Crews finished up the last of the tree pruning activity in Okotoks last week, giving way to the annual elm pruning ban. The ban is in place from April 1 to Sept. 30 of each year to prevent the spread of Dutch Elm Disease. Tree pruning is done in the ‘dormant season’ to target certain harmful species and diseases, as bark beetles rest during the winter months, and cuts aren’t likely to attract them. The beetles spread the disease by carrying the Ophiostoma ulmi fungus from tree to tree… Thanks largely to those efforts, Alberta has the largest Dutch elm disease-free American elm in the world.