October 2008
Featured Articles

How to Keep Your Trees in a Storm

By Jerry A. Chenault

“How to keep your trees in a storm” seems like an unusual topic for a guy who lives on a farm in Lawrence County with almost no trees left after the tornado of February 6. Yet, the hurricanes of recent years are yielding data for those who study environmental horticulture … and there are some things we can learn from their data. Let’s take a gander, shall we?

    Tree Huggers
There are a couple of “real tree huggers” (a live oak embracing a neighboring pine) at the Mobile Botanical Gardens.
   

For starters, some trees most definitely hold up better against extreme winds than do others. Here’s a list of some of those: flowering dogwood, American holly, Foster holly, yaupon holly, crape myrtle, Southern magnolia and bald cypress. Why do these trees make it when others are shredded? They tell us cone-shaped trees fare better in storms and so do trees having a dominant trunk and smaller branches. And small, mature size is also a factor in their favor.

Some other factors influencing tree damage by storms include site design and management practices (like proper planting and pruning). Site design includes making sure the tree has adequate soil area for its roots. Unlike those trees planted in the narrow medians at shopping malls or street trees wedged between the street curb and a sidewalk. If roots are cut or damaged by construction, well, you can guess how that factors in as well.

And speaking of cutting roots, when a new home is built (or street, garage, underground irrigation lines, etc.), trees suffer either from root cutting, soil compaction or maybe oxygen depletion by asphalt or concrete. Either way, there is root loss. Then we make it even worse by mounding soil up over the roots. That chokes a tree slowly to death. It may take 10 years, but death is often the outcome.

The addition of mulch piled up around the root ball and tree trunk also hurts the tree as bad as cigarettes hurt humans! Cutting edge research shows we should have no more than a one-inch depth of mulch covering the tree’s root ball. Other areas can have up to three inches of mulch, but be sure not to pile mulch up on the tree trunk! That’s new information and it has been confirmed many times in research at the University of Florida by Dr. Ed Gilman. It is a proven fact.

A few other trees that do fairly well in storms are: Japanese maple, river birch, ironwood, redbud, common persimmon, white ash, sweetgum, sweetbay magnolia and saucer magnolia. Sycamore,  winged elm and Osage orange do fairly well too. But watch Osage orange for flying fruit! Like cannon balls!

The S.T.A.R. team project of the Urban Affairs division of the Alabama Cooperative Extension System wants you to know how to properly care for your trees because they are such an important factor in having a healthy, happy life. They cool our homes, protect from winds, purify our air, and help to calm and de-stress us in a hectic world of metal and concrete. That’s why S.T.A.R. team projects focus on greenspace development, on Tree City USA projects, on faith garden projects and nature-based outdoor activities. Trees are so important to us in ways we are only beginning to understand. Let’s keep them, shall we?

Jerry A. Chenault is the Urban R.E.A., New & Nontraditional Programs with the Alabama Cooperative Extension System.