Why do you think the poet does not mention “the departure of the forest from the house” in her letters? (Could it be that we are often silent about important happenings that are so unexpected that they embarrass us?
The poet hardly mentions about the departure of the forest from the house in her letters because it is humans, who did not care for nature in the first place. So, maybe, the poet now thinks that nobody would be interested in knowing about the efforts that the trees are making in order to set themselves free.