This year’s autumn leaves have been so spectacular that some drivers have stopped their cars in the middle of the road as they try to capture the moment on camera.
Though irritating and dangerous to come upon those drivers, it’s easy to understand their behaviour with all the golden maples and russet bronze oaks blazing with intensity this season.
Islanders who pay close attention to their surroundings and the natural environment have confirmed that it’s not just in our imaginations: the colours this year really are more intense. The reason has to do with the weather both over the summer and into the fall, with the 2017 combo just right to produce brilliant yellow and red leaves.
“I think it’s a particularly beautiful fall,” said artist Nicola Wheston last week. “What I notice about trees is they really have their glory times and they have cycles, and they have them in the spring and the fall.”
Richard Fraser takes a trip through the Fraser River Canyon every year in the fall for seed collecting, and confirmed that what he’s seen there is above average. It’s also true of the plants he grows on Salt Spring at Fraser’s Thimble Farms.He explained plant stress caused by weather and seasonal changes are the main factors in colour variety. In the Eastern provinces the drop in overnight temperatures is the significant player. On the West Coast, rainfall is more of a factor.
“Without the summer drought you don’t get good fall colours — and in the nursery this year it’s spectacular,” Fraser said. “You can see all the subtleties, the apricots, oranges and reds. You only really get that around once in 10 years.”
Photographer Michael Levy is another person who pays close attention to the island environment. Looking back at his archives, he said he’s noticed some correlating factors between years when he’s taken a lot of leaf colour shots.
“One is a long dry summer tends to lead to a good colour display, and I think that has to do with the stress,” Levy said. “And fall is also lasting later in the year this year, so the colours are extending over a longer period of time rather than just a week or two. The big leaf maples are going really late. A lot of times they’re very, very bright for a very short amount of time and then they just curl up and turn brown.”
The scientific reason for changing leaf colour is a biochemical process triggered by shorter periods of daylight and cooler temperatures. According to the USDA Forest Service, the two most significant factors on fall colour are moisture and temperature. Most of the year, chlorophyll production produces the green colour that overrides the other pigments present in leaf cells. Chlorophyll production slows and then stops as days shorten, allowing carotenoids (responsible for yellow, orange and brown) and anthocyanin (reds and purples) that are always present to become visible. Anthocyanin production can also increase in autumn in response to bright light and plant sugars.
For more on this story, see the Nov. 1, 2017 issue of the Driftwood newspaper, or subscribe online.