The cambium layer, right under the bark, can be very prone to damage.

In any case, in the summer the cambium layer, which is just beneath the bark, often manages to grow back together.

This is one of its many adaptations to fire, which also includes a thick bark to protect the sensitive cambium layer from heat.

Damage the stem at the lowest joints, so that you weaken the cambium layer just below the surface.

There it continues to mine the cambium layer, creating a sinuate "zig-zag" trail down the trunk.

It goes about a quarter-inch in, into the cambium layer of the bark, where the nutrient-transport system of the tree is.

Join the two, ensuring maximum contact of the vascular cambium layers.

This stops the cambium layers from drying out and also prevents the ingress of water into the cleft.

As the tree ages, much of its vascular cambium layer may die.

However, a cambium layer, abnormal mitoses and nuclear pleomorphism is not seen.