"In 2008 the FOR-SITE Foundation, in partnership with the Presidio Trust, commissioned the Spire, a site-specific installation by artist Andy Goldsworthy. The Spire is made from the trunks of thirty-seven cypress trees felled as part of the Presidio’s reforestation effort. From its fifteen-foot diameter, it rises over ninety feet into the air. "
For-Site Foundation website about their commission, with the Presidio Trust, of the site-specific installation. You can explore the Fore-Site Foundation website for info on the first site-specific art installation, "Presidio Habitats."http://www.for-site.org/project/goldsworthy-in-the-presidio-spire/ http://www.presidio.gov/explore/Pages/andy-goldsworthy-spire-wood-line.aspx#.Ugc8wmT5lOg