About a week ago, there was a discussion regarding Pine trees turning brown
and dying. I was not the original OP, however was having the same problem
with a 30/40 foot pine. OP was in Baltimore and I live in Texas, so water
and/or climate didn't seem to have any commonality.

Today (09/23), I had a tree removal service out to cut down my tree. While
it was on the ground, about 20 feet up, we discovered more fresh holes; and
inside there were numerous tiny worms and bugs. We crossed them out in a
Book and positive results were "Pine Bark Beetles"! How or where they
originated is somewhat of a mystery, but end result is they went with the
cut up tree to a burn pile!

Thanks to all who responded..

--
Bill