"Thinning" of a maple tree

[doctorragamuffin]

[align=left]Hey all, long time no post. . .[/align]
[align=left]I had these three maple trees in my front yard, probably about 8 or 10 years old. . .one stunted, thinned, and died a few years ago -- I cut it down.* Now one of the two remaining (the next one down the line from the initial one) is also thinning -- if you look at the canopy you can see the sky on the other side -- the canopy is stunting or thinning or whatever you can call it.* [/align]
[align=left]*[/align]
[align=left]** I can't come up with any reason -- the FIRST one just HAPPENED to be the closest to an underground water or gas line, but I can't see that being a cause?* [/align]
[align=left]*** Any BEGINNINGS of an idea as to what may be going on here?[/align]
[align=left]*** Thanks in advance...[/align]
[align=left]Dave [/align]
[align=left]Murfreesboro, TN[/align]

[Newt]

Hi Dave!!*

Long time no 'see'.* Hope all is well in your corner of the world.* :)

My guess, without any further info, would be Verticillium wilt or maybe Armillaria root rot.* Take a look here to see if any of these symptoms fit.* You'll have to scroll down to the bottom of the page and click on the different tree parts. *
http://maple.dnr.cornell.edu/pubs/diseases/diseases.htm

Newt