Pollen can provide information on cultivated and wild plants as well as woodland. Information is generally gathered now in most projects, although as shown in section 3.2.1, is rarely pulled together to form a local or regional picture (but see Bunting and Farrell 2018). Although pollen is the most common source used to document and date vegetation changes, Birks argued the need to validate with other independent evidence such as macrofossils, which unlike wind-dispersed pollen are more likely to be local indicators. Dating obtained on pollen and macrofossils, for example on pine from Abernethy, Strathspey showed a difference of around 150 years (Birks 2003). However, it is important to note that pine needles degrade in peat and that pine pollen travels far from the parent tree. Studies have shown that pollen percentages of just 1.5 to 3% Total Land Pollen may indicate the local present of pine (see discussion in Timpany et al 2020, 16).
Some evidence may relate to a local situation while others to a more regional picture. The pollen collected from Loch Sionascaig in Wester Ross and the largest island in the loch, Eilean Mor, was intensively studied by pollen analysis, diatom analysis and sediment geochemistry. The Loch Sionascaig material is likely to have derived from a large source area, and has been interpreted as a regional record. Pollen investigation of a bog on Eilean Mor provided a different pollen diagram from the loch, and provides a good picture of the development of peat (Birks 1993). This reflects the need for a multiple core approach.
The general picture of woodland colonisation, including the importance and widespread nature of hazel is noted in National ScARF (Palaeolithic & Mesolithic section 3.2.2), leading to a general predominance of birch, hazel and alder, with survival in places of oak and pine. However other studies allow further nuances to be discerned. Evidence of past woodland can be determined from pollen, charcoal, and macrofossil data including preserved seeds. Charcoal in particular can provide a wealth of information, not only on species which are often hidden in pollen analysis and dating, but also cutting techniques and insights into woodland management, including burning and possible coppicing and pollarding.
Richard Tipping’s overview (1994) includes a wealth of information for the Highlands based on over 40 sites, though much of the work was before secure radiocarbon dating. However, he noted that very few pollen diagrams from the northern mainland were keyed to archaeological concerns. He cited the cases of An Druim and Loch Assynt in northwest Scotland and Loch of Winless in eastern Caithness, and questioned whether the focus on lake sites has given a misleading impression of human activity, or the lack thereof, in the record (Tipping 1994, 24). Since 1994 there have been a few other studies (see Map 3.1), but there are still undoubtedly gaps in our record
Map 3.1 Pollen studies with more than one radiocarbon date
Based on Tipping 1994, with black numbers relating to sites. Green stars: selected studies since 1994. © Scott Timpany
Surviving woodland today may be less diverse than in prehistory, when pollen analysis shows variety even within some regions. Small areas of woodland in largely treeless landscapes can be missing in some pollen records but detected in others, suggesting that closer investigation is needed in many of these areas (Bunting and Farrell 2018). More waterlogged plant remains evidence is needed to go alongside pollen to investigate the biodiversity.
More attention should be directed to whether one tree species dominated primary woodlands or whether mixing was the norm, and if this changed over time; see for example, work at Glen Affric (Tipping 2003; Davies and Tipping 2004; Davies et al 2004; Tipping et al 2006), Migdale, Sutherland (Davies et al 2017) and the Garbh Allt catchment area near Golspie (Tipping and McCullagh 2003; Tipping et al 2008a; 2008b). The Highlands have good potential to explore issues of the species diversity using pollen and macrofossil evidence.
Tipping (1994) has shown that there are general differences in areas in the Highlands. Central Sutherland and Caithness were colonised by pine, with different periods of decline and sometimes regeneration in different areas (Davies et al 2017). South of the Great Glen there was also pine, but the records show different patterns of clearance and recolonization (Wilson et al 2011). To the west pine was not dominant, replaced by oak in places (Green and Edwards 2009). On Skye, birch and hazel were the main species, but more studies are needed to show if this is too generalised (Tipping 1994). There are other areas which need more work and studies involving radiocarbon dating, including Easter Ross, along the Great Glen and Nairnshire. Even within these generalisations, however, studies have shown survival of woodland in microclimates (Davies et al 2017). Recent work investigating native woodland cover in certain areas of the Highlands is being used to inform replanting schemes (eg Davies 2011; Sybenga 2020; work in progress by Rob Wilson at St Andrews University), a good example showing how commercial concerns can be allied to archaeological research.
Much of the work in the Highlands relates to woodland growing on peat, and further work is needed to see if there are differences for those growing on mineral soils, as was tackled in work at Glen Affric (Davies et al 2004; Tipping et al 2006) and the Garbh Allt catchment area near Golspie, Sutherland (Tipping and McCullagh 2003; Tipping et al 2008a; 2008b).
In the Highlands, there has also been attention directed towards the spread and demise of Scots pine (eg Birks 1972; 1975; 1993; Blackford et al 1992; Charman 1994; Tipping et al 2007b; 2008a: 2008b; Timpany 2008; Wilson et al 2011; Davies et al 2017). Early evidence for colonisation in the region survives around Loch Maree in Wester Ross around 6500 BC. The source of the seeds is not clear, but was perhaps Ireland. Without oak or elm to compete against, pine dominated throughout much of the Highlands. However, the picture is complicated, as genetic difference between pines in different areas have been identified (Birks 1972; Tipping 2003a, 20-22). Pine then has a complex history in the northern Highlands.
While a number of studies suggest an abrupt decline around 4000 cal BP/ 2050 cal BC (Wilson et al 2011), this now is seen clearly as too simplistic (Tipping et al 2008a, 252; Davies et al 2017). Detailed work at Loch Farlary, showed two declines, the first c. 6200-5500 cal BP/4250–3550 cal BC caused by rapid and frequent climatic shifts, the second c. 4200-3300 cal BP/ 2250-1350 cal BC far more gradual. This suggests that the second decline at Loch Farlary was not linked to climate though the reasons are not entirely clear (Tipping et al 2008a). Elsewhere such as parts of Glen Affric, there appears to have been fairly continuous growth of pine (Tipping et al 2006). Altogether this shows a complex and locally sensitive situation in the Highlands, with dendrochronology of pine stumps holding some promise for future refinement (Wilson et al 2011). There is potential to conduct multi-proxy approaches including pollen, insects and dendrochronology to really explore pine decline across the region.
The interpretation of human action in woodland management is a difficult one (Tipping 1994; Bishop et al 2015, 67-68). The need for further work to try and determine whether climate or human activity is the main factor in woodland changes has been highlighted by National ScARF. How long did ‘primary’ woodland last in areas of the Highlands? What would these ‘primary’ woodlands comprise of? (ScARF Bronze Age section 3.1).
A pollen modelling study in Coigach, Wester Ross, was pioneering to try and assess what pollen in the archaeological record can tells us, by also focussing on modern pollen rates and dispersal, issues involving climate, hydrology, topography and landscape. The effect of woodland management practices in the pollen records are also beginning to be investigated though modelling, an area of investigation important for the Highlands (Bunting and Farrell 2018).
|Loch of Winlass, Caithness||Peglar 1979|
|Aukhorn, Keiss, Caithness||Robinson 1987|
|Braehour, Rowens, Caithness; Dalchork, Sutherland||Sybenga 2020, with refs to other studies in the area|
|Suisgill, Helmsdale, Sutherland||Andrews et al 1985; Tipping 1994, 25|
|Garbh Allt catchment area near Golspie, Sutherland||Tipping et al 2008a; 2008b|
|Kilbraur, near Golspie||Timpany 2010|
|Strath of Kildonan, Sutherland||Charman et al 1995 (with special attention to volcanic tephra), Gillie 2003|
|Lairg, Sutherland||McCullagh and Tipping 1998; Smith 1998|
|Migdale, Sutherland||Davies et al 2017|
|NW Sutherland (various sites)||Pennington et al 1972; Davies 2011|
|Coire Bog, Wester Fearn, Ross & Cromarty||Birks 1975|
|Culduthel, Inverness||Timpany et al 2021 forthcoming|
|Glen Affric||Tipping 2003b; Davies and Tipping 2004; Davies et al 2004; Tipping et al 2006; Davies 2007; Tipping 2008|
|Strathpey||Loch Einich and Allt na Feithe Sheilich (Birks 1975), Loch Pityoulish (O’Sullivan 1976), Tore Hill Moss (Blundell and Barber 2005)|
|Loch Maree, W. Ross||Birks 1973|
|Loch Sionascaig, W. Ross||Pennington et al 1974, 191-294; Birks 1993|
|Glen Torridon, Glen Carron, Loch Maree, Beinn Dearg, W. Ross||Anderson et al 1998; Anderson 1998|
|Badentarbat, Coigach, W. Ross||Bunting and Tipping 2004.|
|Skye||Birks 1973; Birks 1983; Walker and Lowe 1990; Selby 2004 (with refs to other work on Skye)|
|Dail na Caraidh, Lochaber||Barrett and Gourlay 1999. Dated core near to BA hoard|
|Arisaig area, Lochaber||Carter et al 2005. Useful for this area of the country, with attention to local and regional changes|