Thanks y'all. I didn't know how long it might take it to break down so that's what I was aiming for in my question. Long term compost pile it is then. Fibers I could use to improve both the sand & the clay (I have both in different areas) & acid is useful with the sand for sure.
Tara, I'm glad your question got answered in the process. I knew it will not in & of itself kill a tree but the damage lies in shading it out too much. This is why I need to get some (a lot) off the redbud. the former owners planted it directly beneath a huge oak ~~~ a veritable invitation for the moss to transfer to the redbud. The redbud is too large to move at this point (at least by us) so I need to get moss off of it. The pecan trees obviously will not set fruit where it's draped with moss so that's a no brainer.