| title | ISBN-13 | year of publica- tion | other author(s) |
|---|---|---|---|
| Desert Tree Finder: A Pocket Manual for Identifying Desert Trees | 978-0-912550-07-7 | 1974 | May Theilgaard Watts |
| Pacific Coast Tree Finder: A Pocket Manual for Identifying Pacific Coast Trees | 978-0-912550-27-5 | 2004 | |
| Rocky Mountain Tree Finder | 978-0-912550-29-9 | 2008 | Bridget Watts |
| Rocky Mountain Tree Finder a Manual for Identifying Rocky Mountain Trees | 978-0-912550-05-3 | 1972 | |
| Winter Tree Finder: A Manual for Identifying Deciduous Trees in Winter | 978-0-912550-03-9 | 1970 | May T. Watts |