Brown patches on conifer tree

I have a conifer tree that started getting brown patches last year and these are getting larger and larger. What could have caused this? My garden is quite exposed. Also, last summer, I made a change to the area where that tree is planted: the whole bed used to be covered in gravel and I removed the gravel and moved the ground in order to add more plants. Could this have disturbed the tree?I don’t know the name of the tree but its normal colour is pale green/golden.