[[Image:An Oak Tree (conceptual art installation).jpg|thumb|300px|''An Oak Tree'' by [[Michael Craig-Martin]]. 1973]]
'''''An Oak Tree''''' is a conceptual [[work of [[wanker|wankeryart]]<ref>[http://www.modernart.ie/en/page_135922.htm Irish Museum of Modern Art Website] modernart.ie</ref> created by [[Michael Craig-Martin]] in 1973. The piece, described as being an [[oak tree]], is installed in two units – a pristine installation of a glass of water on a glass shelf on metal brackets 253 centimetres above the ground, and a text mounted on the wall. When first exhibited, the text was given as a handout.<ref name=bery>Bery, Bryony. [http://www.tate.org.uk/servlet/ViewWork?cgroupid=-1&workid=27072&searchid=false&roomid=false&tabview=text&texttype=11 "An Oak Tree 1973: Technique and condition text"], [[Tate]], June 2005. Retrieved 8 November 2008.</ref><ref name=manchester>Manchester, Elizabeth. [http://www.tate.org.uk/servlet/ViewWork?cgroupid=-1&workid=27072&searchid=false&roomid=false&tabview=text&texttype=10 "An Oak Tree 1973: Short text], [[Tate]], December 2002. Retrieved 8 November 2008.</ref><ref name =CMtext>[http://web.archive.org/web/20020806040321/http://www.cl.cam.ac.uk/~ig206/oak_tree.html Artist's Text]</ref>
The text takes the form of a Q&A about the artwork, in which Craig-Martin describes changing "a glass of water into a full-grown oak tree without altering the [[accident (philosophy)|accidents]] of the glass of water," and explains that "the actual oak tree is physically present but in the form of the glass of water."
