Different varieties of trees have different levels of resistance to temperature, and disease. Knowing the nursery origins of the trees may solve the mystery outright. If the tree is from a nursery outside of the prairies there is a good chance that the problem is because the tree is not winter hardy, even if the others from the same species thrive in our conditions. Another consideration in this step is to determine the approximate age of the tree and when it was planted. Just as do people, trees go through a period of juvenility, before maturity.
Trees also go through a period of transplant shock.
The first three years after a tree has been planted are the most critical time for proper care. Young trees are less able to with stand stress than established trees. Knowing what is abnormal requires that one knows what is normal. An example of this is that is normal for a spruce tree to have no needles in the centre of the tree. If one doesn't know what is normal, compare the tree to others of the same species growing nearby.