Environmental Changes and the Sugar Maple Industry

We are now coming upon a favourite season of many Canadians, maple syrup time, when nearly every market in Canada is selling their tasty maple wares. But sadly, according to a recent study, this delicious syrup may not be as plentiful in the future.

Warmer temperatures and other environmental changes could threaten the long-term sustainability of the sugar maple industry in Canada and spell its demise in the United States, according to a paper published in March 2006 by Environment Canada's Adaptation and Impacts Research Division.

The paper, entitled Atmospheric Influences on the Sugar Maple Industry in North America, summarizes the results of a preliminary study carried out by a team of Environment Canada experts using climate data from weather stations in Canada and the United States.

The sugar maple industry is unique to North America and is extremely weather sensitive. Many climatic factors influence sap production during the three to four weeks it flows each spring. The most significant of these is temperature: the air must be below freezing at night and above freezing during the day, with an optimum temperature range of -5°C to +5°C.

Other factors that influence sap production include precipitation, snow pack, mid-winter thaws, and atmospheric concentrations of carbon dioxide, ozone and acid precipitation. Sap production can be interrupted by high winds, ice storms and the quality influenced by invasive diseases and summer droughts.

The study confirms that seasonal and geographic shifts are already occurring. Reports from the eastern United States and Ontario indicate that sap flow has started up to one month earlier during the past decade compared to historical records – and that the duration of the season is decreasing. This shift in the optimum temperature range is already causing declines in sugar maple production in the United States.

Sugar maple production is also moving northward. In the mid-1800s, some southern states tapped trees, but none do now. In the past 50 years, the United States has gone from being the world's largest producer of maple products to a distant second behind Canada, whose industry was valued at $155 million in 2002.

Quebec accounts for more than 90 per cent of Canada's production. Global climate models project that the warming climate will cause sugar maple forests to shift a further 2° latitude north over this century. While this – along with the industry using a number of adaptation actions such as good forest management practices, efficient technologies for sap collection, fertilization and liming – will allow Quebec's industry to remain sustainable over the short-term (at least the next 20 years), a warming climate is expected to cause a gradual decline in the sugar maple industry in Canada over the long-term.

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