Plant Biology

Reforesting Boucherville

On Grosbois Island, east of the Boucherville Islands National Park, a veritable open-air laboratory was set up in the spring of 2004. In three sections of a former cornfield, botanists Étienne Laliberté and Alain Cogliastro of Université de Montréal planted close to 1,300 trees last May. Small shoots of bur oak, American ash, silver maple and Eastern cottonwood are being closely watched. Reforestation strategies in this area, as well as in the whole Saint Lawrence plain, could benefit from the knowledge gained at the park.

“By the fall of 2005, we should be able to identify the most suitable strains for reforestation operations, and especially, what techniques to use,” explains Alain Cogliastro, an associate professor in the Plant Biology Research Institute of the Biology Department. “The goal is not to reproduce the forest as it was before Christopher Columbus, but to quickly produce a functional forest. We want to give nature a hand,” notes Étienne Laliberté, who is devoting his master’s thesis to this project.

The difficulty the biologists are facing have forced them to be creative. Solidago, quack grass, and thistle quickly colonized the soil when farmers abandoned the land in 2001. These invading species have left little room for species that normally make up a forest. That’s what makes the specialists’ work so promising. “The conventional reforestation technique involves running a bulldozer through it or spraying herbicides. Because we are in a national park, we could not work this way,” Mr. Cogliastro notes.

Ecological approaches were tested on plantations that had been divided into three parts. In the first, the stems were planted inside canvas sleeves; in the second, an exclosure of sticks was constructed, and the third was left wild. A third of the trees were planted in a canvas cylinder that lets light through, but not rodents; another third is protected from big mammals that might browse on the foliage, and the remaining third serves as a control culture.

If those fields had ears, they would have heard pretty positive expressions from the observers. The botanists found the young ashes performed better than the oaks, and the plants are apparently stronger in exclosures than in sleeves. One researcher, leaning over a plant in perfect health, says: “This maple grew close to 20 cm in a few weeks. Good news.” But a healthy scepticism is in order: it will all be analyzed scientifically at the end of the growing season, and further studies will be done next year, as well as in years to come.

Researcher: Alain Cogliastro
Funding: Parc des îles de Boucherville, Université de Montréal

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