Threat to maple syrup industry

The maple tree, Canada's national symbol and an important economic commodity, is threatened by climate change, according to an academic from the heart of maple country.

Robert van Hulst, an ecologist and professor of biology at Bishop's University, has studied the problem of maple dieback, a degenerative process that often leads to the death of trees that last year brought in Can$250 million (Pounds 108 million) to Quebec's economy, much of it from the export of the famous syrup.

While acid rain has been blamed for an increase in dieback in the mid-1980s, that theory does not stand up, according to Professor van Hulst.

In the study, originally started four years ago as a PhD project by ministry of environment researcher Gabriel Roy, Professor van Hulst wrote that the mortality rate in trees is too complex to be ascribed to a single cause.

"We looked at the usual culprits and stumbled on climate change," Professor van Hulst said. With co-authors including University of Sherbrooke professors Colette Ansseau and Bill Shipley, as well as Dr Roy, they observed that a combination of rainy springs and hot dry summers occurred during the highest incidence of dieback.

The study marks a turning point in the understanding of dieback and will lead to ecologists and climatologists working closer together, said Professor van Hulst. In Europe, where dieback has long been studied, a French team is already looking at the Quebec group's theory.

Bishop's University, in the province's Estrie region outside Montreal, is located in an ideal study area for Professor van Hulst, who was able to examine 150 nearby plantations of trees and study their growth rings, missing foliage and the percentage of affected trees.

While observation was the only practical means for coming to his conclusions, Professor van Hulst would still like to set up experiments, irrigating and drying up forest lots.

Unfortunately, the provincial government is not that interested in the problem of dieback, which is getting no help from the province's maple producers, an 11,000 member group.

As summers get hotter and the weather becomes more erratic, the problem is only going to get worse, said van Hulst.