UpDate - Vol. 13, No. 38, Page 1
July 21, 1994
Towering trees removed to protect remaining elm stand

     Four of the stately American elm trees on the Mall had to be
removed this summer-the victims of Dutch elm disease.
     According to Roger Bowman, supervisor of Facilities Management's
grounds division, the 70-years-plus-old trees had a deceivingly
healthy appearance, and they had to be sacrificed to save the rest of
the stand since the disease can spread from tree to tree.
     Bowman and his crew of professional arborists-Michael Eggert,
John Heldorfer and assistant John Pierce-take aggressive steps to
protect campus elms from infection.
     Each year, approximately one-third of the elms are treated with a
preventative fungicide. Bowman said this course of action seems
effective and that few trees have had to be removed in the past
several years.
     To protect the healthy population from infection, diseased trees
must be taken down at a stage when they may appear to be healthier
than they are, he said. Removing a diseased tree when it still has
structural integrity also protects the safety of the arborists, who
must climb into a tree to cut off branches before it can be felled.
     When the diseased American elms are removed, they are replaced by
Village Green zelkovas, members of the elm family that are resistant
to Dutch elm disease. Bowman said the new zelkovas, once established,
grow 4-6 feet per year and resemble American elms very closely in size
and shape.
                                                    -Kathleen Therrien