Multi-Stemmed Trees

A splitting multi-stemmed tree with a deep V-shape. Photo by Steve Houser.

Published January 28, 2008, By CHRIS BREWER

Many of our clients have one or more multi-stemmed trees on their property. These trees require more scrutiny than a single-stemmed tree.

There are three classifications of trees with more than one stem:

1. Single trees planted in close groups.
2. Trees which have grown from rootstock or from a tree stump.
3. Trees whose multiple stems begin just above ground level.

Trees in the first group compete with each other for all the things essential to healthy growth; water, sunlight, nutrients, and space to develop a root system. The competition to develop good structural roots causes problems when single trees are planted too close to one another. When one tree in the group dominates the other stems, the subordinate trees develop abbreviated root systems and coexist. Trees with partial root systems are prone to failure, normally falling away from the other trees in the group.

If an arborist or informed tree owner spots the potential risk, it can be lessened by installing support cables. If one or more stems fail, brace rods will be necessary to support the remaining stems.

The second group, rootstock growth or trees growing from a stump, is not suitable for suburban landscapes because of its inherent weakness. Rootstock growth are always weakly attached to each other at the ground and present a higher than average risk of failure. If an individual wishes to retain a mature rootstock tree, cabling and bracing may be used to deter failure.

Trees that fork above the ground may also be addressed with hardware. If the forks are in a tight “V” shape, they can more than likely benefit from cabling. If a tree has “U” shaped forks, these are much stronger unions and cabling is probably unnecessary.

Cables and brace rods are great supports for weak stem junctions, but do not guarantee that your tree will not fail. Any tree can fail under the right circumstances.

Multi-stemmed trees present special challenges which Arborilogical Services, Inc. is prepared to meet.