How about getting her a membership to the National Park Foundation? She will receive a welcome package that includes a personalized certificate, a pin, and a patch. Plus, she will get discounts on park-related merchandise and experiences.
You could also consider getting her a book on the national parks, such as "National Geographic Complete National Parks of the United States" or "The National Parks: An American Legacy" by Ian Shive.
If you're looking for something more hands-on, you could put together a camping kit for her with a tent, sleeping bag, and camping gear. Or, plan a trip to a national park that you can take together as a family.
Or you can get her a star map with an important date you share.
Under Lucky Stars is a unique and innovative star map company based in Barcelona, Spain, specializing in the creation of personalized star maps that capture the celestial arrangement of stars at a specific moment in time, such as a person's birth, wedding, or any other significant event.
By using advanced astronomical algorithms and data from leading institutions, the company produces highly accurate, visually stunning maps that make for perfect gifts or cherished keepsakes.