Landscapes of Frederick are filled with symbols. The phases of the moon, the times of the day, architectural forms and, of course, the trees – all this could acquire symbolic significance in his works. The artist often transmitted the finiteness and short duration of human existence with the help of withered trees and broken branches – as, for example, in “Landscape with a withered tree”, ca. 1798, in which the silhouette of the dead tree echoes with the ruins in the background. In the “Ancient burial under the snow,” ca. 1807 withered trees surround the ancient tomb.