Almost certain to be a water/root issue of one type or another.

Was it container grown, B&B, or what?

I'm not familiar with your climate, but it sounds like you may have jumped the gun by planting before leaf fall. Why did you pick now to plant? What's your weather like now?

How did you use the compost? I hope you're not saying you used that as an amendment. If so, this could be a source of drainage problems and may result in poor root system formation. Give us more detail about how you used the compost.

Tell us more about how you planted the tree (planting depth, soil amendment, mulching, etc).

How have you been checking soil moisture levels? Have you been monitoring moisture levels both around and in the rootball?