Walktober Month and Concern for Maple Tree Autumn Foliage
“Trees, our largest and most long-lived plants, shut down food production in preparation for the winter drought. But the hardwoods don’t quietly sulk into dormancy like skunks and groundhogs; they flare in a brilliant flash of color praised by poets and bus tour guides. New England’s fall foliage display is particularly bright, primarily due to the millions of sugar maples that paint the hills orange, yellow and red.” From New England Nature Watch: A month-by-month guide to the natural world around us by Tom Long.
Today is October 1st and even though The Last Green Valley (TLGV) annual program Walktober started two weeks ago, for many folks it’s October, the most glorious month of the year, that means Walktober is here. This year marks the 33rd year of Walktober in The Last Green Valley National Heritage Corridor and there are 280 unique opportunities to experience the natural and cultural wonders of one of the nation’s oldest National Heritage Corridors. Thanks to the creative efforts of 120 partner organizations, members and volunteers, exceptional adventures await you, your friends and family.
If you don’t have your Walktober guide yet, contact TLGV at 860-774-3300, and we’ll send you one, or better yet, check out the event listings on the TLGV website. You can find it at: https://thelastgreenvalley.org/explore/walktober/
This is the month of magnificent foliage as the leaves of our deciduous trees, especially the maples, turn ablaze of color. The quote from Tom Long at the start of this column is followed by this passage describing the process of leaves turning from green to multicolored foliage.
“Cool October nights stimulate cells at the base of each leaf to choke off the supply of water in preparation for winter, when the ground is frozen and water is difficult to absorb. This shuts down the production of chlorophyll, the green pigment in the leaves, and allows xanthophyll, carotene, and anthocyanin pigments to predominate for a few days before the leaves dry out and fall to the ground. Anthocyanin is the pigment that makes morning glories blue. Carotene makes carrots orange, and xanthophyll makes egg yokes yellow. Since production of these pigments depends on light, the leaves of the sugar maple might turn yellow in the shade and red in the sun. If early October is cloudy, leaves go from green to yellow. Sunny days and cool, clear nights generate reds, oranges and purples and paint the hills with color.”
I am afraid that this October we may not see the brilliant colors of our maples. Back in September I attended the Woodstock Fair and helped at both the TLGV information booth and the Eastern Connecticut Forest Landowners Association (ECFLA) information booth in the Agriculture Exhibits Building. I lost count of how many people asked us about the maple leaves drying up and dropping off their trees. I had noticed this condition with the large sugar maples on our property in Putnam. I checked in with my friend, and ECFLA founder, Steve Broderick to get his read on what was causing this maple leaf condition. Steve is well known in our region for his expertise in forestry, and for several years was the UCONN Extension Education Forester.
In response he explained it was a fungal disease, maple leaf anthracnose, a condition that has actually been discovered throughout our region. Thankfully it is not usually fatal to the tree. Here is some helpful information from the University of Massachusetts Center for Food, Agriculture and the Environment.
All native and non-native maples commonly planted as woody ornamentals are susceptible to infection of maple anthracnose. These include sugar maple ( saccharum), red maple (A. rubrum), Norway maple (A. platanoides), silver maple (A. saccharinum) and Japanese maple (A. palmatum).
ple anthracnose is often a minor disease that only reduces the aesthetic value of infected trees. Under ideal environmental conditions, the disease can be more serious, leading to premature defoliation and contributing to the decline of stressed and weakened trees. Healthy trees that are defoliated early in the growing season are often able to flush a new set of foliage and recover. Young trees that are recently transplanted are more susceptible to lasting damage while older, established trees typically suffer only minor growth losses.
Symptoms can vary by host and fungal pathogen present, but in general the symptoms are characterized by dark-colored, irregularly-shaped, angular spots or blotches that occur primarily along the midrib, primary veins and leaf margins. Lesions on Norway maple tend to be narrow, purplish-black streaks along leaf veins. On sugar maple, lesions occur along primary veins and appear as large, brown blotches. On Japanese maple, lesions occur along primary veins and leaf margins and the lesions can appear both tan or black in color.
Anthracnose fungi overwinter within leaf tissue and in infected twigs and buds. In the spring, fruiting bodies are produced and spores are spread by wind and splashing rainwater. Anthracnose fungi form within leaf spots and blotches and can be found on the upper or lower leaf surface and along veins or midribs.
Spores are produced whenever environmental conditions allow (mild and wet) from spring through late-summer, but are typically most abundant in late spring and early summer. Many anthracnose fungi have limited activity during mid-summer, when conditions are often drier and hotter. Symptoms on twigs and buds are less common on maples but under high disease pressure, tender shoots may be killed.
It is apparent that the rainy spring and summer has initiated the maple anthracnose that we are seeing impact the leaves of our region’s maples, and likely will impact the colorful fall foliage from our beautiful sugar and red maples. If you’re interested in learning more about maple leaf anthracnose you can find the May 2023 UMASS factsheet written by Nicholas J. Brazee at: https://ag.umass.edu/landscape/fact-sheets/maple-anthracnose
Despite the concern with maple leaf anthracnose and the possibly diminished colorful foliage of October, I for one will still enjoy the glorious month of October. If we’re disappointed in the color of the maples, just remember to look for the brilliant yellow color of our hickory and birch foliage. Oak leaves turn color later in the fall, and their muted shades of brown, tan and red are a welcome sight before the onset of winter.
October is here. I hope to see you at one or more of our Walktober walks, hikes, paddles, programs and events. This month brings countless ways to enjoy our beautiful region. I hope you’ll join me to care for, enjoy, and pass on this place we call home – The Last Green Valley.
Bill Reid is the Chief Ranger of The Last Green Valley National Heritage Corridor. He can be reached at email@example.com or by calling 860-774-3300.
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