HOLOCENE FIRE IN THE SCOTTISH HIGHLANDS: EVIDENCE FROM MACROSCOPIC CHARCOAL RECORDS

Abstract

It has been hypothesized that the mid-Holocene decline of pine (Pinus sylvestris L.) woodland in the Scottish Highlands may have been the result of a change in the fire regime of the region. Little is known about the Holocene fire history of these forests, although a number of factors suggest that fire may have played a significant role. This study examines whether fire was a prevalent factor in Scotland over the course of the Holocene and its relationship with Highland vegetation communities. Both macroscopic and microscopic charcoal are analysed in conjunction with a full palynological investigation from four Holocene lake sedimentary sequences in locations throughout the Scottish Highlands. Comparison of macroscopic charcoal abundance profiles with those from areas of known wildfire activity and the consistent pattern of burning revealed across the four disparate Highland sites indicate that broad-scale burning of vegetation did occur. Charcoal abundance was related to vegetation composition at all four of the sites examined. The abundance of pine, however, was found to be unrelated to fire history. Instead, fire appears to be predominantly linked to the development of heath and blanket mire communities. Analysis of three different macroscopic charcoal size fractions (? 500 gm, 250-500 gm and 125-250 gm) revealed strong correlations between measures. Microscopic charcoal abundance, however, was more variable and was determined to be a less accurate measure of local catchment-scale burning within the region.