In 2005, Mount Royal was declared a historic and natural district - one of the few sites in Canada to merit that double designation. But the mountain's natural environment is undergoing a profound transformation - and may be en route to disappearing altogether, says botanist Jacques Brisson, a professor at the Institut de recherche en biologie vegetale.

The forest that originally covered Mount Royal consisted of sugar maples, hickories, and red oaks. As per Brisson and master's student Joëlle Midy, sugar maples still predominate today, but Norway maples will take over in the future.

In a presentation to ACFAS on May 17, Brisson noted that a census of trees more than 10 years old found 4,200 sugar maples and 1,200 Norway maples, but the ratio was reversed in younger trees, with three times more Norway maples than sugar maples.

Fast-growing and pollution-resistant, Norway maples line the streets of Montreal. Their invasion of Mount Royal is due to a short-sighted effort to reforest parts of the park in the 1960s and '70s. The original maple trees on the upper campus are well preserved, but small Norway maples now dominate the area between the metro station and the residences.

The Norway maple closely resembles the sugar maple - in fact, it's hard to tell them apart until the leaves begin to turn. Sugar maples turn red and orange, while Norway maples turn yellow and ochre. That explains why the streets of Montreal put on a much less flamboyant show in the fall than the forests of the Laurentians or the Eastern Townships.

The Royal Canadian Mint and Canada Post have both been tripped up by the resemblance between the two. In fact, the tree shown on the penny is not a sugar maple, but "a non-existent tree," says Brisson, with the leaves shown alternating on the stalk as opposed to the way they grow in real life.

The Norway maple is now considered an invasive species in the U.S. and Ontario. Brisson plans to present a report to the City of Montreal proposing that young shoots of Norway maple be pulled up to stop the invasion.



Posted by: Erica    Source