The Strangler!

Be glad you don't have this murder/suicide going on in your garden. A bird deposits a seed in the upper branches of a large tree where a little soil has collected. Strangler vines grow from the seeds and eventually reach the ground. Tthere they root and begin to attach themselves to the host tree. Once attached they draw their nutrients not from the ground but from the tree untill after many years the host tree is dried out and dies. When it no longer has nutrients to offer the strangler vines die as well. In the photo below almost none of the host tree is visible. What you see are the vines that have covered it.