Drought, Then Flooding: Why Central Florida Oaks Are Failing Right Now

Central Florida just came out of a drought and went straight into weeks of heavy rain and flooding. I've been noticing something in the field throughout — codominant oak stems failing without warning. Some of the failures happened during the drought on quiet still afternoons. More recently, they've been happening as saturated soil and wet-foliage weight push already-weakened trees past their limit.

If you have oaks on your property, this is the season to pay attention. Here's what's going on.

What a Codominant Stem Is

A codominant stem is when a tree grows two or more roughly equal-sized stems from a single point, forming a V or Y-shaped union. Instead of one dominant trunk with lateral branches, you have two (or more) competing stems trying to be the main trunk. It's extremely common in live oaks, laurel oaks, water oaks, and sand live oaks — the exact species most Central Florida homeowners have on their property.

Structurally, codominant unions are weaker than single-stem structures for a few reasons:

- Bark can get pinched inside the union as the stems grow together — called "included bark." That included bark is essentially a fault line built into the tree.

- Wind loads and weight stress amplify at the union point.

- Both stems compete for water and nutrients, which affects how wood at the union develops.

- Reaction wood — the specialized wood trees form to strengthen weak points — often doesn't develop properly at codominant unions.

Under normal conditions, a codominant tree can stand for decades without issue. Under stress, that weak union becomes the first thing to fail.

Why Drought Sets Trees Up to Fail

Trees under drought stress do something people don't always realize — they start shedding weight to survive. Roots can retract or die back. Water-conducting tissue (xylem) develops small air bubbles called cavitation, which permanently weakens the tree's ability to move water. Wood strength drops as the tree prioritizes survival over structural growth. In extreme cases, oaks will drop entire limbs to reduce the water demand on the remaining crown — called summer branch drop.

For codominant stems specifically, drought is a triple hit: the already-weak union has less structural strength than before, the competing stems fight harder for less water, and the wood holding the union together has degraded.

That's why codominant stems that were "fine" a couple years ago can now fail spontaneously — often on hot, calm afternoons when the tree is under maximum water stress. No wind, no storm, no warning. Just a loud crack and half a tree on the ground.

Then the Flooding Finishes the Job

Once rain returns after a drought, most people expect the trees to recover. Some do. Many don't. The drought damage doesn't just reverse — and the sudden swing to saturated soil actually introduces a whole new set of failure modes:

- Root plates lose anchoring in saturated soil, meaning trees can tip or uproot even with modest wind

- Wet foliage adds significant weight to already-compromised branches and unions

- Trees that lost fine roots during drought can't process the sudden water availability, causing internal stress

- Fungal pathogens that thrive in saturated soil (like Ganoderma root rot in oaks) accelerate in weakened trees

- Cavitation damage in the wood from the dry period doesn't heal — it's a permanent structural change

The result is a two-punch failure pattern: drought damages the tree structurally, then flooding either finishes off the weak unions with weight and wind, or takes whole trees down at the root plate. I've been seeing both, and I expect to keep seeing them through the rest of this season.

What to Watch For

Some of the warning signs I look for during a risk assessment:

- V-shaped stem unions rather than U-shaped (U-shaped unions are much stronger)

- Visible seam, ridge, or bulge at the union indicating included bark

- Bark cracking or splitting at or above the union

- Sap oozing, seeping, or dark staining at the union

- Vertical cracks radiating from the union up either stem

- Recent branch drops from the same tree — any limb drop deserves attention right now

- Canopy dieback, thinning foliage, or undersized leaves (lingering drought stress)

- Sudden change in canopy symmetry

- New lean since the flooding started (a sign of root-plate movement)

- Standing water within the dripline that isn't draining

- Fungal fruiting bodies (mushrooms, conks) at the base or on the trunk

- Soil heaving or cracking near the trunk

If you have a codominant oak within striking distance of your home, driveway, roofline, or an area where people spend time — right now is the time to get eyes on it.

What to Do

Not every affected oak needs to come down — most can be safely managed. Options depending on the specific tree and situation:

- Prescription pruning to reduce weight on one or both stems, lowering the load at the union

- Cabling or bracing — installing hardware that supports the union and prevents catastrophic failure

- Improving site drainage where possible to reduce saturated-soil root damage

- Proper mulching — 3 to 4 inches out to the dripline, never touching the trunk — to moderate soil moisture and protect the root flare

- Removal, only when the risk to targets is too high and the union or root system is too compromised to manage

The only way to know which option fits a specific tree is an on-site inspection. That's what a tree risk assessment is for — someone with training in structural and root-plate evaluation looks at the tree, considers what's below it, and gives you a written finding you can act on.

Working With Climb Corps

Climb Corps LLC provides independent tree risk assessments and written arborist reports across Central Florida — Hernando, Citrus, Marion, Sumter, Lake, and Orange counties. If you have oaks on your property that are worrying you after this drought-to-flood swing, we can come out, evaluate them, and give you a written report with specific findings and recommendations.

To schedule an on-site assessment, contact Climb Corps at (352) 397-4309 or climbcorpsllc@gmail.com.