This blog series will cover several aspects about trees, the conditions and problems we may see on these stately cornerstones in our landscapes. This first blog will cover bark and trunk issues and what can be done to fix problems if they appear.
Wet Wood –
Also known as slime flux, wet wood is quickly identified by the water-soaked appearance of a leak running down the trunk. It is caused by a build up of bacteria inside the woody part of the tree, possibly at a junction of branches, that eventually finds its way through a crack and oozes out of the tree.
This slimy material usually smells, especially when newly developed, and may continue to be produced for a time.
There is no practical solution for correcting this problem. The only downside is appearance, as this condition doesn’t affect the overall health of the tree. The stain from the slime flux is reduced over time (see photo – drainage was much more obvious 5-7 years ago) but the original leak rarely disappears altogther.
Smooth Patch –
This is a non-threatening condition where the rough outer layer of bark sloughs off, leaving behind a smoother, lighter- colored and somewhat sunken, patch of bark. It can be caused by several different types of fungus, which are active in wet weather, and can spread to other trees.
This condition is commonly found on white oak, maple, ash, willow, and basswood, though some other trees can be affected.
Peeling, Loose, or Cracks in the Bark –
Any of these conditions represent a health problem to the tree and can be caused by:
Weather Damage
Missouri is known for it’s sudden weather changes, and that can wreak havoc on tree bark. During the winter, the outer bark can expand with warm temperatures, whereas the inner wood doesn’t fluctuate as quickly. This tension between the two materials can cause peeling.
During wet weather, bark tends to swell, then when the sun comes out, it can dry the bark too quickly and may split away from the tree.
Sunscald occurs on the south or west side of trees during the summer months, with the long days and bright light, but also in winter where we can still have periods of high light intensity. The bark gets sunburned and dies, eventually peeling off. Protect the trunk of young trees with light-colored tree guards during the hot summer months (June-Aug) and cold winter months (Dec-Feb)
Pests
Bark Beetles bore into the inner bark to feed and lay eggs right in the cambium, the most critical part of the bark where nutrients flow to the rest of the tree. Keeping the tree healthy is one of the best defenses against this destructive pest. If an infestation occurs while a tree is young, Sevin and Pyrethrin can be sprayed at the first sign of attack.
Borers can do a tremendous amount of damage to a tree within 2-5 years depending upon age and health. Once present, tree health declines resulting in loosening bark. Borers are drawn to trees that are stressed (drought, poor drainage, soil compaction, mechanical damage). They can be easily controlled if caught early with the systemic insecticide, Imidacloprid. Inspect trees monthly from April to August for signs of active holes.
Animals can also damage tree bark:
- Rodents and small animals like squirrels, rabbits, mice, and cats
- Birds like woodpeckers and sapsuckers
- Larger animals such as deer rubbing their antlers and bear rubbing against a tree. We don’t have many bears in our area (yet).
Disease
Certain fungal diseases can infect the bark and cambium layer, cutting off the nutrient flow causing bark detachment.
- Armillaria Root Rot – Armillaria root rot is a root disease caused by a colonizing fungus that typically infects trees that are weakened or stressed by drought, root damage, defoliation (leaf loss), or other causes.
- Anthracnose – Though this is mainly a leaf disease, it can affect twigs and bark showing up as brown patches, lesions, and peeling bark.
- Bacterial Diseases – Infections can occur with any wound, especially if wet weather follows soon after and the tree hasn’t had time to set up it’s defenses against infection. This can be seen with cherry when a sudden cold spell in winter is followed by a wet spring. Cracks form in the bark from the excessive cold, then bacteria forms inside the wound in spring and spreads quickly during wet weather to form an infection.
Cleaning up diseased bark debris is the best defense as it reduces further contamination. Spraying with fungicide can help control infections if caught at an early stage.
Environmental Stress
We see all of these conditions affecting the health of trees in Missouri:
- Drought – Under excessively dry conditons, the bark dries out, cracks, and falls off. Water young and newly planted trees weekly for the first two years to reduce damage. Mulch placed around the root zone helps to retain soil moisture.
- Poor Drainage – Excess moisture around the roots doesn’t allow them to breathe, plus poor drainage conditions encourage diseases that can affect the bark. For long periods of time, plant health will be compromised.
- Wet Weather – In spite of good drainage, long periods of wet weather can still cause issues. Wet spring weather can cause trees to grow quickly, resulting in cracks forming in the bark. This is most likely to happen with young trees and those with thinner bark (maple, cherry, peach, and plum to name a few). See photo below.
Reduce trunk and root damage with a wide mulch ring. - Soil Compaction – Heavy foot or vehicle traffic compacts the soil, reducing oxygen levels and actually damaging the roots. Re-directing traffic away from the tree and adding a layer of mulch around the root zone will protect the soil and root-growing area.
- Mechanical Damage – Weedeaters, lawn mowers, and other maintenance tools are the cause of many bark wounds leading to insect and disease issues. Maintain a wide mulch ring and protect the trunk with tree guards. Bark can also be damaged with improper pruning techniques.
Other photos:
