How does the gravel heal a sick tree?
Or were you just heeling them?
Let's here if four homophones!

Apparently you have lived in a cave for most of your adult life... healing in
is a process of burying the rootballs of trees that have been balled and
burlapped, so the roots are protected from the elements. There are a number of
materials that can be used for this, mulch, dirt, sand, peatmoss, sawdust,
gravel, and so on. I was refering to the fact that roots grow through the
gravel quite easily due to the amount of oxygen in the pore spaces that the
gravel forms naturally.

Toad