We have a number of Eastern White Pines on our property. Every fall, the White Pine will begin to lose its 2nd year needles. This is a natural occurrence that the trees experience every fall.
I have experienced at other facilities a needle drop during the spring which normally occurs because of some type of environmental stress that effects the growth of the tree and causes the needles to drop early. Disease, insects, and or large swings in temperature or moisture that occur from time to time create this phenomenon.
The needles at the tip of the branch are this years new growth.
For additional information on the Eastern White Pine, check out the link below.