Along Highway 116 in the Saint-Bruno district of Longueuil, a scientist looks with satisfaction at a noise barrier he erected this spring. Everything has gone as planned: in four months, the wall grew from two to three meters high. The researcher has not discovered a new kind of concrete that is capable of growing. He is a botanist, and the wall is not hard as rock but made up of a few pieces of wood, earth and, above all, willow seedlings. A first in Québec.

Michel Labrecque is head of the Research and Scientific Development Division of the Montréal Botanical Garden and a researcher at the Vegetal Biology Research Institute. An expert in tree ecophysiology, he has been working on willows for fifteen years. The willow is a fast-growing species that he has used for biomass production and soil decontamination.

The botanist is also scientific director overseeing the creation of the first “vegetalized barrier” in Québec by the Ontario firm Living Wall. Invented twenty years ago in Germany, this type of barrier has been built in a few cities in southern Ontario. The living wall represents an ecological alternative to concrete noise barriers. Michel Labrecque says that in addition to its undeniable acoustic and aesthetic qualities, it has potential to remove atmospheric pollution by fixing CO₂.

“The wall’s growth is excellent,” the botanist observes. “Now we have to hope that it will survive the rigours of our winter and all the other irritants plants have to deal with, such as spray, salt, frosts and thaws. Our wall is the northernmost of all the ones that have been built so far. We know by experience that it will preserve its acoustic qualities, even in winter when the leaves have fallen. The mass of earth and the dormant branches have an even greater anti-noise capacity than concrete walls, which are known to produce a lot of resonance.”

We will have to wait until next spring to find out whether “vegetalized walls” will be planted along other highways in Québec. Michel Labrecque hopes so.

Researcher: Michel Labrecque
Telephone: (514) 872-1862
Funding: Fonds d’action québécois pour le développement durable (financial partner: Québec government); logistical support: City of Longueuil and Québec Ministry of Transport; Living Wall (technical expertise and manpower)