Carl Absher and John Thomason are committed to saving trees.
Mr. Absher, a board-certified master arborist, and Mr. Thomason, a certified arborist, both with ABC Tree Service (Mr. Absher is co-owner), are actively educating the public on saving hemlocks.
Some area hemlocks are seriously threatened by the hemlock woolly adelgid, a microscopic insect, native to Asia, that feeds on plant sap.
According to a news release, the insect is found on twigs at the base of needles on infested plants. By the time it looks like a small ball of cotton, it has gone through one or two generations of infestation.
“The worst infestation in the area is on the northern end of Signal Mountain in the Walden area,” Mr. Thomason said. “There is no evidence that it’s in the valleys.”
The infestation is in the mountains because it’s where the highest concentration of hemlocks are and the insects like cooler air, he said.
The good news is that hemlocks most likely can be saved if specific steps are taken early, he said. He offers these suggestions. For more information, visit abctree.net.
FIVE TIPS
1. Identify the problem. Hemlock woolly adelgid is manageable in the landscape and nursery if it is identified early and treated. There is not yet an effective and economical method to treat the forest trees.
2. Use approved chemicals. Horticultural oils work well when properly applied. They will kill all stages of the insect including the eggs. The oil is available at nurseries and garden stores, and homeowners can treat their own hedges and smaller trees. Larger trees must be sprayed by licensed arborists with power equipment. Systemic insecticides are available that provide from one to three years of protection on hemlocks. Imidacloprid, the most common, may be applied as a soil drench, soil injection or trunk injection.
3. Make sure hemlocks are hydrated. Hemlocks are highly susceptible to drought stress, which can aggravate problems with pests. Hemlocks should be watered deeply during dry periods with at least 1 inch of water per week.
4. Keep the root system covered with mulch. The hemlock typically has a shallow root system that, in the wild, is covered with a layer of forest debris, keeping the roots cool and moist. In the home landscape, keep a 2- to 3-inch layer of mulch over as much of the root system as possible.
5. Be cautious with fertilizer applications. Applying fertilizer can result in a more vigorous and presumably healthier tree. However, research shows that the addition of nitrogen to a tree already infested will result in a more aggressively reproducing population and lead to a quicker death of the tree. Do not use a nitrogen fertilizer on trees already infested.