When Ted Wells’ fourth-grade class read Dr. Suess’s The Lorax, in which the Lorax character “speaks for the trees,” his students were inspired to do what they could to prevent a Hollywood studio from watering down Dr. Seuss’s environmental message.

Wells’ Park School class in Brookline, Mass., helped convince University Pictures, which is releasing a Lorax movie in March, to green-up the marketing of its film to reflect the book’s theme. The students started an online petition that collected more than 56,000 signatures. Movie star Edward Norton tweeted about the petition, and Mother Jones and Grist also ran articles about the students’ project.

Wells updated the petition on Thursday: “They’ve changed their website almost exactly as my class requested!! Same visual, same link!!” The class had asked that the website have a Lorax Tip button that let viewers see a list of ways to help the planet. Universal also told Wells it was putting other environmental initiatives in place.

Wells said his students celebrated with a dance party during snack break. He also reiterated the famous quote from The Lorax: “Unless someone like you cares a whole awful lot, nothing is going to get better. It’s not.”