Climate, Vegetation and the Complex History of Pinus sylvestris during the Holocene, in Wester Ross, Northwest Scotland.

Abstract

The close proximity of the North Atlantic to Wester Ross makes the vegetational, climatological and anthropogenic history of the region particularly interesting. This study aims to reconstruct these three aspects of the Holocene from peat deposits at Meall Bad á Chrotha. Such studies are vital if we are to improve our understanding of current climate change and prepare for the future implications it may cause.
The warming climate of the Lateglacial and early Holocene saw the terrestrialisation of the lake which occupied the site and subsequent establishment of mixed Betula/Corylus woodland. The continued rise in summer temperatures led to the Mid-Holocene Thermal Maximum and the associated replacement of mixed woodland by Pinus sylvestris. It is likely that dense pine forest occupied the area by 7000 cal BP, encouraged by the drier conditions and possibly the occasional, small-scale wild or domestic fire. The lack of evidence for Mesolithic-Neolithic activity within the record is fairly unsurprising due to the high altitude and exposed nature of the site; however, there is evidence for early activity elsewhere on the South Erradale Peninsula.
The ‘Mid-Holocene Pine Decline’ is a distinctive part of the vegetational history of Meall Bad á Chrotha most probably occurring in response to a substantial reduction in summer temperatures. This climatic deterioration known as the ‘Holocene Thermal Decline’ and subsequent wet shift can be linked to an ice rafted debris event which occurred in the North Atlantic around 4200 years ago (Bond et al, 1997). Minor rises in Plantago lanceolata and charcoal from the mid-late Holocene most likely represent the intensification of land use in the valley below as communities exploited the newly open landscape, and were perhaps responsible for the continued fall in arboreal pollen. The temperature continues to fall below early Holocene values with a rise in water-tolerant communities and peat-forming conditions towards present day.