Definitely not balsam firs. Balsam firs have very soft flat needles if you were to stoke a branch. The white spruce will be stiff and prickly with round needles. Balsam also keeps smooth bark while white spruce develops scaly bark. I would say with 80% certainty they would most likely be white spruce. If they were norways they would have likely been browsed pretty hard and never allowed to get that big. They look identical to the white spruce I pulled out from under the power lines by me. Crush some needles with your fingertips and stroke a few larger branches. If they smell like shit and prick you its most likely a white spruce.