He's not chopping it down. He's saving it. Those branches were long dead from disease. All plants are like that. By cutting off the damage, you make it possible for the tree to grow again. You watch - by the end of summer, this tree will be the strongest on the block.
Even though Speak was written more than a decade ago, it's just as relevant today. The novel picks up as Melinda begins here freshman year of high school, shortly after she suffered the trauma that haunts her school year. She went to an end of summer party with some friends, had a couple of beers, and is raped by a rising senior. In her terror and confusion, she calls the police, but runs home before they arrive. The police break up the party and Melinda is blamed, becoming an outcast, losing her friends and her support system.
As the novel progresses, we witness Melinda descend into depression, with bouts of PTSD thrown in for good measure. Her grades plummet, she doesn't really make any new friends, she gets in trouble at school, and she stops speaking almost entirely. Her one outlet is her art class, where her year long project is "tree." Her experimentations and dead ends and frustrations with the project mirror her downward spiral; at one low point, she wishes she could sheer away the entire linoleum block in which she's trying to carve a tree and leave nothing behind.
As the year progresses, she begins to recover and find her voice. A friend Melinda thought had abandoned her tentatively reaches back out, helping Melinda find her voice. In a pivotal moment, Melinda adds her rapist's name to the graffiti on the bathroom door under the warning "GUYS TO STAY AWAY FROM." When she returns later, other girls have added to her message with their own experiences with him, agreeing that he's a dangerous creep. It's not hard to draw the parallel to the effect of #metoo and the strength that people draw from realizing that they're not alone.
Speak isn't particularly subtle (Anderson answers Melinda's complaints that Hawthorne's symbolism in The Scarlet Letter is too opaque by hitting you over the head with hers), but Melinda isn't a caricature, either. She isn't a one note depressed high schooler; she has good days and good moments and makes the sardonic observations about her teachers and classmates that you'd expect from a high schooler. And yet it can all come crashing down from a chance encounter with IT (as she names her rapist in the beginning of the book), or even an invitation to a pizza party from a seemingly harmless guy friend.
Despite it's lack of subtlety, I thought Speak had a strong sense of its protagonist's perspective, and I would recommend it (with the caveat that though none of the scenes are exceptionally graphic, there are violent scenes and descriptions of depression and PTSD).