City uses USDA Northern Research Station tools to assess tree cover, quantify pollution mitigation benefits; Edmonton, Canada

City tree canopy sucks in 531 tonnes of pollution a year:
EDMONTON - A scientific survey conducted for the first time pegged the city's average tree canopy cover at 10 per cent, according to Edmonton's principal of forestry.
'I think (Edmontonians) will be surprised it's not higher,' said Jenny Wheeler. 'A lot of places, when you drive through them --like the river valley and some residential areas -- they're so well treed.'
The survey involved sampling 300 random spots in the city --whether they were in the river valley, an industrial area, or in a co-operative persons' backyard -- and calculating overall tree canopy cover based on what was in those spots. The city used a program called the Urban Forest Effects Model, developed in the late 1990s by researchers at the U.S. Department of Agriculture Forest Service. It has been used by many cities around the world. Edmonton is the fifth city in Canada to use the model, Wheeler said. Calgary was the first and calculated an average canopy cover of seven per cent, she said.