Dead ash trees may be restored

17_ash-7880DEAD ASH  — This dead Ash tree is just one of many that are around town which may be resurrected by culturing ‘stump sprouts.’  I-O Photo by Buck Traxler




Special to the I-O by Peter Kolb, MSU Extension Forestry Specialist

A lot of green ash trees were severely frozen back during last fall’s unusual cold spell.

Some people are removing these trees, roots and all and replanting green ash, all at an enormous cost.

Another potential way of dealing with this issue is by culturing “stump sprouts.”

Green ash is a commonly planted urban and yard shade tree in Montana. It grows relatively fast, is easy to produce in nurseries making it less expensive than some other shade trees and is relatively tolerant of poor soils, drought, insects, disease and cold.

It is native in eastern Montana in draws that have slightly better water supply than uplands. The other feature of green ash is its remarkable ability to re-sprout from damaged limbs, partially killed trunks, and the stump.

This has allowed it to persist  even though freak warm and cold snaps (or in Montana – normal 50 degree temperature fluctuations) often kill back large portions of the tree, much like poor pruning practices we often see under utility lines.

Although green ash can re-sprout into something resembling a tree, the larger the magnitude of damage to the original tree the greater the chance for growth with a high risk of large branch failure resulting in property damage and personal injury risk.

Due to a remarkable ability to re-sprout following injury; a technique called “stump culture” can be employed.

A green ash with a severely injured top still has a very strong and healthy root system in the first year following injury.

These trees typically store significant excess carbohydrates in their root system that allows the tree to rapidly re-grow leaves and branches.

The healthier the tree immediately before injury, the more stored energy it has. Thus, people wishing to help their trees recover, and faced with extensive damage to the above ground portion of the tree can help it re-grow from the stump.

The technique involves cutting the entire tree down and leaving a stump about three inches above the soil surface.

The cutting is best done in the early spring before the tree has leafed out but can also be done anytime the tree is dormant (fall-winter).

The tree will respond by producing multiple stump sprouts the first year. At this stage it is best to leave all the sprouts until the fall.

The resulting leaf area can produce energy to keep the root system alive. In the fall – winter or early spring of the following year, the largest and dominate stump sprout is left and the others pruned off.

When the tree breaks dormancy the second year the root system will put all its energy into this remaining sprout and it will grow 3-5 feet

By taking advantage of the existing green ash root system, a full sized ash tree can be re-grown in half the time it takes a newly planted ash to grow.

If you have questions or would like more information, contact Dan Picard, MSU Pondera County Extension Agent, in the courthouse or at 271-4054.