What causes a tree to die from the top down? A common reason for a tree to die from the top down or from its outer limbs is drought. Even with reasonable rainfall, your tree may not be getting the water it needs to thrive and survive.
When a tree begins to deteriorate from the top down, this condition is also known as dieback. Dieback is the gradual death of tree branches, foliage, and/or limbs starting at the tips (extremities) and moving inward toward the trunk. Dieback, as mentioned above may result from drought. However, there may be a variety a variety of causes contributing to the gradual death of your tree.
The following will help you to identify what is causing dieback, the options available to save the tree, and the actions you can take to prevent the tree’s death.
In order to identify the cause of dieback, you need to know what you are looking for. The following are common reasons and symptoms when tree health declines.
Drought – Symptoms include the wilting or discoloration of leaves, limb, twig, and branch dieback, as well as the death of roots. Trees suffering from drought are very likely to be affected by insects, disease, or both.
Soil Imbalance – Soil is composed of minerals, organic and inorganic matter, water, air, and has an acidic or alkaline pH level. When an imbalance of these levels occurs, nutrients needed for the tree’s survival may not be absorbed. This can certainly lead to dieback and death of the tree if not addressed.
A sure sign of soil trouble is the absence of worms, plant growth, and small insects. “Life” should be detected in your soil, if not your soil’s health needs attention.
Insect Infestation – Invasive insect species also cause or accelerate dieback. When trees are stressed, they produce more amounts of nitrogen, potassium and phosphorus. This in turn makes them more attractive to invasive insects that feed off them.
As an infestation grows, the tree becomes more stressed and in turn, produces more of the chemicals – attracting more insects. This process can become a self-reinforced loop, and the initial stressors now combined with the infestation will eventually lead to the death of the tree if not treated promptly.
NOTE: While trees have adapted their defenses and healing processes over the millennia, it is these same adaptations that may feed an insect infestation.
For each of the causes listed above, there is a specific course of action to halt or even reverse it. Once the cause is identified, the following simple treatments may help to save your tree.
Drought Treatment – During dry seasons or when rainfall is scarce, give your trees a thorough watering once a week. Make sure that the soil is soaked to a depth of at least twelve inches. Mulching around your trees base will slow the evaporation process and help the soil and tree retain moisture.
Soil Imbalance Treatment – While calling in a Certified Arborist may be the best option here, you are perfectly capable of getting a soil test kit from your local nursery or home improvement store (gardening department). Use the kit to determine if there is an imbalance for the species of affected tree(s), then seek appropriate soil treatments to return the soil to a healthy composition.
Insect Infestation Treatment – Once an infestation is confirmed, insecticides, traps, and oil can be used to kill the existing insects and prevent further infestation. Read this 72tree.com/using-dormant-horticultural-oil-treat-tree-insect-infestations/ for more on using and applying oils to treat insect infestations.
It is important to note that insect infestations are typically the result of a tree already stressed or in bad health. Once the infestation has been dealt with, begin looking for other stressors that may have lead to the weakening of the tree’s health.
When dieback occurs, saving your tree will involve pruning or trimming off the dead parts of the tree, and identifying the reason that the dieback occurred. Once identified, treat it. If it is an infestation that is threatening other trees and plants, you may have to make the decision to completely remove the tree to prevent further contamination and damage.
Proper Treatment and Prevention – Once you have treated the cause of your tree’s dieback, understand that you can save a dying tree by simply paying attention to it through the seasons. Your tree will show signs of stress, and once you detect it, consider it a call to action.
It is equally important to establish and follow seasonal maintenance and care. Bringing in a Certified Arborist or reputable tree service to inspect your trees and landscape will help give you the upper hand in keeping your trees healthy!