By Marilyn Shy
The snow is melting, the birds are singing, and you are out talking a walk in your yard. Suddenly you notice something different about that tree in the corner. It doesn’t look right. As a matter of fact, it looks downright unhealthy. What could possibly be wrong with it?
It’s a good time of year to take notice of these kinds of things. With the proper identification and follow-up care, you may be able to save the tree, or at the least stop the disease from spreading to other trees. Here are a few possibilities.
Salt Spray Injury
If you have trees near a road or driveway where salt is used, salt spray injury is common, especially on white pine. Injury first appears as a browning of the needles at their tips, progressing to their base. Browning is evident in the early spring and becomes more prominent as the season goes on. As the injury continues, needles drop prematurely and the branches become bare.
On deciduous trees, salt spray can affect the opening of buds in the spring, with flower buds being the most sensitive. Injured buds are slow to open, or fail to open at all. Salt symptoms can include reduced green leaf coloration, smaller leaves with scorched margins, and dying crowns.
Although all trees can be affected by salt injury, some species are more tolerant than others. Most vulnerable are white pine, spruces, hemlock, red and sugar maple, serviceberry, hawthorn, beech and red-osier dogwood. More tolerant species include birch, ash, red cedar, cottonwood, aspen, cherry, most oaks, elms and yews.
To correct salt damage, soils can be irrigated before spring growth. A general rule of thumb suggests that 6 inches of water should be applied to leach salts out of root zones.
Needle Cast
Non-native spruces, especially blue spruce, can suffer from a serious disease called needle cast. The needles turn grayish-green, brown, or purple, then die and drop off the stems. This is most evident in May or June. The infecting fungus is more frequently found on the north side of trees, in high density plantings, and on wet ground. In other words, when the needles stay wet, there is a greater chance of the fungus infecting the tree.
Needle cast diseases can be effectively controlled with fungicides containing chlorothalonil. It is best to get professional advice to determine timing and selection of spray.
Oak Wilt
Members of the red oak family are most susceptible to this disease. White oaks may decline, but may also recover from it. The most common symptom is a sudden leaf shedding within several weeks of being infected. The fallen leaves may range in color from pale green, to olive green, to normal green. Sometimes the leaf tips may be a tan color. It is very alarming for tree owners to see one or more of their oak trees dropping all of their leaves in the middle of the summer. If you witnessed this last year, now is the time to get help, as the disease can spread.
Because oak wilt is so devastating, it is very important that an accurate diagnosis be made before any management procedures are implemented.
There are a few things you can do in order not to spread the disease. Most importantly, don’t move firewood. Don’t take it to camp, and don’t give it away to family and friends.
Sometimes illnesses can be diagnosed by taking a picture. Larry Czelusta, Conservation District forester, recommends that you take a photo and email it to him at: larry.czelusta@macd.org. You can also call him at (231)775-7681, ext. 3. Larry is available to make site visits in Kalkaska and Wexford Counties. He is very willing to help you diagnose what is wrong with your tree, and come up with a plan to best take care of the problem.