At the beginning of the novel the wood is seen by Duror as his sanctuary from the stresses of his daily life and lowly position.
In Duror's eyes the woods have been defiled by the two brothers, especially Calum. Therefore, to satisfy Duror, the wood needs to be cleansed of evil.
The woods could also be used to demonstrate what was happening in Scottish Highland society at the time. From the point of view of some of the characters, things are slowly changing for the worse. The large estates are no longer places where everyone knows their position in the social order and how to interact with one another.
There is both literal and symbolic significance to the storm, given Calum's 'vision' and the testing of Lady Runcie-Campbell’s morals and character that follows when she throws the lower-class brothers out of the beach hut.
The storm is foreshadowing not only the coming storm of the war as it becomes more violent, but the storm that will rip apart the fabric and social borders of the local society, hopefully creating a better world from the ruins of the old one.
The hut is not fit for human habitation, yet it is where the two brothers have to try and live until they complete their task. This setting serves to emphasise the way Calum especially is thought of as an animal and treated like one.
This is the backdrop of the problems in Duror’s life, which cause him great stress and ultimately push him over the edge into madness.
Many of the locations emphasise the differences between the classes by showing physical aspects such as the furniture or number of rooms. In effect they give each character a place in society which they occupy and, at the time in which the novel is set, cannot aspire to improve. They all 'know their place' in society and live in their own style accordingly.
The Runcie-Campbells have a big house where they never use most of the rooms. Their staff occupy either one small room or a hut lacking the basic sanitation and other facilities that the Runcie-Campbells take for granted.
Lendrick is the local village. While friendly to those who live there, it is distrustful of outsiders. Again setting is important here - the village appears to be behind the times and presents obstacles that its inhabitants need to overcome simply to live there.