Tree Death Due to Strangulation: Trunk Girdling due to nylon twine

Curtis E. Swift, Ph.D., Colorado State University Extension

Dying Spruce A housecall in mid summer 1997 was requested to determine the reason for the sudden collapse of a Colorado Blue Spruce Picea pungens. According to the owner, the tree had suddenly taken on a purplish-red cast and died.

The tree was planted in 1990.

The sudden collapse of the tree and color change of needles was indicative of root or lower trunk injury.

It is not uncommon for trees planted with chicken wire around the root ball to respond in this manner. Chicken wire is still used to help hold root balls of trees together. If the wire is not removed, roots emerging from the root ball may be girdled and the tree experience a sudden collapse. This often takes place five to ten years after planting. In recent years, however, wire baskets with larger spacing between the wire has been used in place of chicken wire. As with chicken wire, the wire basket does not decompose and can create a root hazard. Due to the similarity of the problem with `chicken wire syndrome', it was recommended the tree be dug and roots checked for problems.

wire basket around root ball

When the tree was dug, the first thing noted was the presence of the wire basket remaining around the original root ball. Some of the roots extending from the root ball had suffered damage from the presence of the wire, but not sufficiently to cause the total collapse of the tree. If the tree had survived, however, this root damage would have caused future branch death.

nylon twine girdling trunk

Further examination of the root ball indicated the presence of nylon twine used to hold the basket on the tree. The twine extended around the trunk of the tree.

It took seven years for this tree to die. The sudden collapse and death of the tree was due to a contractor neglecting to remove the nylon and girdling (strangulation) of the tree resulted.

Recommendations:

  • Always remove twine from the root ball and around the base of the tree when planting.
  • Always cut away and remove the upper 9 inches of the wire basket after setting the tree in the planting hole. As noted in the first photograph, roots typically develop from the upper inches of the root ball. These are the roots needing protection from the girdling effect of wire baskets. Removing the lower portion of the wire basket is not necessary and may result in damage to the root ball resulting in tree death.
  • Hire contractors with adequate experience and knowledge to avoid such damage. This might require you, as a consumer, asking detailed planting questions of the contractor.
  • Hold the contractor liable for faulty planting resulting in tree death. If your tree died due to such negligence, it is highly likely other consumers have also suffered plant loss due to similar planting negligence by the same contractor. A tree appraisal to determine the value of the tree is strongly recommended.

References:
Feucht, J.R. 1986. Wire baskets can be slow killers of trees. Am. Nurseryman 163(6):156-159
Harris, R.W. 1992. Arboriculture: integrated management of landscape trees, shrubs, and vines - Second Edition, Prentice Hall. Page 208
Lumis, G.P. August, 1990. Wire Baskets: research sheds new light on the wire-basket controversy. American Nurseryman.
RMLP Revisits the Wire Basket Tug o' War. September 1992. Rocky Mountain Landscape Plus.
Watson, G.W. and E.B. Himelick. 1997. Principles and Practice of Planting Trees and Shrubs. International Society of Arboriculture. Page 109.