Kort, a shelterbelt biologist and agroforester with Agriculture and Agri-Food Canada.

Many of the five million trees and shrubs distributed to almost 8,000 clients last spring were poplars well adapted to the short growing season on the Prairies.

"They've been selecting poplar because of their fast growth, but the future for poplars may be even brighter," said Kort.

Researchers now have quantified the amount of harmful carbon dioxide poplars remove from the atmosphere. This information may prove invaluable if shelterbelts on the Prairies are identified as a form of "afforestation", a term used in the Kyoto Protocol on greenhouse gases as one acceptable way of removing carbon dioxide from the atmosphere. Scientists refer to this capability as a carbon sink.

One Centre study looked at the above ground biomass of seven types of mature trees located in 63 shelterbelts. Since caragana is the main shrub used in prairie shelterbelts, they were also measured.

"Hybrid poplars were found to be the fastest accumulator of carbon dioxide, the greatest water user and the largest tree," said Kort. "Poplars are an excellent carbon sink. The poplar far outpaced its nearest rivals in the brown, dark brown or black soil zones."

These trees remove carbon dioxide from the air, store it in the wood and release oxygen.

"Just one poplar shelterbelt tree in the black soil zone absorbs more than two tonnes of carbon dioxide during its lifetime," Kort said. "Poplars grown in a shelterbelt have greater access to light and moisture than those grown under plantation conditions."

Poplars thrive in the black soil zone, which covers much of the boreal transition ecoregion and the Aspen Parkland Region in southeast Saskatchewan. However, given the right soil and enough water, poplars can grow successfully anywhere in southern Saskatchewan.

Another of Kort's projects involved five different hybrid poplars planted on 45 acres at three sites. He found the 'Walker' hybrid poplar the clear winner. Some of the Walker poplars grown in loamy soils in the north grew five metres in four years.

"We had to get some plantations in the ground to understand the issues: how to plant, maintain, space and clone," said Kort.

With these plantations, scientists are able to project long-term growth rates and determine the best clone and optimal spacing methods.

Walker poplars were also sampled in dozens of Saskatchewan shelterbelts, but the fastest-growing trees were generally in northern Saskatchewan where water is more accessible to the trees.

Kort and his colleagues also studied the commercial potential of the hybrid poplars for the forest products industry to see if the hybrid poplar could substitute for aspen poplar in pulp or oriented strand board (OSB).

Some day, he says, homeowners may be buying OSB with Saskatchewan hybrid poplar instead of aspen poplar for their renovation projects.