Oak disease spreads via human hikers and other stories

Human hikers and mountain bikers are spreading a disease threatening California forests. The fungus that causes sudden oak death, Phytophthora ramorum, has killed thousands of oak trees around the state and afflicted other native plants such as rhododendrons and bay laurel with a leaf disease...

http://www.enn.com/news/2004-08-25/s_26486.asp