I planted new sod, now my tree is dying, can anyone help me:confused:

Some trees, they just don't like you messing around near their roots because they have a lot of shallow feeder roots close to the surface. So they will sulk and drop a lot of leaves if you do. Other trees with a deep taproot sort of system don't care. (You didn't say what kind of tree, how big etc.) Often they get over it and new leaves grow back. Or maybe you changed the elevation up or down around the tree when you put down the sod and the roots were shocked or buried a little too deep often they WILLdie from that.

Have you been watering not enough or too much? This could also affect the tree not being happy.

And the tree must be happy. If your tree's unhappy, everybody's unhappy. This is sort of Post Traumatic Stress Disorder of the vegetable variety. Hope you don't have a large, unhappy coconut palm tree with a lot of big heavy coconuts that's mad at you!

Your tree may be experiencing stress and can still rebound. Is this a Maple?

Remember the angry apple tree in the Wizard of OZ? That's all I'm sayin'.

If you have not already done so, and from your dilema it seems you have not, remove a 2-3 foot area of your lawn from around the tree in all directions. Thoroughly water the tree 2-3 inches weekly. Leave the soil bare for a year or two before you spread a 2-3 inch layer of mulch around the tree. It is always best to leave the soil around the base of a tree bare when laying sod. This is because tree roots become accustomed to a certain amount of soil above them and will either suffocate from a sudden addition of soil or dry out from sudden exposure when soil is taken away.