Contribution to he knowledge of the holocene vegetation in the NW of the Iberian Peninsula(Galicia, Spain)

[Abstract] A paleobocanic scudy ofcwo Galician sierras, Coure! siecra and Queixa-Invernadoiro sierra is presenced here. A palynological scudy ofche Laguna Lucenza was carried ouC in che Coure! sierra. Eighc radiocarbon daces were obcained, covering che lasc 9,000 years. In che Queixa-Invernadoiro sierra a palynological scudy was carried ouc in four sequences, which are supporred by four radiocarbon daces, covering approximace!y che lasc 8,000 years. The onsec ofche Holocene is characcerized by che scrong expansion ofoak woodland following a shorr phase ofbirch foresc along wich che gradual decline of pine. Oak woodland began ro expand during che Boreal reaching a maximum ac 8,3SO±80 BP. Towards 8,800 BPCorylus began roexpand, followed by Alnus (7 ,SOO BP) and Ulmus. In che Queixa sierra chere is a local colonizacion of birch, hiding che regional predominance of oak. During che Subboreal chere is a gradual decline of arboreal pollen and Castanea appears (4,07S±7S BP). There is a clear anchropogenic deforescacion during che lasc 4,000 years. In che firsc inscance chere is a deforescacion leading ro che exiscence of open zones. The presence oflarge quancicies of microscopic carbon parricles proves che exiscence of fire. Lacer che arrival of agriculcure accencuaces che disappearance of che forescs. Neverche!ess, alcicude will condicion sensibly che appearance of caxa indicacors of agriculcural processes