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Treat Your Shade Trees Right

If you’re not part of the solution, you’re part of the problem

Think again if you think shade trees pretty much care for themselves.
    In the forest, where trees care for themselves, fewer than one percent of seedlings grow to become marketable trees.
    What do you know about how the crotch angle, crossing branches and branch spacing affect tree health? Allowing narrow crotch angles on branches and stems to remain on young trees will result in premature tree damage. Rot is another common problem with narrow crotch angles. Branches that rub against each other result in early breakage. Young trees need to be trained to proper branch spacing.
    Nursery-grown trees raised in containers tend to develop girdling roots as they mature. Most girdling roots can be seen above ground or at the ground level. Look for roots circling or partially circling the trunk. Often the roots are embedded or being absorbed by the trunk. Cut such roots away with a sharp chisel or ax and remove them.  
    Parking your vehicles beneath the branches of the trees, do you consider the 800 to 1,500 pounds of pressure exerted by each tire? Ninety percent of trees roots can be found in the upper 10 feet of soil. The weight of cars and trucks compacts the soil, as do the tires of lawn mowers and the feet of people, including those who enjoy the shade of the branches during the summer.
    The roots of plants cannot grow in soil with 85 percent compaction or more. If you cannot poke a sharp dowel or digging shovel into the ground six inches or more, the soil is too compacted for roots to grow.
    Every year at this time, you rake away the leaves that fall to the ground. In the forest, fallen leaves return both organic matter and nutrients to the soil, hence to the tree.
    Nearly all fertilizer applied in the shade of branches is used by the turf. Very little nutrient from that fertilizer leaches down to the roots of the tree. Applying excessive amounts of fertilizer to satisfy the needs of the tree roots will result in fertilizer burn of the turf.
    Are you your shade trees’ friend or enemy?


Tree Help Needed

Q    In the spring I planted several fig trees. They  seem to be very slow growers and are now only maybe one foot high. I want them to live this winter. Any suggestions on what I should do?
    –C. Buchheister via email

A    If your fig trees are only a foot tall after growing for one year, your soil is deficient and poor. Your fig plants should be four to five feet tall at the end of the first growing season. Have your soil tested. With their limited root system, I doubt if the trees will survive the winter no matter what you do.

Q    Can you advise on how to eliminate the black soot or mold that is covering the leaves on my Nelly Stevens holly trees?
    –Lauren Avery, Millersville

A    The black on your Nelly Stevens holly is sooty-mold. I suspect your holly may be infested with scale insects. Inspect the undersides of the leaves and stems. The scale insects may be white or yellow-brown like small drops of wax. If your hollies are under maple or tulip poplar trees, it could be that the scale is feeding on the trees and the honeydew has drifted on the holly causing the sooty-mold to grow. Sooty-mold is best removed with a strong jet of water from a garden hose or power washer.


Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.