(Fredericton) Anthony Taylor, a forestry professor at the University of New Brunswick, was heading down a highway in the spring of 2018 when his wife pointed out clumps of red trees. He immediately recognized that they were dead balsam fir trees.
Published at 7:05 p.m.
Hina Nature
The Canadian Press
So began a research project to examine what was killing the trees many Canadians favor for decorating their homes at Christmas.
Six years later, in an article recently published in the journal Frontiers in Forests and Global ChangeTaylor and his co-authors identified the cause of dieback in western New Brunswick and eastern Maine as drought and high temperatures caused by climate change.
“Identifying large-scale climate anomalies, such as drought, associated with sudden balsam fir mortality in 2018 could be useful in determining the likelihood of future mortality in response to climate change,” says the ‘study.
Mr. Taylor said he was shocked by such “significant” balsam fir mortality, describing the situation as “abnormal.”
The balsam fir represents approximately 20% of all trees in New Brunswick. With its scented needles and triangular shape, it is associated with Christmas. More than 95% of Christmas trees grown in the province are balsam fir. About 200,000 of them are exported, mainly to the United States.
After his observation on the highway, Mr. Taylor, along with James Broom, of the University of New Brunswick, and Loïc D’Orangeville, of Laval University, began to analyze the different causes that could have killed the trees. , including parasites and climate data.
New Brunswick experienced a drought in 2017, with hot, dry days in summer and a warm fall, and their analysis demonstrated that balsam fir is particularly sensitive to drought and high temperatures.
“This dry, hot season significantly stressed these trees and led to their demise the following year, in 2018,” Mr Taylor said.
The team also looked at historical data and found a similar weather event in 1986, when balsam fir trees died due to drought and heat the previous year. “This reaffirmed our hypothesis that climate was indeed driving the mortality we observed.” »
Fred Somerville, president of the Canadian Christmas Tree Association, points out that the balsam fir is one of the most popular trees for Christmas, the others being the Scots pine, white pine and Fraser fir. The balsam fir likes cold winters and hot, humid summers.
Mr. Somerville, who has a farm in Alliston, Ont., about 90 kilometers north of Toronto, said climate change is making the weather unpredictable.
“For the moment, it is not so much the heat as the lack of precipitation that is affecting us. Over the last decade we’ve had several years drier than we’d like to see, but the last two years haven’t been too bad,” he argued.
Lack of rain kills young trees or even newly planted saplings, Somerville says. Older trees’ growth is stunted when they don’t get enough rain and they don’t have that vibrant green we look for at Christmas, he added.
New parasites appear
Matt Wright, a Christmas tree grower from Nova Scotia, noted that climate change and heat are affecting most conifers, including balsam fir, and that new pests are emerging and attacking the trees.
“Climate change has led to a change in the population dynamics of some insects, particularly those that overwinter in the soil, because we don’t have deep freezes or cold temperatures that regulate when they can emerge or even survive. »
Taylor said heat and drought have weakened balsam fir trees, making them more vulnerable to pests and disease. More research is needed to understand how climate change will affect Christmas trees, he said.
Ways to mitigate the effects of climate change include planting different species to improve forest resilience and monitoring weather conditions.
Last year was one of the hottest on record. Although balsam fir dieback like in 2018 is rare, it is likely to become more common with global warming, Taylor believes.
“The balsam fir Christmas trees we all love, we’ll have a lot less of them in 25 to 50 years, unless we do something about climate change. If we continue on the current path, there will be very few balsam fir trees left by the end of the century. »
