Abstract

FEUCHT, J.R. 1986. Wire baskets can be slow killers of trees. Am. Nurseryman 163(6):156-159.

Few argue with the fact that wire wrapped around the trunk of a tree will eventually strangle it. Yet wire that wholly or partially restricts roots does not seem to concern many landscape architects, landscape contractors and nurserymen. Indeed, planting specifications often require that the wire mesh be left on. The reasoning behind this seems sound; it is thought that the wire will soon break down, and the large mesh of modern tree baskets won't interfere with growth. Unfortunately, human logic and actual results are two different things. Wire mesh buried in soil for more than 15 years has been found to remain strong enough to cause root restriction, even thought it is corroded. In heavy clay soils that are low in oxygen, wire may not show the slightest corrosion even after years of burial. Wire in better aerated soils, such as sandy loams, will corrode, but it will remain a barrier to root expansion for a decade or more. As a root enlarges, it does not pull away from a wire, nor does it push the wire out of the way. It will enclose the wire the same way a limb or trunk will enclose a barbed wire fence that has been nailed to it. Once the root tissue grows over the wire and the edges meet on the other side, union of the tissues cannot occur because there is no cambial contact. Thus the vascular system of such roots becomes partially restricted. While partial restriction may not seem to be a problem in small roots, the real injury occurs when the surface scaffold or main brace roots (the root flare) become restricted. Avoiding the problem of partial root restriction is easy. Angle-bladed bolt cutters should be used to remove the wire completely from the top 10 to 1 2 inches of the ball. The cutting is best done after the tree is placed in the planting pit and partial backfilling has stabilized the ball.

• Copyright © 1986, International Society of Arboriculture. All rights reserved.