What Causes Crown Shyness? – Canopy Disengagement

Also called canopy disengagement, canopy shyness, and intercrown spacing, crown shyness is mainly observed in areas with clustered trees.

You’re likely reading this because you’ve recently observed or encountered such formations. This article provides all the answers you seek regarding canopy disengagement.

Tree Crown Shyness

Certain observable natural phenomena can be fascinating for observers, with lots of questions arising about the causes and if these are due to underlying problems.

One of these phenomena is crown shyness. You might have come across pictures where tree crowns seem to avoid touching.

  • What is Crown Shyness?

Canopy shyness is a condition that can result between trees of the same species, trees of different species, and within the same tree.

Now crown shyness isn’t very common. That is why you probably haven’t seen one yourself. While that is true, it doesn’t negate the condition’s existence.

Crown shyness has been noticed in tree species like the Japanese larch, black mangrove tree, eucalyptus, Sitka spruce, Lodgepole pine, and camphor trees.

So, is crown shyness in trees a bad thing? It gets a little more interesting because many theories have been given for its occurrence.

Causes of Crown Shyness in Trees

So far, no definite reason for canopy disengagement in trees has been given.

While there are many theories about the possible causes, some of those that sound reasonable include tree injury, the action of pests and diseases, and photosynthesis.

Without further explanation, the possible causes mentioned will make little sense.

To avoid that, let’s briefly look at each of those mentioned to understand what crown shyness in trees is all about.

i. Tree Injury

The theory on tree injury as a likely reason for crown shyness assumes that spacing around the crown is a protective measure by trees to minimize damage, especially when blown or swayed by the wind.

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The spacing offers a buffer zone where tree limbs don’t have to brush or collide with each other.

Such collisions result in broken branches or injuries. This interferes with the average growth processes of trees. So in a bid to adapt, canopy disengagement between trees occurs, thus making for fewer cases of injuries among trees.

ii. Pest Action & Diseases

Certain tree pests are known to spread to other trees around rapidly.

While some will spread through the root systems, others mainly rely on the bridge formed by contact of tree leaves and branches with neighboring trees.

With crown shyness, it’s assumed that trees form a defensive system to limit the rate of spread of pest attacks.

Aside from pests, bacterial and fungal diseases affecting trees also spread similarly. Again, canopy disengagement makes it challenging to quickly spread such pests and diseases to neighboring trees.

While there may be holes in this theory, it still sounds plausible.

iii. Photosynthesis

The third theory or explanation for crown shyness is attributed to the need for optimal light penetration for effective photosynthesis.

Trees require sunlight for photosynthesis and do best when light penetrates the canopy. It’s believed that the spaces created by crown shyness help with that.

In other words, disengagement allows for better light penetration into the tree canopy.

As trees grow in the direction of light, any obstruction due to shade from neighboring trees makes them redirect their growth to a more favorable direction.

So, photosynthesis could contribute to crown shyness conditions in trees.

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Possible Explanations for Crown Shyness

Apart from the theories discussed above, others point to a “truce” between competitors (trees) with limited resources.

Here, the goal is to maximize resource collection while avoiding unhealthy competition, which doesn’t benefit all. This theory further supports some of those mentioned above.

Where to See Crown Shyness

Most people living in urban centers are unlikely to have seen or noticed crown disengagement in trees.

That is because it doesn’t happen all the time, and when it does happen, it mainly occurs around tropical forests. These forests tend to have flatter canopies which provide the right conditions for crown shyness.

With this fact, it’s unlikely that you’ll find or notice crown shyness around temperate regions or if you live in an urban center.

Is there a Definite Reason for Crown Shyness?

As mentioned earlier, we pointed out that theories mostly abound for this natural phenomenon.

While these theories do not offer definite explanations or answers, they’re still discussed or included here because they sound reasonable.

The many unreasonable theories that abound haven’t been included.

For an in-depth discussion on crown shyness and its causes, you might want to discuss or seek the opinion of an arborist. These plant experts can offer reliable information on the grounds of crown shyness.

You might also want to research the cause thoroughly o understand the reasons behind this phenomenon.

Most people are intrigued by crown shyness and wonder if pictures have been photo-shopped or actual images of tree formations. So far, we’ve seen several explanations about crown disengagement.

Discussing with an expert may give you a better understanding of underlying causes.

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