Why Does El Nino Affect Ontario's Fall Foliage?

Why does El Nino affect Ontario’s fall foliage? Trees respond to changes in daylight and temperature as autumn arrives. Green leaves get their colour from chlorophyll which helps trees carry out photosynthesis. As winter approaches trees pull nutrients back from their leaves and chlorophyll breaks down. This allows yellow and orange pigments to become visible. Red and purple colours come from anthocyanins which can also help protect leaves from sunlight. Cooler nights and bright days usually create the strongest display. With a warmer El Nino pattern this year those cooler nights may arrive later. Susan Dudley said that could mean slightly duller reds in some areas because trees may not need to produce as much anthocyanin.

Could Ontario Still See Spectacular Fall Colours?

Could Ontario still get a spectacular fall colour season? Experts say yes and several conditions are working in the trees’ favour. Last year some areas saw weaker colours after limited rainfall and hotter summer weather left trees stressed. This year trees across parts of Ontario have generally received enough summer moisture and have not experienced the same level of stress. Phillips said the warmer weather could even make leaf watching more comfortable because people will not have to deal with very cold conditions while visiting parks and forests. Ontario also has a strong mix of maple trees and other woody plants that create the bright red orange and yellow landscape that attracts visitors every autumn.

Where Will Ontario's Fall Colours Appear First?

So where should people expect the fall colours first? The season normally moves through Ontario in stages. Northern areas change first before the colour wave moves toward Muskoka and then central Ontario and the Greater Toronto Area. Algonquin Provincial Park is already showing strong colour with sugar maple and red maple trees displaying some of the season’s best foliage at the canopy level. The normal Ontario fall colour window runs from about mid September to late October. This year Phillips said the overall progression could be pushed back by several weeks because of the warmer El Nino pattern. That means anyone planning a fall trip may need to adjust the timing of their visit.

Will Super El Nino Change Ontario's Autumn?

Will the Super El Nino completely change Ontario’s autumn? That does not appear to be the expectation. The bigger impact may simply be a later and possibly slightly less intense colour change in some locations. Another factor could actually help the trees. Phillips noted that Atlantic hurricane activity has been significantly lower this year. Hurricane remnants can bring heavy rain strong winds and cloudy conditions that cause leaves to fall early or turn brown before reaching their brightest colours. Ontario therefore still has a good chance of getting the autumn display people look forward to every year with a message that wait a little longer and the reds oranges and yellows should still arrive.