A Terrible Toll
By 1917, volunteer recruits for the Infantry battalions were no longer sufficient to fill the depleted front ranks, and the Canadian government was already considering Conscription to make up the difference. That encouraged enlistments in the Forestry Corps: working behind the frontlines, it was considered a "safer" way to serve.
Foresters did suffer casualties, though. Their work was dangerous; some were injured by saws, equipment, and falling trees. Their above-average age contributed to fatigue, muscle and joint injuries, and "general debility." More forward units were shelled during German air raids.
Even though the Foresters were not in the thick of the fighting, some also suffered from "shell shock" - what we now recognize as PTSD.