How is Melinda like the oak tree in her front yard?

Trees and nature serve as a symbol for Melinda throughout Laurie Halse Anderson's novel Speak. In the beginning of the book, Melinda is assigned trees as her object in art class. Throughout the course, she will focus on different types of trees and different methods of drawing them. At first, she is upset to have such a basic object, but as her skill deepens and the types of trees she draws change, she grows and changes as well.
Melinda's first tree renderings are dead or sad trees. She draws ones that are struck by lightning and seem void of life. These trees emulate how Melinda feels; inside she feels dead and weakened from her rape. As she grows stronger and develops her roots, the trees she draws also become stronger and more vibrant.
Her growth also goes beyond just her art class assignments. She branches out and even begins gardening. She nurtures and plants the seeds as she overcomes the trauma of her rape and grows stronger herself.

This looks like a tree, but it is an average, ordinary, everyday, boring tree. Breathe life into it. Make it bend—trees are flexible, so they don’t snap. Scar it, give it a twisted branch—perfect trees don’t exist. Nothing is perfect. Flaws are interesting. Be the tree (chapter 7).

Melinda realizes that trees aren't perfect, but they are strong, and that, like trees she's not perfect. Her trauma has damaged her, but she is still strong.