How can Ch.7 of Ethan Frome be considered the climax of the novel?

Chapter 7 is generally not identified as the novel's climax since Ethan Frome belongs to modern American literature, but if you were to examine it as such, you should consider Shakespeare's dramatic structure in his tragedies. The dramatic climax of the play occurs in Act III of a Shakespearean tragedy when the tide turns against the hero. In Act IV, the hero struggles valiantly but unsuccessfully to reverse his fortunes, and in Act V he meets his fate and is destroyed.

When viewed in this context, Chapter 7 could be interpreted as the novel's climax because tide turns against Ethan at this point. Zeena returns from seeing the doctor with the news that she has "complications," needs a hired girl to do all her work, and intends to send Mattie away, immediately. This leads to the first quarrel between Zeena and Ethan in their marriage, and it is nearly violent. Ethan is devasted by the idea that he will lose Mattie in his life, and he feels a burning hatred toward Zeena. He refuses to consent. At the end of the chapter, Zeena finds the mended pickle dish. Anger, loss, bitterness, and resentment overwhelm her, all of which she turns upon Mattie. There is no doubt at the conclusion of Chapter 7 that Zeena will put Mattie out of the house. The subject is closed, and Ethan's tragic fate is sealed. When viewed in terms of Shakespeare's structure, Chapter 7 serves as the dramatic climax in this novel, just as Act III contains the dramatic climax in one of his tragedies.

Moreover, the remainder of the novel falls into place as the narrative equivalents of Acts IV and V in one of his dramas. Ethan's fate is sealed, but he struggles valiantly to overturn it. He makes a plan to leave with Mattie, realizes he lacks enough money to support both women, and decides to get the money due him from Hale. This attempt fails, but he struggles on until the "smash-up," which destroys Mattie's body and spirit. In her destruction Ethan's own is realized.