Litterst

Over the last 70 years, NPS has tracked a temperature increase of about 2.2 degrees on the Tidal Basin, which is ringed with cherry trees, Litterst said.

So when we have to replant, a lot of times we’re able to get a genetic match of some of those early trees,” said Litterst.

Mike Litterst, chief spokesman for the National Park Service, said the nation’s more than 400 parks are reopening on a rolling schedule.