You can put a price on people’s access to nature, and for states, it’s a pretty good deal. A new study uses selfies taken on conserved lands, like state parks, to calculate more precise visitor rates than parks services typically record, finding that nature preserves provide a pretty good boost to the tourist economy, as Popular Science reports. 

A study led by the University of Vermont’s Laura Sonter (who’s taking the selfie in the image above) examined geo-tagged photos uploaded to Flickr, and compared them to maps of conserved lands in Vermont created by the Nature Conservancy. Using photos from 2007 to 2014, the researchers counted the number of people each day who uploaded at least one photo from the specified areas. The research is published in PLOS ONE

From the selfies they found on Flickr, the researchers estimate that conserved lands saw about 3.6 million visits a year—29.1 million in total. At least 5.1 million visitors were from in-state, while 6.3 million came from outside Vermont. 

The researchers used data on average tourist trip expenditures to extrapolate the estimated income that people seeking out forest recreation areas like state parks brought into Vermont’s tourism department. The average in-state visitor spent $82 a day, while the average out-of-state visitor spent $59, for an estimated $1.8 billion in state revenue over those eight years, due to visits to conserved lands. 

Using this method, the researchers also hypothesize that you can calculate relative values of different aspects of conserved lands to visitors, like how big the size of the park is, whether there’s opportunity for snow sports or swimming, and the size and proximity to surrounding towns. 

The study’s method of using Flickr photos to track park visitors is especially useful because most parks and preserves don’t keep accurate counts of people coming and going year-round. Not everyone who visits is going to take a photo, and certainly not everyone is going to upload it to Flickr and tag it with the location, but the method at least provides a way to get an estimated head count. Even if the Flickr method doesn’t include the many visitors who don’t upload their photos to the web, it’s better to know that state parks are worth a bare minimum of $1.8 billion to the tourism economy than to assume that they’re worth less.

[h/t Popular Science]

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