Before the herbicides the blacktail population exploded anywhere there was continually ongoing logging operations. I remember the early to mid 90s up on the Yacolt Burn. Weyerhauser was logging like crazy, as the clearcuts started to mature, the deer population exploded. It was nothing to see 150 deer in a day if you were actually hunting. I had many years, that my season was less than 2 hours long. Had my buck in the truck and headed home. The drop in population in the NF is caused by the logging moratorium in Gifford Pinchot. There used to be tons of deer all along the N. Fork of the Lewis, up around St. Helens and the surrounding areas. Still are for the most part, just takes a bit more hunting to find the good ones.