Recent pine woodland dynamics in east Glen Affric, northern Scotland, from highly resolved palaeoecological analyses

Abstract

Glen Affric, a National Nature Reserve of international conservation importance for plant and animal communities associated with Scots pine ( Pinus sylvestris ) woodland is managed for nature conservation and woodland restoration at a landscape scale. Management plans have drawn on information on current stand structure and variation but have not used in any detailed way the analyses of past tree population changes from sources, such as pollen analyses. This paper reports the results of pollen analyses from three small peat hollows at the head of Loch Beinn a' Mheadhoin. The analyses demonstrate, fi rst, that woods in the east of the reserve several centuries ago were different in species composition and were more varied than they are today and, second, that the currently patchy Pinus wood in the west of the reserve, at the head of Loch Beinn a' Mheadhoin, is the result of recent spread westward onto former heathland. This temporal and spatial variability in the recent past has implications for the future management of the woods because future woods may not develop with the characteristics of the current stands, and may not be stable over time.

Scottish upland forests: History lessons for the future

“…Observed ring counts indicate pine of over 300 years. This is consistent with the pollen records, which show an open and fluctuating woodland structure in the east of Glen Affric at this time (Shaw and Tipping, 2006).…”

Ecology and management history drive spatial genetic structure in Scots pine

“…Stand composition is dominated by Scots pine and the vegetation layer is predominantly C. vulgaris with small patches of V. vitis-idaea and V. myrtillus. Evidence from pollen records from west Glen Affric, where our stand is located, show a sustained low tree cover around these sites for several thousand years as a result of prolonged human impact, with the recent expansion of the forest when the present tree cohort developed around 1880 (Shaw, 2006). Historical documents report felling of trees during the 18 th and 19 th Centuries (Smout et al, 2005) with the decline evident in pollen records.…”

“…Drastic reduction of population sizes can induce higher rates of selfing and mating between relatives (Robledo-Arnuncio et al, 2004a). The small size of the population at the time of establishment of the current adult cohorts, as indicated by historical data (Shaw, 2006;Summers et al, 2008), might explain this pattern.…”

“…The larger extent of SGS observed in Glen Affric may arise from local differences in historical management, with a prolonged limited tree cover due to human activities (Shaw, 2006), which is also reflected in the lower density of the site. The very short spatial scale of genetic structure in the mature unmanaged stand was remarkably similar to that in undisturbed continuous populations of P. pinaster which displayed either weak or no relatedness, with maximum values of SGSMAX of 10 metres (De-Lucas et al 2009).…”

Open Structured Woodland and the Ecological Interpretation of Scotland's Ancient Woodland Inventory

“…Second, the use of maps to identify individual sites with various densities of scattered trees -in this case, AWI Class 3 polygons -could be expanded conceptually to recognise the importance of the historical landscape matrix (Lindborg & Eriksson 2004;Ellis & Coppins 2007), and using habitat connectivity which quantifies woodland densities at contrasting spatial scales in the landscape. This would further benefit from the alignment of multiple types of evidence, with palaeoecological analysis now providing the opportunity to partition trends in woodland structure between the wider landscape and local woodland stands, as demonstrated for eastern Glen Affric (Froyd & Bennett 2006;Shaw & Tipping 2006), and at a sufficiently high resolution to provide a complement to the analysis of historical maps.…”