Dallas summers don't ease up. When temperatures stay above 100°F for weeks at a stretch, your trees are working harder than you realize — and the signs of heat stress are easy to miss until it's too late.

The tricky part: heat-stressed trees don't always look dramatically sick. The symptoms are subtle at first, and by the time a tree looks obviously distressed, the damage may already be severe. Here's what to watch for.

Heat stress happens when a tree loses water through its leaves faster than its roots can absorb it from the soil. Dallas summers combine three conditions that make this worse: extreme heat, low humidity, and drought. Even trees that are regularly watered can struggle when temperatures stay above 95°F for extended periods.

Young trees, recently transplanted trees, and shallow-rooted species are most vulnerable — but even mature, established trees can show stress during a severe Dallas summer.

This is the most common and most misdiagnosed sign of heat stress. Leaf scorch looks like the edges and tips of leaves have been lightly burned — they turn brown and crispy while the center of the leaf stays green.

Homeowners often mistake this for a disease or pest problem and start treating for the wrong thing. Leaf scorch is almost always a water issue: the tree can't move water to the leaf margins fast enough to keep up with evaporation.

What to do: Deep water immediately. Apply 2–3 inches of mulch around the base (keeping it away from the trunk) to retain soil moisture. If scorch is severe and widespread, call a certified arborist — the tree may need additional support.

If your tree is dropping leaves in July or August, that's not normal. Some trees will shed leaves early as a survival mechanism — reducing their leaf surface area means less water lost through transpiration.

This is the tree essentially going into self-preservation mode. It's a serious sign that the tree is under significant stress.

What to do: Don't assume the tree is dying. Water deeply and consistently. Avoid fertilizing during heat stress — it pushes new growth the tree can't support. Monitor for recovery in the fall.

Leaves that wilt during the hottest part of the afternoon are normal — that's just the tree managing water loss. The problem is when leaves stay wilted in the morning, after temperatures have dropped overnight.

Morning wilt means the tree couldn't rehydrate during the cooler nighttime hours. That's a sign the root system is struggling to absorb enough water, either because the soil is too dry, too compacted, or the roots are damaged.

What to do: Check soil moisture 6–8 inches down. If it's dry, you're underwatering. If it's wet, you may have a root problem — compaction, root rot, or construction damage. A tree inspection can identify the cause.

You might notice vertical cracks in the bark on the south or southwest side of the trunk. This is sunscald — direct sun exposure heats the bark unevenly, causing the outer layers to crack and separate.

Sunscald is more common on young trees and thin-barked species like maples, but it can happen to any tree during an extreme Dallas summer. Once the bark cracks, the tree is vulnerable to insects and disease entering through the wound.

What to do: Young trees can be wrapped with tree wrap or protected with a light-colored guard to reflect heat. For mature trees, the priority is keeping the tree well-watered and healthy so it can compartmentalize the damage.

Healthy trees put on new growth throughout spring and into early summer. If your tree stopped producing new leaves or shoots earlier than usual, or if new growth looks pale, small, or weak, heat stress is a likely cause.

This sign is easy to miss because it's an absence of something rather than a visible symptom. Get in the habit of checking your trees for new growth during the growing season.

What to do: Compare this year's growth to previous years. A significant reduction in growth over two or more seasons is a red flag that warrants a professional evaluation.

Frequent shallow watering is one of the most common mistakes Dallas homeowners make. It encourages shallow root growth, which makes trees even more vulnerable to heat and drought.

The right approach:

• Water deeply and infrequently — 1–2 times per week during extreme heat
• Apply water slowly at the drip line (the outer edge of the canopy), not at the trunk
• Use a soaker hose or drip irrigation for 30–60 minutes per session
• Water in the early morning to reduce evaporation

A 3–4 inch layer of organic mulch (wood chips, shredded bark) extending to the drip line is one of the most effective things you can do. It reduces soil temperature, retains moisture, and improves soil health over time.

If your tree shows multiple signs of heat stress, or if symptoms don't improve after consistent watering, it's time to call a certified arborist. Some situations that warrant a professional evaluation:

• Significant leaf drop combined with wilting
• Bark cracking or splitting
• Dead branches appearing in the canopy
• A tree that has been stressed for two or more consecutive summers

Heat-stressed trees are also more vulnerable to secondary problems — insects like borers and diseases like hypoxylon canker are opportunistic and will attack weakened trees. Catching these early makes a significant difference in outcomes.

Tree Crew's certified arborists serve Dallas and the surrounding DFW area. If you're concerned about a tree on your property, contact us for a free evaluation.