How does Mao Dun's Praise of Poplar express the author's thoughts and feelings? Why does the author think poplar is an extraordinary tree?

"Praise of Poplar" uses symbolic techniques to grasp the external characteristics of poplars, eulogizes the image of heroic groups who persisted in the war of resistance under the leadership of China * * * Production Party, eulogizes the spirit and will of simplicity, firmness and unity, and expresses the author's reverence and praise for them. The author sings three sighs and sings the word "extraordinary" of poplar repeatedly, which is the basis for the author to express his praise and the clue used by the author to structure the article. Around this clue, the author's "the first sentence is targeted": "Poplar is really extraordinary", which makes readers have a deep impression at the beginning of the article, and the author analyzes it in detail. This paper describes it from three different aspects: the extraordinary growth environment, the extraordinary external form and the extraordinary internal temperament of poplar. From the "beauty of scenery" on which poplar lives to the "beauty of form" of poplar itself, the author further reveals the inherent "beauty" of poplar, and writes all the "extraordinary" essays of poplar from far and near, from the surface to the inside, although the article shrinks from the vast nature to a point in a specific environment, from surface to point; From looking up to seeing a sentry-like poplar in the distance ahead, to describing the trunk, branches, leaves and skins of poplar in close range, this is from far to near; From the standing posture of poplar, it is associated with the simple, strong and enterprising character of poplar, and then from the appearance characteristics of poplar, it is associated with the fighting spirit of the anti-Japanese soldiers and civilians in the north. This is the theme that the author wants to express step by step-poplar is an extraordinary tree.