Q.Dead White Pine tree.
Why did one pine tree die the one next to it is healthy? Both were planted as saplings and are now 15′ tall. Suddenly over last winter one died. It’s completely brown, yet 10 feet away its twin is healthy growing? I can see no wounds or sap on the bark. No exposure to road salt. 50 feet away are huge healthy pines.
Trees can die off for different reasons, environment, pests and disease.
Here are some links that may help you.