Environmental history is interdisciplinary. So, you may need to search databases for anthropology, ecology, and so on. Either try an interdisciplinary search like LibrarySearch+ or Scopus, or look for a specialized database listed on our subject guides.
The following links lead to Library of Congress subject heading searches in the CBBcat. These same subject headings can find relevant books in any academic library catalog.
Using the Advanced Search function in CBBcat, you can combine any of these with other terms, such as geographic terms like (Maine OR New England OR Atlantic States), or (History), or kinds of sources like (bibliography OR guidebooks) or (correspondence OR diaries)
Though you will probably start with CBBcat, don't end there.
See United States History: Primary Sources research guide.