Asked May 03, 2021, 7:30 PM EDT
Leelanau County Michigan
For white pines to remain green, you need an acidic soil, with pH below 7. pH above 7 can cause yellowing needles. Take a soil test next to the trees.
To get an exact diagnosis, you can consult a certified arborist- www.treesaregood.org
Or you can submit pictures and samples to MSU Plant and Pest Diagnostic lab: https://www.canr.msu.edu/pestid/
Also here are other care steps that, if neglected , can often cause problems with trees:
Check that the trees are not planted too deeply. The base of the trunk where it flares out to the start of the roots should be at the soil line.
Keep mulch pulled back a little so it does not touch the trunk. Otherwise the trunk bark could rot.
Check the soil 3-4 inches down and water slowly when the soil is dry. Trees need supplemental water the first 2-3 years after transplantation. We have had a dry spring so watering is important.
Water evergreens up to when the ground freezes, some time in late October to early November.
If deer or rabbits are present, protect the trees with fencing, cages and trunk wraps from fall to spring, removing the trunk wraps in spring.
Here are references for tree care-