Litterbugs were once the enemies of those who love Montreal's landmark mountain park but in recent years a new sort of pest has been targeted by the annual clean-up.

"Today the job is clean up the traces left by people who are inspired by mountain. They build sculptures, shelters, they move trees and rocks, so we replace the forest as it's supposed to be," said Eric Richard longtime organizer at the Friends of the Mountain group. 

The group has organized the Mount Royal clean-up since 1991 and it's no small effort. About 30 teams of 15-20 volunteers tackled the forest-saving tasks, ferried about by leaders who are sensitive to the location of rare and fragile plants and unpleasant poison ivy.

The group is also working on a number of other ongoing projects to improve the mountain, including one that aims to save the ash. One-in-three trees on Mount Royal is an ash, which has been targeted by the ash borer infestation, so teams of experts are trying to manage that threat.

Beaver Lake is still being rebuilt with a waterfall, which will be ready by the end of the summer.  "We're anxious to see that reopened," said Richard.

There are other surprises in store, including new boats. "We're going to have a more traditional way of using the lake, new kinds of boats on the lake," said Richard.