I have two coniferous larch trees that the needles are turning brown and falling off, even though they have healthy new growth on each branch. I cannot figure out why as I have two very close neighbors whose larch trees look great. I planted these trees about four yrs ago. Sorry no photos!
Browning of Larch Needles in Summer
Certified GKH Gardening Expert
There can be a few reasons for browning of Larch Tree needles; from pests to a few diseases.
It may take further inspections to determine the issue.
These links may help with diagnosis.
I would also suggest talking with your County Extension Office to see if any regional issues are known.
This link will help you locate your nearest office.