At Tree Docs, we handle every aspect of your oak trees’ needs with unmatched expertise. The most important tool we use to deliver quality care is education. Oak wilt is a vascular disease that causes rapid death, in as little as 1-3 months, in affected oak trees. Having a complete understanding of the Oak Wilt life-cycle and the devastating effects of the disease is crucial. All oak species are susceptible but the Red Oak trees are especially likely to die after infection. The single most important strategy for managing this disease is to protect the trees against injury during the growing season with the greatest risk of transmission is between April 15th and July 15th.
Looking to have your Oak Trees pruned? Time is running out. Mid March, or when the redbud trees bloom, is when all pruning operations must stop.
Two ways oak wilt is spread:
- Above ground by sap-feeding beetles that are attracted to fresh wounding
- Underground through root grafts from neighboring, diseased Oak Trees
KEY POINT: Do not prune from April to November
Other ways trees are wounded:
Tree climbing spikes, rights-of-way pruning, nailing signs on trees, accidental bark removal/injury and storm damage.
What to do if you need to prune your oak tree in the summer or it has been injured during the growing season.
Immediately treat the wound with a tree wound dressing or latex-based paint to seal the wound. When removing whole trees during the critical period, treat the stumps with tree paint to prevent underground disease transmission.
Experts recommend applying a wound dressing to a pruning cut only during this time. Wound dressings should generally not be used.
Preventative fungicide treatments may be used for high value trees and can give 12-36 months of residual control when applied as a macro-injection. See picture below of a preventive injection occurring in an oak tree in the Fairlawn OH region that was treated after a major storm caused damage.
More information from our Ohio State University Extension Specialists: https://ohioline.osu.edu/factsheet/plpath-tree-02
Patterns of dieback in trees
1. Top down:
If you see lots of dead sticks at the top of the tree, look down. Consider that water and nutrients must flow up through the trunk and stems to make it to the top of the tree. Problems in the root zone are the main culprit when disruptions in water flow are seen.
Root collar/zone disorders include:
- Soil Compaction
- Water-logged soils
- Cutting of roots
- Girdling in the root flare
- Buried root flare
- Heavy competition with turfgrass and groundcovers
General decline from the top down indicates a problem down low.
2. Bottom up:
Dieback from the ground up usually indicates a fungal leaf or needle disease. The fungal spores will live in the soil and splash upwards from branch to branch.
This dieback pattern can also indicate strong competition for light.
3. Sectional:
Various causes that result in twig girdling.
- Rodent chewing
- Partial root or stem girdling
- Some vascular diseases
- Localized insect damage (borers, bark beetles)
4. Large deadwood:
May be the most immediate concern for homeowners. Arborists typically consider deadwood to be hazardous when it is over 5’’ in diameter. Sometimes 3’’ is considered when the individual branches are very long or high in the tree. Large deadwood is usually observed in mature/over-mature trees and is considered normal as long as the tree appears to be in good health otherwise. In fact, the term for large trees dying back is known as ‘retrenchment’.
Retrenchment occurs as older trees reach the maximum height and spread and are no longer capable of distributing water, nutrients and energy throughout the entire tree. An arborist who has a good understanding of retrenchment tends to be more cautious with interior thinning because they want to leave strong branches to prune back as the tree ages.
Final Thoughts: Safeguard Your Oaks Today
Oak wilt is a formidable threat that can strike swiftly, compromising not only the beauty of your landscape but also the health of your oak trees. By understanding the disease’s life-cycle and the critical timing for pruning and wound treatment, you can take informed, proactive measures to safeguard your trees. Whether you’re managing seasonal risks or addressing unexpected injuries, the key is to act before the damage becomes irreversible.
At Tree Docs, we’re dedicated to helping you preserve the longevity and vitality of your oak trees. Our expert arborists are ready to provide tailored guidance—from safe pruning practices to immediate post-injury treatments—that protect your trees against oak wilt and other threats. Don’t wait until it’s too late. Contact Tree Docs today for a personalized consultation and ensure your trees receive the expert care they deserve.
