What is it?
That's the most common reaction from people. A lot of people have told me they thought it was a computer generated image or some kind of painting rather then a photograph.
What you're seeing is a photograph of life size sculpture of a tree. I came across this sculpture at the National Gallery of Art Sculpture Garden. It's really impressive in-person. Even more so on this day when a storm was quickly approaching. That storm rained and hailed on us just minutes after this photo was taken. It did create an incredible backdrop complimenting the natural shape and highlighting the shiny surface.
The artist is Roxy Paine and the sculpture is called "Graft" from his "Dendroid" collection.
Here is a description with a link from the museums website:
Overview: At 45 feet high by 45 feet wide, Graft (2008–2009) by American sculptor Roxy Paine stands out among the trees in the Sculpture Garden of the National Gallery of Art, one-half mile from the United States Capitol on the National Mall. The Gallery commissioned Paine to make a "Dendroid," as the artist calls his series of treelike sculptures, for the Sculpture Garden. The newly installed work is the first by Paine to enter the Gallery's collection, as well as the first contemporary sculpture to be installed in the Sculpture Garden in the 10 years since it opened.
Made from more than 8,000 components, the stainless steel structure—which weighs approximately 16,000 pounds—was installed the week of October 26–30 by Paine and his crew. The 43-year-old artist has shown his other Dendroids on the roof of the Metropolitan Museum of Art (New York), in the Olympic Sculpture Park (Seattle), and outside the Museum of Modern Art (Fort Worth, Texas), among other locations.
And, here is a link to Roxy's website and his "Dendroid" collection: