More willow is a term that refers to the expansion of the willow tree species in a certain area. Synonyms for this term could include the growth of willow, the spreading of willow trees, the multiplication of willow plants, and the extension of willow coverage. The usage of these synonyms could vary depending on the context of the sentence or paragraph. For example, the phrase "the growth of willow" might be used to describe the increase in size of a single willow tree, while "the multiplication of willow plants" could refer to the growth of numerous willow saplings in a certain location. Ultimately, the use of synonyms can help to add clarity and variety to any written or spoken communication.