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Urban tree decline killing Coast trees
The Coast Gardener Newspaper and Web Column - December 29, 2001

It is no surprise that trees living in an urban environment struggle to remain healthy and thrive in the sometimes harsh city conditions. Since renewed concerns have recently surfaced regarding Coast Live oaks, I wanted to address the primary cause of tree death I see on the Coast.

Urban tree decline is nothing new. Many factors contribute to the slow decline in tree health in urban settings. Air pollution, drought, physical/mechanical injury, soil compaction, poor pruning practices, heat reflected from asphalt and buildings, root damage from soil excavation and construction, improper tree selection, overplanting and a general lack of understanding about tree growth and development all contribute to the decline and eventual death of urban trees. These trees often suffer a diseased existence. Those that do survive are sometimes not very attractive.

The causes of tree decline mentioned above often combine with a variety of fungi that attack the stressed trees. A perfect example of this was seen throughout the Coast last summer as a result of fungi attacking drought stressed trees. These secondary infections look like the problem when, in fact, the drought is the "root" of the tree's decline and eventual death.

Most of the fungi are included as heart, butt and root rotting fungi that affect trees structurally. Sometimes fungi that attack the roots will cause tops of trees to die back. Seldom, however, can all of the causal agents in urban tree decline be identified.

Identifying such trees that exhibit urban tree decline symptoms is easy. Affected trees usually show a dieback of the crown, beginning with the uppermost and outermost branches first. Final stages of decline may exhibit symptoms of only a few green sprouts and leaves attached to main branches.

Why does the tree crown begin to die? Frequently, it is because the roots are damaged or diseased. Plants grow with a balanced root/shoot ratio. For example, if a portion of the root system is damaged or diseased, a portion of the crown will die as well.

What can be done? In addition to protecting desired trees from construction damage, proper fertilization, irrigation and pruning techniques are important to the overall health of trees. Healthy trees are less susceptible to the many factors I mentioned earlier that contribute to tree decline.

Always consult with a licensed and bonded certified arborist for proper diagnosis with troubled trees and help with a maintenance program that is right for them. Improper pruning and poor management practices can cause more harm than good. Trees add beauty to a landscape and can increase real estate values by as much as 20 percent. It pays to keep an eye on your trees and make wise choices regarding their selection, care and removal.

I would encourage anyone interested in improving and caring for our urban forests to join the Mississippi Coastal Plains Urban Forest Chapter of the Mississippi Urban Forest Council. The Council is a division of the Mississippi Forestry Commission and strives hard to educate residents about the importance and care of our urban trees. This newly formed Coast chapter is working diligently to soon provide urban forestry educational programs to the people of South Mississippi. Call (601) 856-1660 to see how you can get involved in this worthwhile organization.

These archived gardening columns were written by Chance McDavid, former Harrison County Extension Agent.