Editing Dutch elm disease (section)

===The "Elm Decline"===
From analysis of fossil pollen in peat samples, it is apparent that elms, an abundant tree in prehistoric times, all but disappeared from northwestern Europe during the [[Holocene climatic optimum|mid-Holocene]] period around 4000 BC, and to a lesser extent around 1000 BC. This roughly synchronous and widespread event has come to be known as the "Elm Decline". When first detected in the mid-20th century, the decline was attributed to the impact of forest-clearance by [[Neolithic]] farmers, and of elm-coppicing for animal fodder, though the numbers of settlers could not have been large. The devastation caused recently by DED has provided an alternative explanation. Examination of subfossil elm wood showing signs of the changes associated with the disease has suggested that a form of DED ''may'' have been responsible. Fossil finds from this period of elm bark beetles support this theory. A consensus today is that the Elm Decline was probably driven by both factors.<ref>{{harvnb|Coleman|2009|p=17}}</ref><ref>{{Cite web |url=http://www.geus.dk/departments/environ-hist-climate/posters/rasmussen97-uk.htm |title=The mid-Holocene Ulmus decline: a new way to evaluate the pathogen hypothesis |access-date=2011-11-04 |archive-url=https://web.archive.org/web/20110928025553/http://www.geus.dk/departments/environ-hist-climate/posters/rasmussen97-uk.htm |archive-date=2011-09-28 |url-status=dead }}</ref>