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Ask the Ecologist:

by Belle Bergner
maple

Q: My maple tree looks like it is dying because some of the branches are dead at the ends. Is this something that will be gone next year and my tree will recover, or will it cause my tree to die? – Robin Leenhouts, Riverwest Resident

A: What you probably have is girdled roots, drought stress, or a combination of problems causing a nutrient deficiency.

If your tree has small leaves, death of small limbs, top dieback or leaf scorch, you probably have girdled roots. This happens when a root entwines around another large root or the base of the tree, or some other structure (such as sidewalk and pavement) prevents or reduces water and nutrient movement.

What to do? This can be difficult to fix in an urban setting – especially if the tree is surrounded by sidewalk or street asphalt – because you can’t remove the girdling root without removing the asphalt and/or sidewalk around it. Try watering the tree by letting a hose soak the ground slowly for a 10 minute period. Do this a few more times before the end of the growing season. In the winter, don’t use salt on your sidewalks – use sand or bird seed instead. Salt limits the ability of trees to uptake nutrients. If the tree appears to be worse next year, call an arborist to remove the tree before large limbs fall off and potentially cause serious damage.

If your tree is on the green strip between the sidewalk and street, tree maintenance is the responsibility of the City Forestry Department. An urban forester will come out and assess hazardous trees at no charge at 286-3595. If a tree has to be removed for safety reasons, you can request that another tree be planted in its place at no charge, and you can request a favorite species too.

If you think you have an insect or disease, contact the University of Wisconsin- Extension office at 414-290-2414. They will analyze leaf samples and tell you exactly what you have. Chemical control of diseases and insects on large trees is usually not feasible since adequate coverage of the foliage with a pesticide cannot be achieved. Don’t be misled by pesticide companies who claim that they can fix your problem with their magical potions.

For further information on pests on your yard, contact the University of Wisconsin- Extension office at 414-290- 2414.

Send your ecological inquiries to our resident ecologist at bergnerb@ gmail.com.

Riverwest Currents online edition – October, 2006