Elm Decline

A phase in the history of northern European vegetation recognized through pollen analysis and dated by radiocarbon as c 4000 BC. It marked a sudden and marked decline in elm pollen in contrast to other tree pollens. In some areas it was accompanied by a drop in frost-sensitive species such as ivy and mistletoe, while in many others it coincided with the appearance of plants associated with human settlements (plantain and nettles). It is now attributed to disease from beetles causing Dutch elm disease though other explanations for the decline include climatic change and human interference.

A permanent fall in elm pollen, seen in pollen diagrams from Britain and Northern Europe. In diagrams plotted from proportional pollen counts, other trees are largely unaffected. Radiocarbon dates for the elm decline in Britain mostly fall between 3300 and 3100 be, some time after the first appearance of Neolithic culture. Explanations for the decline include climatic change, a rapidly spreading selective disease, and human interference. But in a number of diagrams plotted from absolute pollen counts it has been shown that although elm declines most markedly other trees are affected as well. This makes disease a far less likely cause. In addition, small transient forest clearances are increasingly being shown in pollen diagrams, just before and during the elm decline. It is therefore quite reasonable to suggest that elm may have been particularly affected by man’s activities in the forest. Elm is among the most palatable of tree foliage, and it may be that Neolithic cattle browsing in the forest, and the gathering of foliage for their winter fodder, caused the selective decline of the elm.