FREDERICTON - University of New Brunswick forestry professor Anthony Taylor was heading down a highway in the spring of 2018 when his wife pointed out clumps of red-coloured trees.
Taylor recognized them as dead balsam firs, and so began a research project to examine what was killing the trees favoured by many Canadians to decorate their homes at Christmas.
Six years later, in a paper recently published in the journal "Frontiers in Forests and Global Change," Taylor and his co-authors identify the cause of the die-off in western New Brunswick and eastern Maine as drought and high temperatures brought on by climate change.
"Identifying the broad scale climate anomalies, such as a drought, associated with the reported sudden balsam fir mortality in 2018 could prove useful to determine the likelihood of future mortality in response to climate change," the study says.
Taylor said he was shocked by "that much" death of balsam firs.
"It's quite, quite abnormal to have such wide-scale death of these balsam fir trees," he said in a recent interview. "And it really stood out."
The balsam fir accounts for about 20 per cent of all trees in New Brunswick. But with its fragrant needles and triangular shape, the tree is most commonly associated with Christmas.
More than 95 per cent of Christmas trees grown in the province are balsam fir and about 200,000 of those are exported, mostly to the United States, Taylor said.
After his highway observation, Taylor, along with James Broom of the University of New Brunswick and Loïc D’Orangeville from Université Laval, began analyzing various causes that could have killed the trees, including pests and climate data.
New Brunswick had a drought in 2017 with warm, dry days in the summer and a hot fall, and their analysis showed that balsam fir is particularly susceptible to drought and high temperature. "This dry, warm growing season the year before, significantly stressed out these trees and led to their demise the year after, in 2018," Taylor said.
The team also looked at historical data and found a similar weather event in 1986 when balsam firs had died because of drought and heat the previous year. "It further reaffirmed our study ... that climate was indeed driving this mortality that we saw."
Fred Somerville, president of the Canadian Christmas Trees Association, said balsam fir is one of the most popular trees for Christmas, the others being Scotch and white pines and Fraser fir. Balsam fir, he said, likes cold winters and warm, damp summers.
Somerville, who has a farm in Alliston, Ont., about 90 kilometres north of Toronto, said climate change is making weather unpredictable. "As of now it's not the heat so much, it's the lack of rainfall that would hurt us," he said. "Over the last decade, I would say we've had several dry years, drier than we would like to see. But the last two years have been not too bad."
A lack of rain kills young trees or even newly planted saplings, Somerville said. Growth of older trees is stunted when they don't get enough rain, and they lack that bright green sought after at Christmas, he said.Â
Matt Wright, a Christmas tree farmer who manages M. Wright Farm and Forest Ltd. in Nova Scotia, said climate change and heat are affecting most conifers, including balsam fir. "The roots are struggling because of the heat," he said, adding that new pests are emerging that attack the trees.
"Climate change has pushed a change in the population dynamics of certain insects, especially those that overwinter in the soil, because we're not getting the deep frost or the cold temperatures that regulated when they could emerge or even survive," Wright said.
Taylor said heat and drought have weakened balsam firs, making them more vulnerable to pests and diseases that they would otherwise be able to defend against. More research needs to be done to understand how climate change will affect pests and Christmas trees, he added.
Some of the ways to mitigate effects of climate change are planting different species to improve resilience of forests and monitoring weather patterns, he said.
Last year was one of the warmest on record and 2024 is expected to surpass that, he said. While the 2018 balsam fir die-off is rare, it is likely to become more common with a warming climate, he added.
"The balsam fir Christmas trees that we all love, you know, unless we do something about climate change, we're going to have a lot less of them in 25 to 50 years," Taylor said. "If we continue down this path that we're on now, by the end of the century, there will be very few balsam fir trees left."
This report by °µÍø½ûÇø was first published Dec. 8, 2024.
