Trees work hard.

They provide shade on hot afternoons, shelter for wildlife, cleaner air, and beauty throughout the year. Because they seem so strong and established, it’s easy to assume they can handle whatever summer brings.

But even mature trees experience stress.

In Wisconsin, summer often brings a mix of heat, humidity, dry periods, strong storms, and occasional pest pressures. Understanding how trees respond to these conditions can help you recognize problems early and support the long-term health of one of our landscapes’ most valuable assets.

Why Summer Can Be Hard on Trees

While spring is a season of growth, summer is often a season of endurance.

As temperatures rise, trees work harder to move water from their roots to their leaves. Extended dry periods can make that process more difficult, especially for newly planted trees or trees growing in compacted urban soils.

In Wisconsin, periods of drought are often followed by heavy rain events, creating additional challenges for root systems and soil moisture management.

Most healthy trees can adapt, but prolonged stress can make them more vulnerable to pests, diseases, and long-term decline.

Watch the Leaves

One of the easiest ways to assess tree health is by paying attention to its leaves.

They are often the first signs of stress!

Keep an eye out for:

• Yellowing leaves during the growing season
• Brown or scorched leaf edges
• Curling or wilting foliage
• Leaves dropping earlier than expected

Not every yellow leaf is cause for concern. Trees naturally shed some leaves throughout the season. However, widespread changes throughout the canopy may indicate environmental stress.

Watering Matters More Than You Think

Water is often the most important factor affecting tree health during the summer.

Newly planted trees are especially vulnerable because their roots have not yet expanded into the surrounding soil. Even mature trees can struggle during extended dry periods.

When watering:

• Water slowly and deeply
• Focus on the root zone rather than the trunk
• Water less often but more thoroughly
• Avoid frequent, shallow watering

Deep watering encourages roots to grow downward where moisture is more consistent.

Don’t Underestimate Mulch

One of the simplest ways to support a tree is also one of the most effective.

A properly applied mulch ring helps:

• Retain soil moisture
• Reduce competition from grass
• Moderate soil temperatures
• Improve soil health over time

Mulch should be spread in a broad ring around the tree, but never piled against the trunk.

Those volcano-shaped mulch piles often seen around trees can actually trap moisture against bark and contribute to rot.

Pay Attention to Changes

Summer is also a time when pests and diseases become more noticeable.

Watch for:

• Unusual spots on leaves
• Large sections of missing foliage
• Cracks or wounds in bark
• Insect activity that seems excessive

In Wisconsin, homeowners may hear about concerns such as Emerald Ash Borer, oak wilt, or Japanese beetles. While not every issue requires intervention, becoming familiar with your trees and noticing changes early can help identify problems before they become more serious.

Healthy Trees Support More Than Themselves

Trees are much more than landscape features.

They provide food and habitat for pollinators, birds, insects, and countless other organisms. Their roots stabilize soil, their canopies cool surrounding areas, and their leaves help support the ecosystems around them.

A little observation, thoughtful watering during dry periods, and proper care can help ensure they remain healthy for years to come.

When trees thrive, entire communities of plants and wildlife benefit!

Experience Healthy Woodlands Through Woodland Wonders

Throughout Woodland Wonders presented by Selner Tree & Shrub Care, guests are invited to look more closely at the important role trees play in shaping the landscape.

As you explore the exhibit, notice how trees create shade, support diverse plant communities, and provide habitat for wildlife. Look at the layers beneath the canopy and consider how much of the woodland depends on healthy trees.