Firelookout.com makes mention of this abandoned 1942 tower possibly located near the Ninety-first Division Prairie. I hope to get more information but for now, I couldn’t find any evidence of a lookout existing in the vicinity of where it was located on the website. Nor could I find any staff that had any knowledge of this lookout or any pictures around the forestry building. The 10th Field Artillery Bluff offers an excellent view of the Ninety-first Division Prairie so I wouldn't be surprised if one certainly existed on the bluff.
WillhiteWeb.com - Washington Fire Lookouts
One of many range lookouts on the Ninety-first Division Prairie
Ninety-first Division Prairie from the 10th Field Artillery Bluff