These different habitats can be found in a relatively small area in the Mattheiser Wald nature reserve, which was a military restricted area for much of the 20th century. The German Wehrmacht and later the French army used the area in the southeast of Trier as military training area. Civilians were forbidden to enter the biotope on their doorstep for decades. During artillery exercises in the barracks Castelnau served the opposite forest as a target area. A network of wide armored roads was created. Plastic shells of practice grenades are still found throughout the area.