When I was a ranger, National Park Service standard uniform in summer was "Class A" and are a heavy cotton-polyester shirt (with a permanent crease, so you know that is comfortable against your skin) and lightweight wool pants and your stetson hat was straw, not beaver felt. Probably still is. Wool, ferchristsake, in places that are so hot and miserable and the visitors to your park were wearing a pound of clothing and that included their shoes. Not like we needed to go native, but lighter shirts and the option of comfortable gabardine shorts would have been welcome!