Contribución al conocimiento de la vegetación holocena en el NO de la Península Ibérica (Galicia, España)

Resumen

A paleobotanic study of two Galician sierras, Courel sierra and Queixa-Invernadoiro sierra is presented here. A palynological study of the Laguna Lucenza was carried out in che Courel sierra. Eight radiocarbon dates were obtained, covering the last 9,000 years. In the Queixa-Invernadoiro sierra a palynological study was carried out in four sequences, which are supported by four radiocarbon dates, covering approximately the last 8,000 years. The onset of the Holocene is characterized by the strong expansion of oak woodland following a short phase of birch forest along with the gradual decline of pine. Oak woodland began to expand during the Boreal reaching a maximum at 8,350±80 BP. Towards 8,800 BP Corylus began to expand, followed by Alnus (7,500 BP) and Ulmus. In the Queixa sierra there is a local colonization of birch, hiding the regional predominance of oak. During the Subboreal there is a gradual decline of arboreal pollen and Castanea appears (4,075±75 BP). There is a clear anthropogenic deforestation during the last 4,000 years. In the first instance there is a deforestation leading to the existence of open zones. The presence of large quantities of microscopic carbon particles proves the existence of fire. Later the arrival of agriculture accentuates the disappearance of the forests. Nevertheless, altitude will condition sensibly the appearance of taxa indicators of agricultural processes.