What would cause the leaves to turn brown right after they first sprout in spring?
Certified GKH Gardening Expert
You will need to further examine the tree; trunk, bark, branches and leaves.
Look for signs of canker, insects or fungus.
Environmental changes could cause the browning of leaves, such as a drop in temperature but stone fruits are susceptible to several diseases
that may involve leaves turning brown.
Here are some links with more information.