Arbutus unedo showing signs of stress

I have a newly planted tree, only 4 months ago, showing some signs of stress. Im not sure if it’s too much or too little water.

Any guidance is much appreciated.

 

Looks to me like your tree is probably an Arbutus x reyorum 'Marina' and it burned up this summer because the output from the watering line was not enough for a not-yet-established potted tree planted with a presumably undisturbed potting soil rootball. And planted without enough mulching afterward. In a Mediterranean climate area where April installations will be more or less immediately subject to the commencement of a long and dry growing season - any additional plantings you do there of permanent subjects such as trees, shrubs and herbaceous perennials should be undertaken in autumn instead of spring.