Unless trees are wondrously furtive, I’m pretty sure they can’t migrate. Yet a report from the US Forest Service’s Northern Research Station indicates that 70% of Eastern tree species have already begun to shift their ranges to the north.
The authors admit this is not a new trend, but rather the hastening of an old one, saying:
“Fossil plant and pollen records show tree species’ ranges shifted northward a rate of 50 km per century as temperatures rose after the retreat of the North American ice cap. Such shifts are sometimes called ‘tree migration,’ but the more accurate term is ‘tree range migration.’”
Ma Nature apparently moved tree species an average of 50 kilometres every hundred years. This helps put in perspective a study report entitled “Shifting with climate? Evidence for recent changes in tree species distribution at high latitudes,” published in the journal Ecosphere in July 2014.
The study, conducted by Laura Boisvert-Marsh, Catherine Périé and Sylvie de Blois, examined 11 tree species common to eastern North America: Balsam Fir, Red Maple, Sugar Maple, Yellow Birch, Paper Birch, American Beech, Hop-Hornbeam, White Spruce, Black Spruce, Trembling Aspen, and Eastern White Cedar. Specifically, they looked at range alterations between 1970 and 2014.
I admit that this is a highly technical paper, and I may have pulled a muscle trying to understand it all. The study assessed changes at several different latitude points, and also compared sapling redistribution with that of larger trees. In addition, the authors noted that factors other than climate change no doubt had an effect on tree range migration as well.
However, their report concluded “Five of the eleven species examined (Sugar Maple, Red Maple, Paper Birch, American Beech, and Trembling Aspen) showed significant northward migration.” What stood out to me was that taken as a whole, they found “The average overall [range] shift was 111.2 km at 49° North [between 1970 and 2014].” Contrast that with historical movement of 50 km a century.
Scientists at the US Forest Service believe that by 2100, sugar maple will exist exclusively in Canada except for isolated “climate refugia” in the Adirondack Mountains and similar terrain. These micro-habitat refugia resist change, but are not immune to it.
Change is sometimes good, but it’s always scary. Luckily, we have agency in determining our future. According to the Canadian Association for Educational Resources, “By 2100 the atmospheric CO 2 concentration will be between 540 and 970 ppm.” The discrepancy between those values offers us a chance to slow the rate at which tree species march northward.
It’s hard to feel motivated when we know our decisions are a drop in the pool. Well, it takes something like 50 billion drops to fill an Olympic-size pool. If each Earthling coughed up (figuratively, please) 6.4 drops, it would be full. Everyone has access to a “dropper” of some sort. Planting a diversity of trees, especially drought-resistant species, will make it less likely the next generation will ask “Hey Grandma tell me that story again about when maples grew here.”
Read more about trees in New York State.
Photo of Sugar Maple courtesy Wikimedia user Bruce Marlin.