Prehistoric Pinus woodland dynamics in an upland landscape in northern Scotland: the roles of climate change and human impact

Abstract

Pollen, microscopic charcoal, palaeohydrological and dendrochronological analyses are applied to a radiocarbon and tephrochronologically dated mid Holocene (ca. 8500–3000 cal B.P.) peat sequence with abundant fossil Pinus (pine) wood. The Pinus populations on peat fluctuated considerably over the period in question. Colonisation by Pinus from ca. 7900–7600 cal B.P. appears to have had no specific environmental trigger; it was probably determined by the rate of migration from particular populations. The second phase, at ca. 5000–4400 cal B.P., was facilitated by anthropogenic interference that reduced competition from other trees. The pollen record shows two Pinus declines. The first at ca. 6200–5500 cal B.P. was caused by a series of rapid and frequent climatic shifts. The second, the so-called pine decline, was very gradual (ca. 4200–3300 cal B.P.) at Loch Farlary and may not have been related to climate change as is often supposed. Low intensity but sustained grazing pressures were more important. Throughout the mid Holocene, the frequency and intensity of burning in these open Pinus–Calluna woods were probably highly sensitive to hydrological (climatic) change. Axe marks on several trees are related to the mid to late Bronze Age, i.e., long after the trees had died

Quantifying seasonal precipitation using high-resolution carbon isotope analyses in evergreen wood

“…Non-permineralized, fossil wood is abundantly available from the Quaternary, including Holocene (Clague et al, 1992;Ferrio et al, 2006;Noshiro et al, 2007;Tipping et al, 2008;Kaiser et al, 2009) and Pleistocene (Burgh, 1974;Leavitt and Long, 1991;Mijarra et al, 2007) sediments, and has also been documented extensively throughout the Tertiary [Pliocene (Martinetto et al, 2007;Vassio et al, 2008;Baldanza et al, 2009), Miocene Erdei et al, 2009), Eocene (Jahren, 2007), Paleocene (Blanchette et al, 1991)] and Cretaceous (Grö cke et al, 1999;Yans et al, 2010). This method is particularly applicable to fossil wood pieces because only relative changes in the d 13 C value are required, thus we may discount any consistent digenetic alteration or juvenility effects (Gagen et al, 2007Esper et al, 2010).…”

Forest vegetation responses to climate and environmental change: A case study from Changbai Mountain, NE China

“…During prehistoric times, plants could partly adjust to natural variations in temperature and precipitation by latitudinal and altitudinal shifts in their distribution ranges (Grayson, 2005;Tipping et al, 2008;Zenner and Berger, 2008). It was only with the onset of anthropogenic activities and the resulting strong increase in the fragmentation of natural habitats that the ability of plant species to adjust to changes in climatic conditions via shifts in their distribution ranges became severely limited (Liira et al, 2007;Malhi et al, 2008).…”

Response to late Bronze Age climate change of farming communities in north east Scotland

“…These vegetation and land-use changes took place in a dry climate which was established at around 5720 cal. BP (Tipping et al, 2007b). After c. 2900 cal.…”

“…Blanket peat next to this lake contains pine wood remains with later prehistoric axe marks (Tipping et al, 2007a). A 6 m deep fen at the edge of Loch Farlary, next to the blanket peat, contains a full Holocene sediment sequence dated by seven AMS 14 C assays and two tephrochronological horizons (Tipping et al, 2007b). Analyses of this fen peat included pollen analyses, entirely comparable to those at Reidchalmai, and peat humification analyses (see Tipping et al, 2007b).…”

“…4 presents the pattern of changing peat surface wetness obtained from this measure between 4500 and 2000 cal. BP, in this context probably driven by variations in effective precipitation (Tipping et al, 2007b). Selected pollen data are presented in Fig.…”