The setting of "Birches" is not explicitly given, so we have license, as readers, to use our imagination. Here's one way that we envision the setting, but feel free to come up with your own.
It's a cold New England morning and the snow is almost up to your knee. We might be in Amherst, Massachusetts (where Frost lived), but then again, we might be in another snowy, cold location. A recent ice-storm has left the forest glazed in ice, and the branches of the trees bend under the weight of the ice. The sun has melted the top layer of the snow to the point where it holds your weight for only a second before breaking. Most of the forest animals have either migrated or are hibernating, so you don't see any, and only hear the sounds of the icy tree branches clicking in the wind. If you've never experienced an ice storm, you might want to check out this picture to see the kind of setting Frost was probably picturing.