Ontario white pine
I have three white pines on my property. The tree that is at the top of a backyard hill (granite) has turned yellow almost overnight. It is the only tree doing that. The other two are on lower ground and are still green. I understand they shed somewhat in the fall. The site: https://www.gardeningknowhow.com/search/?q=white%20pine%20needles%20turning%20yellow ...tells me it could be for lack of water and in this area (just north of Kingston ON) it has been dry for about three weeks now after a very wet summer. Thank you.
Certified GKH Gardening Expert
Yes, I do believe this is the most likely situation. It seemed to be getting enough water until recently. If you can try to get extra water up to the tree.