We have a tall pine tree (25-30' tall?) that I noticed this spring is turning brown. I've only really noticed it in the last two weeks, but it's really pronounced. Not sure when it started.

I spoke with the folks at Tagawa Gardens about it and showed them the same photos I've uploaded here. They're pretty sure it's environmental in nature and not caused by some predatory bug/pest. They're having me take readings with a water meter surrounding the tree to assess whether the soil is over or under-watered. We turned on our sprinklers 3-4 weeks ago, which might have been a little late, but otherwise, we haven't done anything differently this spring watering-wise than we have since we moved in in 2016. 

The base of the tree in the rocks doesn't get any direct watering, but the grass areas do from the our sprinkler system and our neighbor's. 

I'd love to find a way to nurse the tree back to good health, but I'm worried it's unsalvageable at this point. 

Can you help?

Thank you!

Brian Clark