Environmental stress takes a toll on trees

Every year in Kansas we see quite a variety of tree issues in home landscapes that can seem puzzling.  This year hasn’t been any different.  In the last week many tree owners have noticed late summer symptoms such as leaf scorching or color change and a lot of leaf dropping due to the heat. Other symptoms such as limb dieback, fungal growths, bark splits and cracks, cankers, leaking sap, and more that seem to be perplexing have been spotted as well. When these damaged trees are examined closely a common cause can often be discovered.

Leaf scorch caused by late summer heat

Stress is the common thread

The commonality between many tree problems in Kansas is that abiotic (non-disease) causing factors are often the instigator of the problems.   It might be surprising to many to realize that most tree problems in Kansas actually result from these abiotic factors such as environmental stress, improper planting, or soil problems and not diseases. 

Environmental stress/winter injury on Sawtooth oak

Up and down stressful weather patterns over the last several years have put many trees under great stress.  In some cases, it may have been just one stressful event such as a severe early or late freeze, or excessive winter cold injury, but often it is the culmination of several years’ worth of stress that is just now beginning to show up.  Stress in general lowers a tree’s natural chemical defenses which in turn can lead to many other problems.

Stress leads to disease

Wetwood/slime flux disease on a very stressed willow tee

When trees start showing signs of disease such as cankers, leaking sap, or fungal growths on the trunk the disease itself is usually not what caused the tree decline.  The real issue is a stressed tree with very a greatly diminished ability to defend itself.

Canker diseases and decay often show up after a tree has been stressed by things such as weather, storm damage, or even poor pruning.  The problem is that there are generally no totally effective controls for these types of diseases once they are present in a tree.  The most effective thing that can be done is to prevent problems beforehand by reducing tree stress with proper tree selection, planting, care and monitoring.

Observe trees carefully

Trees need to be observed regularly to catch signs of stress and determine if any intervention will help.  To evaluate the health of a tree look first at the trunk then look up.  Look for any sunken or diseased areas on the trunk.  Also look for any fungal growth that could indicate decay.  Then look up.  Look for areas of dieback in the top of the tree, evaluate the leaf cover and color and finally look for new growth.  There should be several inches of new growth being put out by a healthy tree each year.

Be proactive with trees

The large number of tree problems related to stress signals a need to be wise in how we approach tree selection and care in the future.  It is imperative to plant the tree species that are best adapted to and can tolerate our Kansas weather and soils.  Due to the unique challenging conditions that Kansas is known for it will be important to be proactive with trees.  Starting with correct tree selection, proper planting methods, and following through with preventative and proactive care throughout the tree’s life will ensure we have trees to enjoy long into the future.

Read more about planting a tree properly