Thursday, October 3, 2013

Amy Ivy On The Fall Foliage Season

GFP_2053autumnbyway725The northeastern United States is one of the few locations in the world that develops intense fall color (along with northern areas of China, Korea and Japan) and our region is just hitting its stride.

With all the variations in colors and tree species, it can be difficult to determine when an area is truly at peak color. I’d encourage you to enjoy all the transitions as they occur and look for the spots of color and beauty throughout the fall months around the region.

There are many factors that influence fall color.  The yellow and orange pigments are always present in the leaves; they are just masked by the green chlorophyll until fall.  As the leaves begin to get ready to drop the green fades away, revealing the yellows and oranges. 

The red color that also contributes to the intensity of the purples and oranges is a result of accumulated sugars in the leaves that produce the red pigment, anthocyanin.  The amount of red in the leaves is directly related to the weather that occurs while the leaves are turning. The weather during the growing season has little if any effect on fall color.

The best conditions for producing the red color are just what we’ve been having a lot of lately: cool nights and sunny days.  Nina Bassuk, from the Urban Horticulture Institute at Cornell University explains it this way: “It is this combination of sunny days and cool night temperatures during the time when leaves change color that determines whether it will be a good or great year for fall color. Rainy, overcast, warm weather during this time will produce a display rich in yellows but poor in reds.”

Each species of tree turns its own distinct color.  For example, birches turn yellow as do Norway maples while sugar maples turn orange to orange-red and our native red maples turn scarlet.  Our native white ash trees turn beautiful shades of purple while the green ash, which is the type sold in nurseries, turns yellow.

When you shop for trees to add to your landscape, consider their fall color.  Many cultivars have been selected particularly for this.  The serviceberry ‘Autumn Sunset’ has pumpkin-orange fall color while ‘Cumulus’ has yellow to orange-scarlet color.  Within the red maples (not the red-leaved Norway maples like ‘Crimson King’) you can find many good choices.  ‘Autumn Flame’ has early, long lasting red leaves in fall while ‘Northwood’ has more of an orange-red color.

The different trees also turn color at different times.  Looking at our native trees, birches often start off with their yellow color while the red and sugar maples color reach their peak mid season with their oranges and reds.  Oaks and poplars are among the last to turn.  The oaks turn shades of bronze, purple and burgundy while the poplars turn a yellow-orange.  Some parts of the Adirondacks have stands of tamarack or larch which turn bright yellow in late fall.  Tamaracks look like spruce trees all summer then surprise you by turning color and dropping their needles.  They are the only deciduous conifer we have here.

The deep-colored oak leaves persist a long time after the leaves of other trees have fallen and look beautiful with a dusting of snow.  The tree with the longest lasting leaves of all is our native beech.  These golden copper leaves last through most of the winter and are a beautiful site along cross-country ski trails in the middle of winter.

Get out and enjoy the beauty of this fall season.

Photo courtesy George Fischer/Great Lakes Seaway Trail.

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Amy Ivy is a Regional Vegetable and Berry Specialist with Cornell Cooperative Extension and the Eastern New York Commercial Horticulture Program. Amy also often leads local foods production research funded by the Northern New York Agricultural Development Program. She can be reached at 518-570-5991, adi2@cornell.edu.




One Response

  1. Wally says:

    Very interesting article. There definitely are spots of color out there, as we saw on Moreau Lake while kayaking yesterday, even though green still predominates. I especially enjoy the bright red of Virginia creeper on tree trunks right now that stand out in contrast to the muted shades.