The Montréal forest: yellow birch, beech and oak

Sales of wood by landowners more than two centuries ago have caused irreversible changes in the composition of the forests of southern Québec. The beeches and yellow birches (commonly called cherry trees) have practically disappeared from several forests and been replaced by species such as hickory, which is so common today that people think they are typical of the mature forest.

This is the conclusion reached by two Université de Montréal botanists, Jacques Brisson and André Bouchard, in a study that will appear this spring in the journal Écoscience. “Until recently it was believed that the hickory-sugar maple forest was the climax forest of the Upper Saint Lawrence,” explain Mr. Bouchard, director of the Plant Biology Research Institute (IRBV). “That’s wrong. The forest that the colonists saw when they arrived here was composed of sugar maple, as well as beech, hemlock, oak, larch, yellow birch and even spruce. Since that time, many of these species can only be found occasionally or have disappeared from the region.”

To reconstitute the pre-colonial forest, the researchers had to resort to an odd methodology: a study of notarized deeds kept in the municipal and provincial archives. You have to bear in mind that the population of Lower Canada was not well educated in the early days; notaries officiated at all commercial transactions. For example, the sale of a pile of wood for heating or construction was commonly recorded in a deed of sale signed by a notary. The deed contained details of the species of wood sold, the volume, price, etc. After searching through some 500,000 notarized deeds, the archivist-botanists selected 119 acts for detailed study. Since the land has been surveyed accurately since the beginning of colonization, they were able to locate 60 woodlots from the beginning of the 19th century that had not been converted to pasture, cornfields or highways. With the old records, they could compare the old growth forests with today’s forests—a real journey in time. “We noted that human activity for close to two centuries, especially between 1820 and 1840, was enough to make the beech and yellow birch disappear almost completely,” note Mr. Brisson.

Jacques Brisson and André Bouchard confirmed their hypothesis when they examined the composition of the Muir’s forest, one of the only wooded areas in the Saint Lawrence plain that has been spared direct human intervention. Here they found beeches and maples dating back 250 years or more. “Some were there at the time the first colonists arrived,” mentions Jacques Brisson, who discovered this amazing forest during his master’s degree studies. The Muir’s forest is now a protected space—and a Université de Montréal open-air laboratory. Mr. Brisson, a professor in the Department of Biology and a researcher at the IRBV, has conducted several studies in this forest.

Researcher: Jacques Brisson
Telephone: (514) 872-1437
Funding: Natural Sciences and Engineering Research Council of Canada


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