Large Arborvitae Bushes Have Dead Centers

Question From: A. Anderson - PENNSYLVANIA
Q: Moved in a house where we have a row of arborvitae that appear to have never been cared for. The inside of the bushes are a tangle of dry dead branches that snap off easily. I've started cleaning the bushes out and I've cut many of these innner branches back to the trunk. The outer branches have foliage that is green and looking healthy but now the green branches are sort of a shell to an empty inner bush which might be problematic when winter hits. For the next few seasons, should I prune the outer "shell" carefully to encourage growth in the interior? Will that work? Removing the dead branches won't hurt the bush, will it? They are large bushes and not sure if I can protect them for winter snow. Any ideas?
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A: Yes, get an onsite inspection from a certified arborist. To find one in your area, go to and enter your zip-code.   Best Nancy