London West MP Ed Holder couldn't have said it more succinctly: "Take a breath, thank a tree."

And with that advice, dozens of volunteers grabbed shovels and started digging to plant about 200 trees and shrubs on a plot of land dominated by an invasive species, buckthorn. In ReForest London's most recent project, west of Wharncliffe Rd. near the Coves environmentally significant area, the Briscoe Woods will be expanded to cover the near-barren patch of land with native trees.

"The air we breathe is the most important thing we need, which is why you're here today," said Holder, standing on a podium of compost and mulch he shared with London-Fanshawe NDP MP Irene Mathyssen Saturday under sunny skies on a warm fall day.

"This planet's hard to take care of-- but you guys get it."

Environment Canada is providing a grant of $65,000 for the group to plant 4,000 trees this year in 10 parks, including the Coves. Friends of the Coves partnered with ReForest London for the project, providing volunteers.

"This grant offers us a tremendous opportunity to plant thousands of new trees in London's parks and it encourages Londoners to help improve their environment," said Julie Ryan, executive director of ReForest London.

"Naturalizing parks provides new habitat for wildlife, improves air and water quality and enhances the natural beauty of our city."

Bill DeYoung, technical director for ReForest London, which has overseen the planting of more than 16,000 trees in the city since 2005, said the plot of land being naturalized was once dominated by buckthorn, an invasive species of plant that crowds out native species. The buckthorn was removed by the city over a two-week period last year and this year, was chipped and is being used as mulch.

The buckthorn is being replaced by a variety of trees, including sugar maples, sycamore, American plum (a wild fruit tree), dogwood, red maple, white pine and shrubs, including spicebush, ninebark, common elderberry and nannyberry. Vines will also be introduced, such as riverbank grape, fly honeysuckle and running strawberry bush.

DeYoung said acorn and hickory seeds will also be planted.

Mathyssen said trees deliver more to communities than its life breath, oxygen.

"Trees make communities better," she said. "They're not just good for the environment, but for the soul as well. And they can be community builders because, as you can see today, trees are bringing people together for something that lasts for generations."