How would you determine if a tree qualifies as a "national champion"? The National Register of Big Trees has the answers, and the 70th anniversary edition of that list just been released in a new online format. Sites in the National Park System are well-represented, including the home of "the earth's largest living thing."

It's been a tough week for the oil and gas industry, one which has held plenty of anxious moments for several NPS areas located in the vicinity of recent accidents. The latest involved an explosion at a refinery near San Antonio Missions National Historic Park; two of the historic structures were closed temporarily and precautionary measures were taken for possible contamination of important waterways.

Here's a photo contest for all you amateur Civil War buffs. Sponsored by the Civil War Preservation Trust, the Center for Civil War Photography, and History, the deadline to get your images in for consideration is August 31.

The showy tamarisk tree, aka "Saltcedar," long has been reviled as a thirsty scourge of Western national park riparian areas. But new research shows it's not any thirstier than some native species. However, tamarisk isn't valued as highly as cottonwoods and willows by some bird species, the studies say.