hemlock

Hello, I recently cut down a hemlock (around 12" dbh), split open a section of the base, and saw this white mold-like substance right in the middle of the heartwood. A few feet up the tree, the problem seemed to clear up. I spotted white deposits on the undersides of some needles too, which...

I'm in southeast PA, and I have a row of mature (20+ years old) hemlocks that I want to train to form more of a privacy screen. The branches have gotten too long so they are overhanging the lawn, and lower branches have naturally died off. Is there any way to prune or cut these to stimulate...