This is the Pumice Desert in Crater Lake National Park (OR) and it is located about six miles north of the actual crater. It was formed about 7,700 years ago from the pumice ejected by the ancient volcano, Mt. Mazama. You can see the great expanse of the desert as well as the myriad tiny holes in the piece of pumice.
The sign at the lookout area said that it will take thousands of years for a forest to get established here due to the poor quality of the soil. It is quite a contrast to go from here to the beauty of the lake up in the caldera.