Hello everyone. My four year old oak tree in my backyard (in Arkansas) has some problems this year. The leaves are much thinner than usual and there are lots of brown leaves and branches. Some of the small branches (new growth) will have one or two pretty green leaves, and the rest are brown. The attached picture (yes, I know it's not very good due to glare) is AFTER i removed several of the dead leaves. There were enough dead leaves this morning to fill up a lawn and leaf garbage bag.

Also I spotted this fungus at the base of the tree which I dug up today. There was another oak planted nearby before that was hit by lightning and this one took its place.

There are more pictures:
http://i.imgur.com/wAOgM6Y.jpg
http://i.imgur.com/1LY3se4.jpg
http://i.imgur.com/ZmcdHwf.jpg
http://i.imgur.com/Prl7EJS.jpg
http://i.imgur.com/h2XygrJ.jpg

Please help me figure out what is wrong with this tree! Thanks!!