September 30, 2004 at 9:18 a.m.
The U of M is getting many calls from homeowners asking––What’s wrong with my maple tree? Their concern, that they are beginning to turn color much too early. I always felt that early maple fall coloration means that the tree is stressed. Patrick Weicherding, Regional Extension Educator, wrote an interesting article on the subject.
The symptoms are early fall coloration, reduced foliage growth, reduced twig growth, dead branches in the upper canopy and even the death of the tree. The problem appears to affect sugar and red maples, appearing less in Norway maples.
Longtime USDA Forest Service researcher, Dave Houston, coined the term “maple decline,” describing the problem. He states the problem is a progressive disease condition that begins when the trees are initially altered by stress, and continues with the decline of the tree’s health.
The maple decline is not a new phenomenon. As early as 1917 in Massachusetts forests, the dieback was attributed to drought. What is new is that today maple decline is much more prevalent in urban areas where maple trees struggle to remain healthy in the sometimes harsh city conditions they are planted in.
How do you know if your tree is suffering from maple decline? One of the symptoms is reduced twig growth. Yearly twig growth varies considerably between trees and even within the canopies of individual trees. If the distance from bud scar to bud scar is less than or equal to five inches on a non-shaded twig, the tree may be in trouble.
Keep in mind the normal, healthy appearance of the particular maple foliage. Foliage that is sparse, light green and/or marginally scorched signals that the tree may be declining. Maples normally begin showing fall color after the first frost or in mid-to-late September. When fall colors develop earlier than normal, in late July or early August, the maple is suffering from decline.
Small dead branches seen in tree tops in late spring or early summer are also indicative of decline. Over time, larger more visible branches and limbs will die back. The more numerous the dead twigs or branches are, the more severe the decline condition.
If roots can be examined, look to see if the roots are “stem girdling.” Also, look for reduced occurrence of smaller, fibrous roots at the drip line of the tree crown. Brittle roots, decaying roots, are indicators of root decline, which severely affect the root and shoot ratio of the tree. A well balanced root/shoot rate is necessary for the good health of the tree.
I hate to be the bearer of bad news. However, by the time you notice the symptoms, the tree is probably beyond help and can’t be restored to good health. So, this may be the time to think about replacing that declining maple. If you still want a maple in that spot, consider one of the cultivars that is more tolerant of urban conditions. You may not live in an urban community, but the trees in your yard are still exposed to salt and exhaust fumes.
A naturally occurring hybrid or cross of a red maple and silver maple, is known as a freeman maple and is a good urban tree. These hybrids have the beauty of a red maple, and the fast growth of the silver maple, without the problems of the silver maples and the pH sensitivity of the red maple. One of the best cultivars for Minnesota is Autumn Blaze, others that are also available include Red Sunset and October Glory.
Remember, the Norway maple is not as prone to maple decline, but the leaves only turn yellow in fall, and lack the vibrant fall colors we want maples for. But on the plus side, it is a fast growing tree that holds its leaves well into late fall.
There are three remote drop off sites for samples in the county: Mannions Greenhouse and Floral in Rush City, North Branch Floral and Federated Coop (Cenex) on Highway 8 in Chisago City. There will not be a Master Gardener on site, but these businesses have agreed to hold the samples for pickup.
There will be Master Gardeners on site to answer your questions Thursday evenings from 6-8 p.m. at the Chisago County Hazardous Waste facility in North Branch.
The Lindstrom Farmers Market is now open. There is a Master Gardener there from 8 a.m.-noon every Saturday.
Other ways to access information:
Check out the “Hot Topics” box in the middle of the page for current Chisago County Master Gardener news and events. You can also click on “Ask a Master Gardener” next to the cute little flower on the right hand side of the page. Here you can search 1000s of answers from Master Gardeners around the state. If you don’t find your answer, you can submit a question online or search for University publications.
Bell Museum of Natural History
For information about snakes, skunks, raccoons or other wildlife around your yard, call the wildlife information line at (612) 624-1374 or www.bellmuseum.org.
Master Gardener voice mail: 651-237-3080
Leave a message and a Master Gardener will call you back within a couple of days.
Master Gardeners will be moving to the “Anderson Chiropractic” building in North Branch soon. A fixed lease for three years was approved by the County Board. Extension Services are also relocating to this site, by the Lake State Credit Union building.
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