Each year, pruning of elm trees is prohibited from April 1 to August 31 to reduce the risk of Dutch elm disease (DED). The beetles that spread the deadly disease are most active during this period and are attracted to fresh cuts from pruning branches.
Regular pruning, outside the ban period, helps keep trees healthy and better able to resist all types of diseases, including DED. Removing dead and dying wood also makes trees less attractive to the elm bark beetle, the insect that spreads the fungus that causes DED.
Provincial regulations also require commercial pruners of elm trees to have taken a recognized training program or be under the supervision of someone who has. Improper pruning techniques can contribute to the spread of many tree diseases, including Dutch elm disease.
"The late summer and early fall can be an opportune time for tree maintenance" says Jeff Gooliaff, Ministry of Environment's Insect and Disease Operations Supervisor.
"The weather is generally more pleasant and predictable than in the early spring, and the leaves on the trees make it easier to spot and remove dead or unhealthy branches."
Because of the risk of spreading DED, transporting or storing elm firewood is illegal.
