HELP! Maple tree problem.

[Al73]

Hi,
I have moved into my new house a couple months ago. One tree on my front yard (maple) started to drop leafs in early July. The bark of the tree is badly damaged and from what I can see, a good part of the tree stem is dead.
Please help me to identify the problem of this maple tree. Does it have chances to recover? If it is a disease, is it dangerous for other trees?

I have a few pictures that hopefully will tell some of you more than my words:
http://picasaweb.google.com/hoiskii/MapleTree#

Also, I am about to cut this tree. Would it be the right thing to do or am I about to kill an "innocent" tree that would live for 100 happy years otherwise?

 

[vaclimber]

That's a pretty badly damaged trunk. Looks like something hit it hard. It also may have scale.

I'd cut it down and plant another tree or three.

I totally agree! You could plant a couple different species and have an equal or greater canopy within a few years. Let a local arborist do the work.

 

[boo]

these trees are also known for root girdling.. looks to have some girdling going on there.