Hemlock Evergreen Trimming.
Removing the tops of trees will result in the death of the tree, especially evergreens. Unfortunately, "topping" (pruning just the top of a tree to alter it's height) has become a widespread problem over the past few years-throughout this state and surrounding region. Foresters and 'certified' arborists are trying to help educate homeowners/landowners of this ill-advised procedure, but we're unable to keep-up. A tree is genetically engineered to grow a specific height and width, removing the living biomass in the top crown prevents the specimen from gaining nutrients garnered from photosynthesis and caused a slow (sometimes rapid) death. A hemlock will not regrow any needles on old wood. If your trees are too tall, the best thing is to fully remove them at the ground level and replant with another specimen that, at maturity, will grow to the desired height you would like for the area. Check your trees for Woolly Adelgid. These insects are becoming more pronounced in and throughout New Castle County. Here is the US Forest Service site for more information: na.fs.fed.us/spfo/pubs/pest_al/hemlock/hwa05.htm