Why is it so scary in the forest at night?

YYY: I served in the army in Transbayalya, on the border with Mongolia. Served at a point, a point two kilometers from a small town. The city is militarized - the military more than the civilian, as a result, the city is full of patrols, officers, and the local soldiers were disliked. When I went out of the car, at night I went out of the city into the forest, then in the night forest, I was captured by a sense of complete security.