Dying (if not dead) oak

Hi all,
I have a large oak tree (about 40ft tall, 2-3ft diameter) in my back yard. Last summer the cicada really did a number on it, killing about 60-70% of the leaves at that time. This summer the killed 60% never came back, and the tree wasn't looking that great. I Just came back from vacation to find that huge chuncks on the bark at the base have fallen off (like half of it on the base), with cracks running up the sides (presumably telling me that the bark is going to fall off). Another interesting fact is that I have really let the grass grow up around the base of the tree, having weed wacked it only once this summer. Poking around the base of the tree it appears that there are ants and other nasty things living in the base.
My question(s) is(are): I am I the tree killer, or those noisy cicada? Would the lack of maintance of the grass with excesive build up cause the tree to rot? Can Should I dig back to clear the roots? Is there any hope? Can grass build up cause the base of a tree to rot?
Thanks for any/all input.
don
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@gmail.com wrote:

From your description of it there doesn't seem to be much hope for it -- the insects know a good thing when they see it and a good thing for them isn't a good thing for the tree. I have no way of telling about your tree but there is a condition on both the east and west coasts called "sudden oak death" and that could be what got yours. If you google for that term you might be able to make a decision. Trees are able to go on for quite a long time giving no external clues while the interior of the trunk rots until one day all systems simply fail.
Year before last I had a relatively large oak do exactly the same thing as yours in my side yard. The only positive is that oak makes pretty good firewood at least if you harvest it before the rot and insects get to far into their jobs.
--
John McGaw
[Knoxville, TN, USA]
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
This is a test
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.