2026 Diagnostic Forecast

It is that time of the year again, to review all of the data and observations from the last couple of years, to remember what happened, how trees responded, and how they will likely respond in the coming year.

Weather is the greatest dynamic contributor and influencer of tree health, year to year. The single biggest event of 2025 was the 12-inch rainstorm in August.  That event produced the greatest amount of storm damage to trees from a summer storm in recent years.  The combination of water-weight being constantly added as winds ramped up resulted in many split, broken, or downed limbs, and many trees that fell. The soil supporting the roots got so inundated with water that it turned soupy and often could not bear the weight of the tree!We are and will continue to get calls about newly discovered storm damage in tree canopies. (Look for it now!)

This damage must be addressed for safety and health reasons. Storm damage is bad enough, but unaddressed damaged limbs will be an ongoing stress as tree responses to wounding will try to “heal” that damage through decay compartmentalization and woundwood formation. But this will fail with severe splitting and splintering, and the tree will waste a great amount of stored resources in the attempt. The expenditure/loss of energy resulting from storm damage is a stress factor that lowers tree health and defenses.

Insects are opportunistic to these situations.  Many insects normally present a “burden” that the tree copes with, but this burden is best kept from the tree when it is trying to repair and come back from storm damage. Insects like leafhoppers, scales, aphids, and cankerworms fit this category.  Other insects known as wood borers present a bigger problem and need to be controlled when infestations occur.

Fungi that attack the roots, root rots like Armillaria and Phytopthora, have increased greatly over the period of time we had saturated soils. Disease inoculum of fungal threads and spores remains high in the soil, often resulting in cumulative attacks and decline of trees.  Trees showing poor crown vigor or thinness can be a sign that root disease should be checked for. I expect to see a lot of this kind of damage in 2026. When discovered early enough, much can be done to intervene and help reverse decline tendencies that have manifested. Several root treatments can deter the spread of these fungi and help to retore root system function and extent.

Yes, we will be busy. Much of the success in a given year depends on environmental conditions, and monitoring for signs of stress or pest occurrence. Trust Wachtel Tree Science to help monitor these variables and adjust your program as needed for success in helping your trees live well and prosper!

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