"dragons plant no trees" gets thrown around a lot as fact, but i think the veracity of that claim is still up for debate in the books. because dany (like bran and jon and many others) is a narrative symbol of hope and rebirth within the series because of her connection to dragons and fire, not in spite of it. this is because dragons in asoiaf have a much more expansive narrative function than simply 'nuke metaphor'. the 'exclusively weapons of war' image they have acquired breaks down immediately if you recall that the first thing dany does with them is begin dismantling an unjust status quo. she rallies the unsullied at the gates of astapor with cries of dracarys! dracarys! freedom! <- dragons as a symbol of hope and freedom for the persecuted. and obviously they've been built up as an oppositional force against the others. we're told when the last dragon died summers became shorter. in that respect the dragons, or more specifically, fire which is warmth which is passion—very much embodies life against the numbing, deadening threat of eternal winter that the others represent. but fire also consumes, which simultaneously makes dragons agents of destruction, or as adwd shows: the monsters who eat little girls and leave behind their bones. but when dany found herself chained to a false peace which effectively undid her cause in meereen, it was the dragon that rescued her and reignited her fire to fight back—which is to say that dragons represent a wealth of contradictions within the text and this is likely something grrm means to parallel with the others to some extent, by questioning their apparent narrative role as the one true evil. because i doubt the series is gearing up towards a spectacle-esque battle wherein our heroes get to practice righteous, easy violence on a monolithic army of monsters. that feels like it would undo a lot of asoiaf's preoccupation with investigating violence against socially acceptable targets, even if said target is ice sidhe. and this binary between a one true good and a one true evil, i.e. melisandre's philosophy ("if half an onion is black with rot, it is a rotten onion. a man is good or he is evil.") is not something the story takes as given.
instead there's this exchange between bran, jojen, and meera in asos: "but you just said you hated them." / "why can't it be both?" / because they're different. like night and day, or ice and fire." / "if ice can burn. then love and hate can mate."—and i think it's talking about reconciling two conflicting ideas. because the dream of an eternal summer is just as unsustainable as the threat of eternal winter. i think the battle for dawn is more about questions of seasonal harmony. the first line from agot's summary says, "long ago, in a time forgotten, a preternatural event threw the seasons out of balance", so it's not totally out of question for the series to end with that seasonal balance restored once more. and that question of balance and how it can be achieved then works as a metaphor for a bunch of other things. because asoiaf at its core is very interested in exploring big contradictions, like love and duty? how do you keep all your oaths without betraying someone you love? how can one hope for a just, rightful ruler in a world where the systems in place can never allow such a thing? how do dragons plant trees?
you cannot frame dany's arc as a binary choice between planting trees or embracing (dragon)fire. because the fire is hers, it is a part of her, that's who she is. and her character has always existed outside of rigid dichotomies. at the end of agot she had two options, resign herself to a life of seclusion as a widow or die with the last of her family in that pyre, instead she performed a miracle. presently, i think grrm means to explore necessary, revolutionary violence with her arc because you cannot deal with institutional slavery by simply negotiating with slavers like she does in adwd. and the consequences thereof because she's also been set up to be more reckless with dragonfire in the future. but i think there will be an eventual reconciliation there, between her dreams "to plant trees and watch them grow." and her role as the mother of dragons, as a revolutionary figure. because if ice can burn, then maybe dragons can plant trees. they'll learn how to.