The poet notices nature through the different elements of nature. These include the crow, the tree and snow. He is able to experience the touch of nature through the dust of snow. A hemlock tree is a poisonous tree that forebodes death. It creates a mood of depression and despair.A crow can be associated with something dark, black, and foreboding. Also,the poet has written about a hemlock tree, which is a poisonous tree. Frost wanted to symbolise the feelings of sadness and regret, which is why he has used a hemlock tree. The crow and the hemlock tree represent sorrow. The dust of snow that is shaken off the hemlock tree by the crow stands for joy that Frost experiences. He has, therefore, used an unconventional tree and bird in order to contrast them with joy in the form of snow.