The land wasn't "preserved" for everyone. "Preserving nature" might be too insensitive for a kit series about the Parks.
If you're unfamiliar with what I'm talking about, below are some articles. The last one is from NPS.gov and just after the article is a link to a gallery of images showing segregated facilities (and managers) mentioned in the article. The oldest image is from 1939. The most recent: 1950.
This is the type of stuff they didn't teach me in school, and I wish they had. Maybe y'all learned about it, but I didn't, and I don't want to speak for anyone except myself. Perhaps, if we had learned about this when we were younger, then this mess could have been sorted out already. Then we could be happily and respectfully enjoying state/national parks and monuments without this hanging over us. Thankfully there are people working on solving this, as well as working to rename racist parks/monuments/cities/etc.
Mt Rushmore PBS article (about the broken treaty)
Who should run the US National Parks?
Looking back on Violent Displacement
National Park Service article: "Segregation and Desegregation at Shenandoah National Park"