Hello,

This sounds like it could be white pine needle disease (WPND).  This disease is a caused by several fungal pathogens, which makes treatment difficult and not very effective. Once trees start experiencing symptoms like this, the stress of not having all of their needles producing food for the tree makes them vulnerable to other pests and diseases. It is recommended that white pine are planted where there is good air circulation around the tree, but that is no guarantee that the tree will stay healthy.

 You may want to consider consulting an ISA-certified arborist to see if the trees are able to be saved.  To find one in your area, go to Find an Arborist (treesaregood.org).  Cutting off the lower boughs will probably not do much to control what is going on with these trees.  Here is some more information on the types of problems white pines are having:

Landscape: Dieback of Eastern White Pine | UMass Center for Agriculture, Food and the Environment

I hope this answers your questions. Thank you for contacting Ask Extension.

Ruth