Tree Stressors and Tree Decline

People aren't the only living thing that can get stressed - trees can too. In fact, tree stress is a serious problem that not only causes significant damage to your trees but also can kill them.

So what causes trees to get stressed? The first is environment. Just like humans, the environment we are surrounded by affects trees. Stressful environmental conditions such as extreme temperatures, poor soil, and physical damage to leaves, bark and roots can predispose a tree to secondary insect and disease attacks. Extremely wet soil can also stress a tree as can soil compaction and freezing.

Trees are also surprisingly affected by other conditions that are caused by man or animal. For example, lawnmowers are one of the major causes of damage to trees. Improper pruning also stresses trees. Too much pruning or pruning during the wrong time of year can harm your tree more than help it. Over watering trees also causes trees great stress, just as flooding or too much rain could. Frequent watering results in roots that are too wet for good growth.

Other human caused stresses are improper handling before planting your tree, construction damage and the use of deicing salts or herbicides. Tree wounds caused by humans can also make your tree quite susceptible to outside influences and therefore make the tree deteriorate over a period of time.

The problem with tree stress is that from the human eye, you may not recognize that your tree is stressed right away. Of course there is obvious stress such as that caused from storms, but the small stresses are also very critical to a trees survival as well. Trees often do not display immediate responses to stresses because of their accumulated growth habit. But when your tree is stressed you will begin to notice that it will change. In some cases, the process of photosynthesis, which is the primary supply of carbohydrates for all tree functions, is reduced and the tree’s stored food reserves are depleted. And if the root systems are also damaged, the tree will be unable to produce sufficient carbohydrates and growth regulating chemicals.

Symptoms of distress will begin to show as your tree deteriorates. The leaves may decrease in number and become smaller in size. Some trees will produce excess fruit or seed - this is its way of trying to survive. Branches will begin to die, and the root system of the tree becomes reduced. From here the tree will continue to decline until the eventual death of the tree, which can take from 2 to 15 years. For many trees, once the decline has reached a certain point, it cannot recover.

If the actual physical stressors to the tree don't kill it, the reduced strength of the tree will leave it vulnerable to disease and insects. The addition of these elements can speed up the trees decline.

Trees in urban areas are often stressed more than those that are in rural areas - this is due to restricted root space, building foundations, streets, driveways and other obstacles that limit the expansion of tree roots and significantly reduce the amount of water and minerals available to the tree. Compacted soils and competition also stresses urban trees.

If you feel your tree has been recently stressed, consult with your local tree professional or arborist for some proactive measures you can take. Trees can be quite resilient and with a little care, they can potentially make a full recovery.


Andrew Johnson is the owner of Central Texas Tree Care, a leading tree service provider in Central Texas (Travis County and surrounding areas) offering services such as pruning and removals, cabling and bracing as well as arborist reports, diagnostics, pest management, fertilization and Austin tree service trusts. For more information please visit http://www.centraltexastreecare.com.