subject: How To Tell If You Have A Diseased Tree [print this page] A healthy tree has an amazing ability to adapt and survive and is designed to withstand the harshest of elements. Trees are living, breathing things, and like humans, they can get sick and die.
Tree disease can take down even the mightiest oak or redwood, but many put up a fight much like a person would when faced with a potentially deadly sickness. A completely disease-free tree is rare because of the many microscopic organisms that live on trees -- in the bark and in the root tissue.
But trees are tough and usually can co-exist with the pathogens. But sometimes tree disease can take hold in such a way that doesn't allow for recovery.
When this happens, the tree can become susceptible to other diseases, and if it can't save itself, humans can step in and lend a hand. But just like a doctor treating a patient, sometimes a tree is so far gone that it becomes a liability.
A diseased tree that's near death in your front yard can fall on your house and leave you with a new set of problems. When it's too sick to save, the tree needs to be removed.
Common Tree Diseases
There are many different diseases that can impact trees, and most are specific to a particular species of tree. Anthracnose is a disease that goes after hardwood trees, particularly American sycamores, white oaks, dogwoods and black walnuts.
Anthracnose is widespread in the eastern part of the United States where there is a high concentration of these families of trees. Common symptoms include discolored blotches or dead areas on the leaves, also known as leaf blight.
Anthracnose is caused by several types of fungi that reproduce by means of spores. Spores are microscopic particles that spread through the air, especially during windy and rainy periods.
They need wet weather to germinate, so anthracnose may become severe during years with long rainy periods. If a tree gets severely infected, it may lose its leaves, which is called defoliation.
A round of anthracnose won't kill a tree, but repeated defoliation can weaken the tree and make it susceptible to other diseases. Its biggest impact is the reduction of shade trees in urban environments. Root decay, or root rot, is another common cause of disease or death in trees.
Roots secure the tree to the ground. They also supply nutrients and water, and the older the tree is, the larger the root structure.
Trees with root problems can get blown over in wind or even fall over without warning under the weight of its leaves. It's hard to tell if your tree has root decay.
There are two indicators to help determine if your tree has root decay: if the roots are broken or there is evidence of fungus. Another devastating tree disease is the chestnut blight fungus, which has nearly wiped out the American chestnut from eastern forests.
A healthy tree is strong and robust, but it can go south in a number of ways. Factors like wind, rain and extreme heat and cold can affect the health of a tree.
These environmental causes can't be controlled, so it's important to keep an eye out for any early symptoms of ill health. Trees need to be inspected routinely: once each season and especially after severe storms.
Healthy trees have full crowns, the area of branches and leaves that extend from the main trunk. Don't let green leaves fool you, though -- trees can be sick and still have a lush, green crown.
Saving a Diseased Tree
As with any disease, avoiding it is preferable to treating it and a healthy tree is inherently more disease-resistant. In order to keep your trees healthy, try the following steps:
Avoid putting weed fertilizer on grass anywhere near the tree's roots. If you mulch around the tree, leave a little space around the trunk to let it breathe and avoid rotting the wood.
If your tree has exposed roots, hand trimming that area is preferable to using a lawn mower or anything with a sharp blade. Watering trees during droughts is important because tree roots move up toward the top of the ground in search of water, which can weaken the tree's root structure.
Proper pruning practices are vital, because a wrong cut can leave the tree susceptible to disease. Different species have different requirements for how to prune, so consult your local nursery or tree specialist for instructions on keeping your tree trimmed and healthy.
