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Heat Stress

It’s Too Darn Hot

Sultry jazz numbers aside, humans can stand in front of the fan or crank up the AC when it gets too darn hot.

Trees aren’t so lucky.


Cool Down.

Humans sweat when we get hot or stressed, allowing evaporation to lower our body temperatures and keep us cool.

Trees similarly transpire (evaporate) water from their stems, leaves, and flowers.


What is Heat Stress?

Heat Stress occurs when high temperatures affect a tree's growth and health. In some cases, heat stress can lead to tree death.

Dead Tree

 The hotter the temperatures outdoors rise,; the more water uptake is needed for a tree to transpire. Surrounded by heat-absorbing building materials, California Urban Forests can’t walk themselves to a local cooling station to find reprieve.

With more water needed to keep the tree’s “body temperature” regulated, less water can be used for essential life functions, like photosynthesis.


What Does Heat Stress Look Like?

Heat stress ensues with less water in their systems and more heat pressure.

Heat stress on a tree looks like: wilted leaves and twigs, leaf scorch, “sunburns” on the branches, leaf drop, discoloration of leaves, and limited growth of the shoots and roots.

How to Prevent Heat Stress

For one, don’t give your trees Gatorade to help nutrient uptake!

Keep the soil moist with good cultural practices (consistent and deep watering schedules). 

Mulch, mulch, mulch! Adding vegetation to “trap” cooler soil away from the sun’s rays helps a tree recover from heat stress.


Fun in the Sun

If your tree looks like it’s had too much fun in the sun, call the team of ISA Certified Arborists at Sims Tree Health Specialists!


About Sims Tree Health Specialists, Inc. 


Sims Tree Health Specialists, Inc. is dedicated to the preservation, education, improved health, and safety of trees. Sims THS has provided California’s Urban Forests with premium healthcare since 1972. To learn more, visit our website:

Sims THS offers services with our ISA Certified Arborists in the following:


Diagnosis and Disease Management, Pest Suppression, Organic Solutions, Fruit Suppression, Drought Protection, and Arborist Assessment Reports and Preservation Plans.


In addition to providing quality tree health services, the Sims family is known for their educational pursuits. In 1996, they started the Sims Tree Learning Center (TLC), a 6-acre botanical garden and research facility sponsored by Sims Tree Health Specialists, Inc. The facility houses multiple types of gardens including a cactus and succulent garden and one of the largest collections of Palms in the Inland Empire. Learn with us!

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