Hilton Falls as Pahvo Forest
Michael, Saru, and Ash travel through the forest towards the antenna but get sidetracked by a strange blue haze which they follow to a small building.
Source: Memory Alpha
“Si Vis Pacem, Para Bellum” Filming Locations
Star Trek: Discovery episode “Si Vis Pacem, Para Bellum” was filmed in Canada
Kelso Conservation Area as Pahvo Ridge
Michael works on the antenna to send the signal to the Discovery but Saru arrives to try to stop her.
Source: Memory Alpha