In the first stanza fog is personified. This suggests winter is near because nature feels the effects of it. The second line contains a metaphor. Therefore they are safe from hunters until the fog disappears. The second stanza describes cold images.
Poplars are a type of tree with small leaves.
The wind also rustles the crow, so often associated with cornfields. The third stanza describes a fishhawk, or type of hawk, circling a pond, perhaps looking for food. In the fourth stanza October is personified as burning on cornleaves. The effects of this month kill, or burn, off the green of plants and change them into colors. Pickers and wheels suggest the activity of harvest, which was characteristic this time of year.