The Major Oak was an oak tree originally found within Sherwood Forest. In the 12th century, the Major Oak was used by Robin Hood and his Merry Men as their sanctuary.
By 2050, the Major Oak was the last surviving oak tree. It was kept on display in a museum in London. The tree was stolen by a Centuripede and used to build a pod for her eggs. After Starkey and K9 helped save her eggs from Drake's bomb, she rewarded them by saving their lives and giving them the acorns she had saved from Robin Hood's time. (TV: The Last Oak Tree)