The 2014 elm pruning ban in Alberta has ended for the year.

“Although Alberta remains free of DED, with two neighbouring jurisdictions, Saskatchewan and Montana battling the disease, we must stay vigilant to keep our elms healthy,” says Janet Feddes-Calpas, executive director, Society to Prevent Dutch Elm Disease.

Since its introduction from Europe in 1930, Dutch elm disease has destroyed millions of American elm trees across North America. At present, Alberta has the largest DED-free American elm stands in the world. There are an estimated 750,000 mature trees found in Alberta. One-third are in urban areas, with the remaining 500,000 in provincial parks, farm shelterbelts, and rural homesteads. The ban, which will resume April 1, is necessary during the time when DED-carrying beetles are active, which is between April and September. Fresh cuts from pruning may attract the beetles that can spread the disease, increasing the chance of an infection. Once they have infected an area, elm bark beetles will feed on healthy elms during the growing season and then breed and overwinter in dead and dying elm trees.

“The annual pruning ban is in effect during the time of year when elm bark beetles are potentially most active,” says Feddes-Calpas. “Pruning remains an important part of regular elm tree care and is encouraged in Alberta, outside of the annual ban period. Proper pruning helps keep trees healthy and better able to resist disease.”