Why do some trees have hollow cavities?



While hiking today, I saw a cut tree that had a large hollow cavity that appeared to run a good portion of the tree’s length. How does this happen? Why do some trees have this while others don’t?

In: Biology

Rot. Usually it’s due to water collecting at a branch crotch where there is a divot in the bark. Other material like leaves and sticks collect then decompose. Added to that is some sort of disease or stress to the tree that keeps it from fighting off the rot. The rot then moves down into the mostly dead heart of the tree where there isn’t replacement of material. Over time it creates a shell of the tree and weakens it until it naturally comes down or is cut. Interestingly you can fill in these rot holes with concrete to keep the water out and keeping the tree together. Isn’t perfect but can extend the life of a big tree

The interior of the trunk or stem of a tree is composed of heartwood or deadwood, as opposed to greenwood AKA sapwood. This is dead tissue which no longer transmits water and nutrients, but only serves to support the tree. This is much the same as the dead calcium skeletons of corals.

Normally the deadwood is surrounded by the living greenwood which completely encloses it. However Injury to the tree such as broken limbs can expose the deadwood to attack by fungi. Wood boring insects can also expose the heartwood to attack by fungi and other *Saporotrophs.*

The fungi consume the wood slowly, causing rot.

This doesn’t directly harm the tree in most cases. But it can weaken it structurally. Decomposition fungi generally don’t harm the living tissue of the tree any more than organisms that cause decay in dead animal corpses will attack living animal cells. However this creates important habitat for wild animals.