By contrast, spruce, Douglas fir, larch, and Weymouth pine are not native to the forested mountain range. Spruce prefer cool, shady locations and are therefore often found in valleys, hollows and on the lower slopes of hills, while the Douglas fir is found in widely differing locations due to its high adaptability. The sweet chestnut was not originally an indigenous tree species, but was naturalized by the Romans in the area of the present-day Palatinate. Since it prefers a mild climate (see temperature) like the grape vine it is found on the eastern edge of the Palatinate Forest, the Haardt, in pure or nearly monocultures and represents about 4 percent of the forest area there.