Although they are underground and out of sight, roots are arguably one of the most important parts of your landscape trees when it comes to providing proper care. Damage can be deadly, so it's important to understand the causes and effects of injury to a tree's roots.
Roots suffer damage from disease, lack of proper care, or mechanical damage. The most common cause of damage is probably watering. Too much or too little water can weaken roots, which then makes them prone to fungal and bacterial pathogens. Wet soil, in particular, is deadly, as the roots drown in wet soil and fungus moves in. Damage can also occur from digging or excavating near a tree. Roots can become severed, or they may suffer damage that allows disease vectors access to the tree.
Wilting of the foliage or dieback starting at branch tips and moving inward toward the trunk are the most obvious signs of root damage. The dieback may only affect one side of the tree, especially if the cause is severed roots. Foliage may change color out of season or drop off while still green. Sometimes the foliage dies and yellows but stays on the branches. If fungal pathogens attack the roots, you may find fruiting bodies like mushrooms growing from the base of the trunk or on the ground right next to the tree. As the roots weaken, a tree may also begin to lean since it is no longer well anchored.
Badly damaged roots, particularly from rot or disease, can kill the tree. Once fungus or bacteria enters the trunk, it may not be possible to treat and save the tree. Further, a tree with root damage is no longer well anchored in the ground. These trees are more prone to blowing down in high winds, causing damage to property and injury to people below. As dieback progresses, large branches may fall to the ground unexpectedly, which poses a major hazard to anyone below.
Recovery depends on the type and severity of the root damage. If disease pathogens have already entered the roots, the tree will likely need to be removed. An arborist must assess the tree to see if recovery is even possible. For minor damage, particularly mechanical damage, trimming back the crown to a more manageable size for the remaining healthy roots may allow the tree to recover. Proper watering and fertilizing will be necessary to ensure the roots are able to regrow and heal.
Contact a tree service company in your area for more assistance.