Does anyone know what makes leaves on a japanese magnolia tree turn brown?

Question

i have a japanese magnolia tree that i planted. I'm new to gardening especially trees. I have started seeing the leaves of the tree turn all brown and brittle like they are dying. Some of the leaves have brown spots. Am i doing something wrong? I water it , give it plant food, and have sprayed for fungi and insects but nothing works.

Answer 1

i think it is because of sulpher in the air