This tree started to leaf this spring, but the leaves curled up and dropped off. The tree seems to still be alive but no leaves. What is the problem?
I suspect you have some type of insect infestation. I would inspect your tree closely for insects, specifically aphids. For more information on aphids, please visit the following link:
https://www.gardeningknowhow.com/plant-problems/pests/insects/homemade-aphid-control.htm
Happy gardening!