Spongy ground on one side of oak tree
What is your diagnosis of spongy ground on one side of an older oak tree? It looks like it's pulling out of the ground. Also, is it a months-long process, or years?
Pinellas County Florida
There could be a number of different factors that could be related to this issue. I recommend you send some digital photos (showing the whole tree, the trunk and ground, and any useful closeups showing the soil subsidence) to your local Pinellas County Extension office.
Theri webpage is :http://pinellas.ifas.ufl.edu/contact.shtml