Hello Tom,

Green needles dropping suddenly could be from a few things.

-Check if the soil is actually receiving enough moisture or too much water.. Carefully dig down about six inches near the roots, below any mulch or landscape fabric. Is the soil moist? Is the soil soaking wet and roots are rotting? If too dry, remove mulch and landscape fabric and water the tree. If too wet, determine why and prevent the area from receiving too much water in the root zone( by regrading, building a berm, redirecting downspouts, or fixing a leaky underground sprinkler for example).

-An overspray, granular application  or drifting of herbicide ( such as lawn weed killer) could have reached the tree and caused needles to drop. The branches might recover from this in time

-Damage (mechanical injury ot animal gnawing) or diseased areas (cankers or rots) on the trunk, limbs or roots could have interrupted the flow of water to the branches that are affected, causing needles to drop.

I see an injury at the base of the trunk that appears to have been there some time. This could be affecting certain branches, causing them to not receive enough water. Look for other damage along the trunk and branches.

Here are beat practices for your trees:

Be sure a circle about 4-5 inches all the way around the trunk is bare so that mulch does not rest against the trunk. Mulch no deeper than 2-3 inches over the root zone and use no landscape fabric there. Correct any grading so that soil does not remain flooded, or too dry. Water deeply every 14 days  if weather becomes dry and no rain is expected.

You might consult a certifed arborist who can check the tree over in person and give you a plant health care plan. You can search for certified arborists at this site— http://www.treesaregood.org

You may also consult the MSU Plant and Pest Diagnostic lab. They can review your pictures if you email them along with the plant’s history of care— <personal data hidden>

If the lab needs a sample for diagnosis, there is a fee for that service. Their website has instructions for submitting samples- https://www.canr.msu.edu/pestid/