We have a fir tree in the back yard approximately 75 feet tall. Over the past few months there have been about 4 branches that have broken off, where the break is something like 10+ inches away from the trunk and not a clean break. These branches are about 10 feet or so in length, maybe 7" diameter. This tree was pruned by professionals last October, and assessed by an arborist as healthy. I realize the snow was a contributing factor, and yesterday the wind. But this doesn't seem right for a young fir. Any ideas, suggestions? Is this normal or is there something making this tree brittle? Thanks.