June 13, 2001 | By: Laura Skillman

Black cherry trees grow in abundance across Kentucky's landscape. These trees are an important timber and wildlife species yet can cause cyanide poisoning in livestock.

The leaves of the trees, especially wilted ones, are high in cyanic acid, which can kill livestock by depriving them of oxygen.

Farmers commonly reduce their likelihood of livestock losses due to wild black cherry trees by cutting them out of fence rows. They may want to remove cherry trees that pose a risk, such as ones potentially losing branches or in poor condition. But those that do not pose a risk can be left to become a potential timber source.

If a farmer is going to take out a tree, it is important that it is done properly to reduce sprouting and recurrence of the trees, said Jeff Stringer, University of Kentucky Extension forestry specialist.

These trees have a propensity to sprout from the cut stump and can also sprout from the roots, so extra precautions are needed. Also, fence rows should be checked for the inevitable re-establishment of cherry trees from seed carried by birds, he said.

The quickest way to reduce or eliminate sprouting is to properly use herbicides that are labeled for controlling black cherry in pasture or fence rows. These herbicides are systemic, meaning they will travel throughout the plant and have the potential to kill all or a portion of the root system so that sprouting is reduced or eliminated.

If herbicides are not used, sprouting can be expected and several cuttings will be required until the food supply to the roots is exhausted, Stringer said. This could take several years.

Herbicides can be applied in one of two methods, foliar spray or "cut stump" applications.

A foliar spray can be used if the trees are small enough to allow coverage of all, or a large majority of, the leaves with the spray. This technique involves spraying a diluted concentration of herbicide to cover the foliage.

Many herbicides are labeled for foliage application of brush and trees. Foliar applications work best after trees have fully leaved out until one or two weeks prior to leaf fall. The treated tree should remain in place until all the foliage has browned, ensuring that the herbicide has entered the root system.

Check product labels for restrictions on pasturing and entry into treated areas. Generally, livestock should not be allowed access to areas where trees have been sprayed until the trees have been removed or wilting foliage is no longer present.

Larger trees should be cut down and then a herbicide treatment applied to the cut stump. This method involves spraying the freshly cut stump with a concentrated herbicide solution. It is important that a concentrated solution be applied according to label directions.

A number of herbicides are labeled for stump application including those with active ingredients such as glyphosate, triclopyr and dicamba. It is also critical to treat the stump as soon as possible and no longer than an hour after the top has been exposed to air. Waiting longer could reduce the effectiveness of the treatment.

If the tree has been cut within several weeks, it may be possible to recut the stump by at least two inches to expose moist, live wood and then apply the herbicide.

Cut stump applications generally carry less environmental risks than foliar applications because the herbicide is applied directly to the target plant with less risk of overspray and non-target exposure, with one exception.

It is possible that the treated cherry tree may be root grafted to an adjacent black cherry or ornamental/cherry tree. Instances have been documented where a herbicide has moved from a treated tree to another of the same species or genera through a root graft. While this is not a high probability, in areas where other cherry trees are present, mechanical removal of the tree should be considered.


Jeff Stringer, 859-257-5994