Question
I have 90 two feet tall giant thuja trees. I want to prune them this year to make them more dense and promote deeper roots.How far back do I cut the stingers. I have planted the  trees along a fence line for privacy and a wind break.Thanks Bill

Answer
I would not prune these trees at this time. Pruning does not increase the root or their depth. When they reach the desired height you want the hedge then you can give them a light pruning similar to giving a hair cut, by cutting the ends of the branches with a hedge clipper. Let them grow for now and wait about two years to start the trimming.