In World War I, Croonaert Wood was one of the sites used by German units to defend the area around the Ypres Salient.
The Germans built a defensive complex of trenches, dugouts and bunkers on the slightly elevated landscape, from which artillery observers had an excellent view of the ground around Wijtschate and Ypres.
The area was the site of extensive mining activity by both German and British units during the war.
Before the Battle of Messines, the tunnelling companies of the Royal Engineers placed a large mine around the German strongpoint Günther, not far from the Bayernwald trenches.
It consisted of three chambers (Hollandscheschur Farm 1, 2, 3) which were loaded with a combined charge of 66,600 pounds (30,200 kg) of ammonal.