Sub-Boreal

One of the five postglacial climate and vegetation periods of northern Europe, occurring c 3000-1500 BC or, according to some, 0 AD, based on pollen analysis. The Sub-Boreal, dated by radiocarbon methods, began c 5,100 years ago and ended about 2,200 years ago. It is a division of Holocene chronology (10,000 years ago-present). The Sub-Boreal Climatic Interval followed the Atlantic and preceded the Sub-Atlantic Climatic Interval. It was characterized by a cooler and moister climate than that of the preceding Atlantic period. It is a subdivision of the Flandrian, starting with the Elm Decline. Frequencies of tree pollen fall and herbaceous pollen rises, representing man's invasion of the forest in the Neolithic and Bronze Age. It is correlated with pollen zone VIII, and the climate was warm and dry. The Sub-Boreal forests were dominated by oak and ash and show the first evidence of extensive burning and clearance by humans. Domesticated animals and natural fauna were abundant.

A climatic sub-division of the Flandrian, originally supposed to be warm and dry, in contrast to a wet and warm preceding Atlantic period. Godwin’s Pollen Zone Vllb corresponds to the Sub-Boreal period in Britain. The zone starts with the elm decline. Its end is rather ill-defined over much of Britain (see Sub-Atlantic). Frequencies of tree pollen fall through Zone Vllb, and herbaceous pollen rises correspondingly. This represents man’s invasion of the forest in the Neolithic and Bronze Age. This consisted in many areas of temporary land-NAM-type clearances, but permanent clearance also occurred in some parts of the British Isles.