What makes the sight from the coppice gate so depressing in "The Darkling Thrush"?

The view from the coppice gate is so depressing because it is a dreary winter day in the late afternoon (the speaker refers to this time as the "weakening eye of day") as the sun is beginning to go down. Everything looks gray and desolate. It is cold, and the frost covering the landscape is a ghostly "spectre" gray.
Bine stems—the branches of bushes—seem to score or scratch they sky. We can imagine them as dead and spindly this time of year. They look like broken lyre strings against the sky (a lyre is an instrument similar to a guitar).
No people populate this chilly, bleak, desolate landscape, adding to the depressing feeling. The speaker tells us that they are huddled around their fires inside. This conveys the idea that this is not a day anyone would want to be outside.