Get Growing: Suffering sycamores

  • Remember how much it rained this spring? Those conditions brought in a bumper crop of Apiognomonia veneta, resulting in widespread infection of new shoots and leaves of sycamore trees. According to UMass, even mild bouts of wet weather can trigger spikes of infection. Macko Flower—Getty Images/iStockphoto

  • epantha—Getty Images/iStockphoto epantha—Getty Images/iStockphoto

For the Gazette
Published: 7/12/2019 3:35:35 PM
Modified: 7/12/2019 3:35:21 PM

This time of year I spend a lot of time staring at the American sycamore tree behind our house. This is because the tree’s upper branches are a favorite landing spot for Baltimore orioles. Those spectacular orange-and-black birds don’t show up very often, so most of the time I squint my eyes trying to turn rusty-breasted robins into their brighter cousins. But even without birds, the sycamore is a lovely tree to behold.

The American sycamore (Platanus occidentalis) grows throughout the eastern half of the country. It does well in lots of places, including cities, where it’s impervious to pollution, compacted soil and poor drainage. It is easy to identify because of its mottled, peeling bark in shades of tan, gray and greenish-white. Other distinctive features are its irregular branching patterns and its wide leaves that can be as big as dinner plates. American sycamores can grow as tall as 160 feet and 6 feet in diameter. George Washington recorded in his journal in 1770 finding a sycamore in Point Pleasant, Virginia, that measured 44 feet 10 inches in circumference at 3 feet from the ground. The trunks of large sycamores are often hollow and have provided shelter to early settlers and modern-day hikers and everyone in between.

Sycamores are majestic, long-lived trees that have significance in many cultures throughout history. The name of the tree comes from the Greek word sukomoras, which is a native Mediterranean fig tree.

According to legend, Hippocrates taught students medicine under the leafy canopy of a sycamore tree on the Island of Cos. The ancient Egyptians believed that the sycamore tree connected the worlds of the living and the dead. Two sycamores were said to stand at the eastern gate of heaven, releasing the sun each morning. Native Americans called sycamores “ghost trees” because of their pale bark.

In some years, I have noticed that our sycamore, along with others in the neighborhood, seems to leaf out later than other deciduous trees. But eventually, by mid-June, it looks fine and I stop worrying about it. This spring when I visited Washington Square Park in New York City, the head gardener mentioned that the sycamores in the park are suffering from anthracnose. As I inspected the trees, I observed that they looked the same the sycamores in Amherst. Their leafing-out patterns were uneven; some leaf clusters looked normal and healthy, while others remained unfurled as if they’d been killed by a hard frost.

The gardener said that anthracnose is an increasing problem and that the park is gradually replacing its aging sycamores with London planetrees, which are more resistant to anthracnose.

When I got home, I went online and found a bulletin from the UMass Extension service about anthracnose. There’s bad news and not-so-bad news.

Anthracnose is caused by a fungal pathogen called Apiognomonia veneta. This fungus flourishes in wet weather. Remember how much it rained this spring? Those conditions brought in a bumper crop of Apiognomonia veneta, resulting in massive spore dispersal and widespread infection of new shoots and leaves of sycamore trees. According to UMass, even mild bouts of wet weather can trigger spikes of infection. Symptoms include blotches on leaves and cankers on twigs and stems. The irregular branching pattern commonly seen in American sycamores is caused by repeated bouts of anthracnose. When a terminal bud on a branch is infected, the lateral buds sprout, sending out shoots at right angles to the branch.

According to the website “Folklore of the sycamore tree by Mae Clair,” the Native American Wyandotte tribe has another explanation for the irregular branches of the sycamore. Wyandotte legend has it that the great chief who ruled over evil spirits grew angry at two of his followers and cast them down to the earth. There they crashed into two stately sycamores on a riverbank. The wicked nature of the spirits seeped into the trees and immediately deformed them, turning their limbs into twisted, grotesque branches.

Fortunately, anthracnose does not usually cause lasting damage or death. As drier weather comes in early summer, the trees are able to produce new leaves and by late summer they regain a normal leaf canopy. My daily inspection of our backyard sycamore has confirmed that new leaves are opening. Unfortunately, climate change has made colder, rainier springs a regular occurrence in the northeast. So we have lots of anthracnoses to look forward to.

Steps to mitigate the problem include thinning branches to increase air circulation and sunlight so that leaves dry more quickly. The fungus overwinters in diseased branches and twigs and in fallen leaves. Raking dead leaves and pruning infected wood will help decrease infection. But obviously, pruning is not an option with large, mature trees.

In areas where sycamore anthracnose is severe, it is recommended that London planetrees and Oriental planetrees be planted to replace them. I will certainly keep that in mind for the future. In the meantime, however, I am enjoying watching the mid-summer leaves of the sycamore unfurl. Better late than never!

Mickey Rathbun, an Amherst-based lawyer turned journalist, has written the Get Growing column since 2016.

Upcoming garden events

Old Growth Treeson Mount Tom

It may surprise you to learn that there are still some old growth trees in our region. Kestrel Trust has planned a guided walk on July 13, from 10 a.m. to 1 p.m. with Bob Leverett, educator, author, and old growth tree expert, on Mount Tom. Leverett will identify individual tree species growing along the trail, discuss how he measures trees for championship competitions and point out several of Mount Tom’s superlative trees. You’ll also learn about where the woodlands of Mount Tom fit in with carbon sequestration and the impact of climate change. Come and enjoy these majestic trees. They contribute greatly to our natural and cultural wellbeing. Free, but registration is required online. Go to: kestreltrust.org for more information and to register.

Celebrating ourlocal farmers

On Aug. 1, Kestrel Land Trust and CISA (Community Involved in Sustaining Agriculture) invite you to a special farm-to-table dinner to celebrate farmers and the land that sustains us all. The dinner will take place at Red Fire Farm in Granby from 5:30 to 8 p.m. There will be an informal farm tour at 4:45 p.m. Enjoy a delicious summer meal with friends outdoors next to Red Fire’s fields. Dinner will be prepared by the Wheelhouse catering team, who excel at bringing locally grown food to the table for a memorable culinary experience. Cost is $75 per person. Proceeds benefit Kestrel and CISA. RSVP required online. Go to: kestreltrust.org.

Wild Edibles

On July 18, from 9 a.m. to noon, Tower Hill Botanic Garden in Boylston will host an indoor/outdoor program about the edible qualities of many of the wild plants growing in our midst. Worcester County is home to over 100 species of edible wild plants, some of which are more nutritious and/or flavorful than their cultivated counterparts. While some of the less common edible native species must be harvested sparingly (if at all) to minimize any adverse ecological impacts, common native species, as well as the plentiful edible weeds and invasive species, offer more care-free foraging opportunities. Russ Cohen, expert forager will lead the program, which will start with a slide show featuring many of the tastiest wild plant and mushroom species the region has to offer. This will be followed by a walk in a wilder section of Tower Hill, where the group will encounter up to two dozen species of edible wild plants (and, pending favorable weather conditions, mushrooms). Keys to the identification of each species will be provided, along with information on edible portion(s), season(s) of availability and preparation methods, as well as guidelines for safe and environmentally responsible foraging. Russ will also provide handouts as well as a foraged goodie or two for people to taste.

Russ Cohen, a naturalist and wild foods enthusiast, has been leading edible wild plant walks and talks for over 40 years. Russ’ foraging book, Wild Plants I Have Known... and Eaten came out in June of 2004 and is now in its seventh printing.

Members: $39/nonmembers: $53. For more information and to register, go to towerhillbg.org.




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