What animals needed the truffula trees?

The Truffula Trees were a creation by Dr. Seuss in his book "The Lorax." In the story, the only animal explicitly stated to need the Truffula Trees is the Swomee-Swans.

The Swomee-Swans used the Truffula tufts to build their nests and raise their young.

While other animals are mentioned in the story, it's not explicitly stated that they rely on the Truffula Trees for survival.