I have a new Nashiki Willow tree - just planted last fall. Why have the inside leaves turned yellow?

Question

The tree is about 6 ft tall. Looked like it was growing new leaves. In one day the leaves toward the center, near the trunk turned yellow.

Answer 1

as a deciduous tree flushes out with new growth the inner leaves will yellow and drop, so it may be normal. but in one day? it may need more water