A Featured Event:  Fall Foliage 

As we canoe camped in Killarney Provincial Park two weeks ago, we watched fall really begin as the colours began to change here and there, and leaves started to drop from the trees onto our campsite.  Still a long way to go, but a sign of more colours to come.

The colour shift is keyed by day length, rather than temperature or frost -- as the days grow shorter, the trees begin to pull nutrients back into the tree for storage over the winter, and the production of chlorophyll  (the green pigment that captures the suns energy) shuts down.  As the greens fade, reds, yellows and oranges that had been hiding there begin to show.  Carotenes give us the yellows and oranges, while anthocyanins provide the reds. Try this activity to witness the invisible colours right in the classroom.

Again, the intensity of the colour has more to do with sunlight than with temperature.  Colours will be more intense if there’s been a good growing season – plenty of water and sunlight.  Also, reds are more intense when fall sunshine allows the production of additional sugars and cool, but not freezing nights slow the enzyme activity that destroys the anthocyanin pigments. With a generally heavy spring snowpack (good) but a hot, dry summer (bad) and possibly plenty of fall sunshine (good), this year’s predictions are, well, up in the air.   Some leaves may also change early due to drought stress.

Colour can be quite variable, both within and among different species.  White Ash can vary from yellow to purple.  Male Red Maples  tend to be red and females yellow.  For oranges, look to Sugar Maples and Staghorn Sumac; for yellows, Silver Maple, Trembling Aspen and White Birch; for reds, Red Maple, Pin Cherry and oaks. There is some evidence that individual trees turn a similar colour each fall. Try your own observational experiment by noting the colours of trees nearby your home or school in a journal or painting and compare the colours in subsequent years.

Finally, a corky layer forms between the leaf and the tree, eventually weakening and detaching as the leaves fall and drift on the autumn winds. Eventually, the leaves find their way to forest floor, where although dead, they become part of an important cycle providing life by decomposing, providing food for numerous soil organisms, and putting nutrients back in the soil.  Some trees, however – oaks and beeches in particular – don’t form this corky layer and remain on the tree long into the winter and at times even the next spring.  These trees are termed marcescent.

Now, colours are at or slightly past their peak in Algonquin Provincial Park and the Haliburton Highlands. To find out the extent of colour in Ontario provincial parks, visit Ontario Parks Fall Colour Report. 

Other Happenings: 

• Many of the warblers that have been flitting about are now heading south.  Golden-crowned and Ruby-crowned Kinglets, however, are arriving in some numbers, along with Yellow-rumped Warblers, which are the last warblers to leave in the fall.
• Northern Canada Geese continue to over fly the area.
• Your backyard feeders may be busier now than at any other time of the year, as residents prepare for winter, and migrants fill up for their long trips.  Get out the guides and start identifying!
• In the forest the drumming of the male Ruffed Grouse, commonly heard during the spring mating season, returns as young males establish their own territories.
• Another sign of fall:  rustlings from the attic.  Deer Mice are looking for a secure winter nest, and often seek out buildings, woodpecker holes or even birdhouses.  Care should be taken when handling deer mice and their droppings, as they may have the Hantavirus, which can cause a serious infection in humans. Big Brown Bats may also be looking for wintering spots in older buildings. 
• Cluster flies may be abundant this year.  They are a bit larger than houseflies, and have fine, light hairs on their backs.  At this time of year they find cracks and crannies in buildings to over-winter in, but mild temperatures may not have driven them inside yet.  If they make it inside, they will buzz against south-facing windows on sunny days.  Unlike House Files, cluster flies are not interested in your food, do not develop in garbage, and are not a sign of unsanitary conditions.  They are just irritating!  They begin laying eggs in the soil in spring, and the larvae enter earthworms and develop inside.  Wet conditions during the spring may increase the earthworm population, and thus the fly population as well.  Everything is connected!!  The adults eat nectar and fruit.
• The combination of bright, sunny days and cooler air temperatures can lead to basking reptiles and amphibians on logs, rocks and road surfaces.  Frogs and toads are still abundant, and Eastern Garter Snakes are active.  They are the last snakes to make their way to winter shelter.
• Snowy Tree Crickets will continue calling until the first heavy frost.  This site has some fun with chirps!  Listen to warm and cold Snowy Tree Crickets here (scroll down).
• The full moon following the Harvest Moon (see Mid-September) is called the Hunter’s Moon, a time when hunters in both Europe and native North America could pursue their prey by the moon’s light.  It is associated with feast days in both locations.  This year, the Hunter’s Moon occurs on October 11^th.  We’re listing it now to give you time to prepare if you so wish.