I will analyze this poem (NOTHING GOLD CAN STAY") in terms of denotation and connotation, imagery, and figurative language.
             Then I will make an interpretation based on formalistic view.
             There are several words that connote meanings beyond the dictionary meanings. I think "nature" stands for "human nature" because precedes " first" which clearly points to "young age." "First green" stands for "prima vera" in Latin, etymologically speaking. It is talking about springtime of the human nature, youth. By "gold" is meant "precious," "treasure" or "beautiful." So far sounds like "juventud, divino tesoro" of Bequer. He is stating that youth is a treasure. "Hue" denotes (dictionary meaning) any loud outcry or clamor. I think is referring to impulse, strength. "Her hardest hue to hold" must mean that youth's strength is very hard to control. "Early leaf" connotes the first outcome of youth. "Flower" connotes beauty. "Leaf subsides leaf" connotes that next day follows the first day, that time goes on. "Eden" denotes the biblical paradise, where Adam and Eve were happy. It connotes joy and happiness of youth. "Sank" past of "sink" which is to go under the deep of the sea, which in turn recalls darkness, which connotes in turn lack of light, which poetically is lack of joy. It may be referring to sorrow and sadness. "Dawn" denotes morning, which in Latin is "prima luce," meaning first light. Clearly is matching first green and first light, gold and light. That is why at the end dawn, which remembers yellow light, precedes gold, which is yellow too. Both expressions stand somehow for "beginning," which in turn alludes to "youth."
             In terms of imagery, he uses colors like green, gold...