Tour 931
Ranger
I believe they use satellites now.I seen to remember a news story within the last few years that mentioned that many of the human observers who manned the towers have been replaced by electronic sensors that are better at spotting the fires than the human eye....and cost less to maintain.
My 100 year old neighbor knew the guy that maintained the tower. He lived less than a mile away and only went to it during storms. In Washington State I’ve hiked to many of them as there they are very remote. Most of them were college students and manned them in the summer. Most were resupplied by helicopter as most had no roads to them.