What causes the leaves to turn reddish yellow color and fall off? It's not leaf curl.
Certified GKH Gardening Expert
It might be a nitrogen deficiency, but it would have to be pretty severe to cause that kind of damage. Root rot would be another possibility, but that would be unusual for this kind of tree. I would also check for pests. They will normally be found on the underside of the leaves or in joints where the stems and branches meet.