While Germany is generally thought of as a pretty heavily forested country today, there used to be far more woodland in the country. This map shows the areas of Germany that were predominantly covered in forests around 50 A.D. on the left. You can see present-day Germany on the right and what little forest still remains in the country. At least what little forest still remains on a large scale.
There also appear to be fairly few historical areas in Germany that didn't harbor forests, as say compared to a place like the U.S., where the central part of the country has always been made up of plains.