Ernst made many different works based on the forest and all have common elements: a dense wall of tall trees, a perfect circle representing the rings of light from the setting sun, and -if you look more closely- what appears to be a bird. Of course, these visual elements only appeared gradually to Max Ernst himself, as his technique involved first layering thick oil paint over a prepared canvas, and then in turn pressing this canvas over different quotidian objects such as wire mesh, shirt buttons, wire mesh, fish bones, and other detritus.
From here he would scrape the paint off, and the contact from the objects laid underneath would impress upon the paint creating different forms and textures. As he would go about scraping away the paint, Max Ernst would interpret the emergent forms. This is what is known Ernst's trademark Grattage technique, with this word being the French word for "scraping".
La Foret or The Forest is one of a number in a series of grattage generated paintings that were inspired by the german forest, particularly a forest south of Cologne that had fascinated and frightened Max Ernst when he first came upon it as a three year old child. This particular work dates to 1927 or perhaps 1928, which places it firmly in his first French period. In the work we see that the sun is obscured in large part by tall trees and dense foliage. The overall sensation is one of forboding; the forest is seem as impenetrable and as if it were harboring great secrets.
In fact, Max Ernst had had an essay published in 1934 titled Les Mysteres de la Foret or "The Mysterious of the Forest" in Minotaure, the magazine founded by Albert Skira and E. Teriade and printed in Paris in the 1930s that was central to the surrealist movement. In this essay, Ernst described the forests as being savage and impenetrable among other adjectives.