Sunlight is essential for tree growth and survival. It triggers the photosynthesis process, enabling the tree to produce the vital sugars it needs to grow. However, as with anything in life, too much of a good thing can be damaging. In the case of trees, over-exposure to the sun can lead to a condition called sunscald.
What is Sunscald?
Sunscald is similar to how humans get sunburned when they spend too much time under the sun. In mild cases, the damage is simply aesthetic and the tree will likely recover on its own. However, when the damage runs deeper, this can often end up being permanent. Damaged bark can sometimes expose the inner tissues of a tree, and some trees simply don’t recover from this.
Do All Trees Get Sunscald?
Fortunately, sunscald doesn’t affect all trees. Some species, such as the Dragon Tree and the Grass Tree, have evolved under the scorching sun. They’re able to tolerate these conditions just fine.
However, other trees, such as the Mango Tree and the Olive Tree, are more susceptible to sunscald. Trees with thinner bark tend to be more vulnerable too.
What are the Symptoms of Sunscald?
If sunscald is affecting your garden trees, you’ll notice that the bark starts to discolour. It will usually turn a reddish brown, but this does depend on the tree species. As this progresses, the bark will start to split, exposing the wood within. This is often enough to bring pests over, which can spell disaster for a tree. While it may have been able to previously recover, pests that start eating away at the insides of a tree will make that near-impossible.
In addition to the bark, you’ll also notice that the leaves of your tree start to discolour. They’ll turn a bronze colour, before wilting and dying.
How to Prevent Sunscald
Fortunately, there are a few things that you can do to prevent sunscald from impacting your garden trees. The most common is to block the sun. Providing just a small amount of afternoon shade is often all that’s needed. You can do this by draping some shade cloth over your tree, or by using white paint to reflect the light.
Growing your trees in pots can be helpful too. This will allow you to move them in and out of the shade as needed. After all, the weather now fluctuates more than it has in the past – some summers may be cool enough for your tree to handle the heat, whereas others might prove to be too hot. Since you might need to move your trees around frequently, go for a lightweight pot material, such as GRC.
Finally, pay close attention to pruning. If you know that you’ve incorrectly pruned your tree and have taken away too much, then this leaves parts of tree that rarely see the sun exposed to all of that bright light. These are the areas of your tree that are most likely to be affected by sunscald. Calling in a professional to put things right would be the way to go. They’ll also be able to advise you on how to correctly prune that tree in the future.
Summary
Sunscald is more common than many people realise. Fortunately, so long as you regularly give your garden trees a health check, you’ll be able to spot the symptoms before any serious damage is caused.