Trees that suddenly turn brown

By Larry Williams, UF/IFAS Extension Agent, Okaloosa County

It’s not uncommon to see a tree suddenly turn brown during this time of year. Other surrounding trees of the same species will still be green. So the brown tree stands out like a sore thumb. It’s no wonder the tree’s owner becomes concerned.

Tree research conducted twenty-five to thirty years ago showed that at least fifty percent of a tree’s root system would be nonfunctioning or dead before the tree exhibited aboveground evidence that it had a problem. This generally means that by the time a person notices the problem it’s too late.

When you see a tree that appears to suddenly die, you are usually dealing with a tree that has had problems for quite some time (sometimes months or even years prior to the trees death).  

Homeowners will sometimes call and make a statement such as, “all the leaves on my tree suddenly turned brown but are still hanging on the tree and are firmly attached.” I usually respond by telling the caller that this is an indication of severe root injury. Usually a combination of factors over a long period of time caused extensive root injury. The tree had been functioning with a weakened, smaller root system. The extended hot weather ends up being the "straw that breaks the camel's back" for these already stressed/weakened trees.

Some common causes for lethal root injury in trees include construction damage, floods, drought, hurricanes and herbicide injury (many trees are damaged by "weed and feed" products). It very well can be a combination of several factors that ultimately does the tree in. Vascular diseases and insects may be involved but they are usually secondary. The bad news is there is nothing that can be done to correct this kind of injury in trees. These types of problems are prevented, not cured.

The initial damage could have been caused years prior to the tree's leaves suddenly turning brown. Based on my experience, trees in this category do not recover. I think many homeowners want me to tell them that there is a blue box on the shelf at some garden supply store that they can purchase and apply to the dying or dead tree and then the tree magically comes back to life. I don’t like being the bearer of bad news but I do like to “shoot straight” with people. By the time a person is aware that a tree is in trouble, it is usually too late to reverse the problem. But knowing this may help you not waste your time and money attempting to cause an already dead tree to live.

Originally published Aug., 2007