Naturally occurring trees evolved to tolerate the conditions in which they live. Altogether, native trees can survive even the extremes of their natural environment for short periods. However, trees struggle when extreme situations like heat or drought last longer than usual.
At this point, trees will begin to suffer. In fact, the weather can cause so much damage that the tree dies. Trees will experience heat stress just like an organism in the animal kingdom. If you live in a temperate region, you should pay attention to your trees when temperatures rise above 90F. This is especially true for young trees and elderly trees.
On the other hand, we regularly plant non-native species for ornamental and other purposes. Non-native trees may be less tolerant of the environment they now live. Make sure to accurately research before choosing the trees for your yard or garden. Additionally, pay attention to any trees that are not tolerant to heat or drought when the weather gets rough.
Below, we will discuss the heat stress in trees, the signs of heat stress, and how to protect your trees. Finally, we will summarize five trees that are incredibly heat tolerant.
Can Trees Get Heat Stress?
Extreme heat for a short period is not a huge threat to a tree. Trees store water to sustain themselves in the case of drought or heat. Tress will absorb water from the earth and air. Through photosynthesis, some of this water is lost as transpiration.
If you experience enough rain before a heat wave, your tree can survive better than if it is a period of drought. However, longer periods of heat can cause the tree to lose water.
Heat stress is primarily caused by a tree’s loss of water. Extreme heat is generally associated with drought. So, not only is the tree losing water from the hot sun, but it is also not absorbing as much as it needs to survive.
What are the Signs of Heat Stress for a Tree?
Tress can only exhibit so many symptoms when they are unwell. Many of the symptoms of heat stress mimic other diseases. The easiest way to identify if a tree is suffering from heat stress is the timing of the symptoms.
If an otherwise healthy tree begins to show these symptoms in a drought or heat wave, your tree is likely suffering from heat stress.
The leaves are part of the tree that will experience the most issues from heat stress. Generally speaking, leaves are weaker than the rest of the tree. Moreover, leaves are far away from the trunk and the primary water source.
When a tree has heat stress, the leaves can exhibit the following symptoms:
You may also notice that the tree is oozing sap. If they are present on the tree, blossoms, and fruit may also fall prematurely.
How Do I Protect My Trees from Extreme Heat?
Water
The best way to protect your trees during times of extreme heat is to provide them with water. For trees, sprinklers do not drive the water deep enough into the soil to support a tree.
Drip irrigation or soaker hoses are better. Additionally, these types of water systems provide water to the tree at regular intervals. If the tree is young, you must provide more water than once properly established.
Trimming
When pruning a tree for shape or overall health, it is best to do so in the spring. However, arborists also advise you to remove dead or dying branches from a tree during the heat of summer.
Dead and dying branches attract destructive insects and other diseases.
Keep the Ground Clear
Shorter ground plants can absorb the water from the soil before it reaches the roots of the tree. Clear away smaller ground plants to allow your tree the best chance to grow.
Additionally, asphalt and concrete can radiate heat toward the tree and further complicate the situation. The location of darker surfaces cannot always be remedied, but you can protect the trees located near these surfaces.
Mulch protects trees from heat stress by maintaining the moisture of the soil. Altogether, mulch will slow water loss and maintain the temperature of the ground.
Shade
For young saplings, you should provide shade. Shade cloths can be draped over the tree to protect them. If you are in desperate need, even a beach umbrella can protect your younger trees.
Can Heat Cause a Tree to Explode?
It may sound like a hoax, but extreme heat can cause a tree to explode. As the tree loses its water content, the trunk can collect too many gases. The buildup of gases and destruction of internal tissues will cause the entire trunk to deteriorate.
Larger, older trees can explode because of their sheer size. As the heat stress sets in, the tree begins to die. The tree will weaken until it finally reaches a catastrophic point. Suddenly and violently, the tree will pull itself apart. The sound will be loud, and tree splinters will fly.
Overall, the explosion is dangerous for any bystander or nearby property.
What Trees are the Most Heat-Tolerant?
Like all characteristics, there are some tree species that are more heat-tolerant than others. Most often, trees that are heat-tolerant are not cold-tolerant. You will need to find a good balance for your yard or garden.
If you are in the market for a drought and heat tolerant tree, these five species are the best ones for you:
The silver birch displays the same white bark expected of birch trees. It grows well as a pioneer species. In fact, it can take root after the land is damaged by flood or fire. Silver birches are also tolerant to frost.
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The Indian Bean tree is native to North America. Overall, it grows in the southern states where warmer temperatures are expected. Altogether, this tree does not suffer from many diseases and is left unbothered by insects. Shockingly, this tree is also cold hardy.
The Judas tree grows blossoms along the trunk. It is one of the few tree species with this wonderful characteristic. This tree grows from multiple trunks which allows it to pull water from many directions in the soil.
The Turkish Hazel is not native to North America. However, it is planted throughout much of the United States. It tolerates temperate regions well. Ultimately, the Turkish Hazel can grow almost anywhere. It adapts to varying pH, temperature, and rainfall.
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The Cockspur thorn is a large tree. Not only is it tolerant to heat, but it is also resistant to disease. Cockspur thorns are not tolerant of the cold. Gardeners plant it in much of the United States as well as parts of Canada.
