Nature, Culture, and Conservation in the Anthropocene - Biodiversity Conservation and Environmental Change - page 155

woodland composition, biodiversity and resilience to changing environmental conditions
(Harmer and Britain 1999, Tipping et al. 1999, Brown 2010).
Pollen records show the dynamic nature of forest composition over time, in response to
environmental change and human management. From the early Holocene, birch, hazel, elm,
oak, and pine colonized northern England and Scotland from warmer refugia in southern
Britain and continental Europe. Human management of forests over the following millennia
increased habitat for light and disturbance adapted taxa and enhanced the abundance of
favoured species like oak (Tipping et al. 1999, Brown 2010, Davies 2007, 2011). Pollen records
from over 200 sites in Scotland show that about 6,000 years ago, birch, pine, oak, and hazel
dominated forests were common, while unwooded areas were probably relatively scarce
(Tipping et al. 1999) (Figure 7.4b). At this time, global climate was relatively warm (see Chap-
ter 5) and therefore this period provides an appropriate climatic benchmark. Following
human arrival, light- and disturbance-adapted taxa like ash ( Fraxinus ) and alder ( Alnus )
increased, as did the abundance of grass pollen, indicating a more open canopy and
enhanced grazing for animals. Elm ( Ulmus ) declined as a result of harvesting for its prized
timber, and this allowed lime ( Tilia ) to spread into areas where it would previously have been
excluded through competition. Furthermore, agropastoral communities enriched forest
diversity by opening up the canopy and introducing plants used for medicine, construction,
and food. Thus the post-anthropogenic, semi-natural woodland assemblage was both more
biodiverse and more rich in cultural history than the 'past-natural' undisturbed woodlands
that occurred prior to 6,000 years ago (Tipping et al. 1999).
In the Wentwood, Wales, Brown (2010) used fossil pollen to explore changes in woodland
composition and found evidence that oak-hazel ( Quercus - Corylus ) woodland was exten-
sively cleared during Roman times, but a different tree cover, dominated by ash and birch
( Fraxinus and Betula ) regenerated in the third to the fifth centuries ce, following which a
mosaic of oak-hazel-ash woodland and open pastures were developed by agro-pastoralist
communities. From the twelfth to the nineteenth centuries, beech ( Fagus ) was also planted,
initially for coppicing, which produces thin poles convenient for building and fencing, and
later for timber that is highly valued in furniture making. Traditional agropastoralism was
disrupted during the Enclosures Acts and in the late nineteenth century, native broadleaved
species were replaced by fast-growing conifer plantations (Brown 2010). Though pre-conifer
woodland composition might seem like a logical benchmark, in fact climate was cooler then
due to the Little Ice Age, and it is predicted that beech will not fare well in the face of warming
climates and more intense storms, because of its shallow rooting system (Brown 2010). Ash is
declining due to attacks by fungus, while lime and elm are poor seeders, and would need to
be actively planted to restore abundances seen in medieval times. In contrast, oak, hazel, ash,
and birch were present before the planting of conifers, and regenerate well in secondary
woodland. They could all contribute to woodland restoration plans though their abundances
have changed over time making restoration benchmarks complex (Peterken 1996).
'Future natural' or 'neo-native' woodlands could include a wide range of species, like holly,
rowan, hornbeam, aspen, field maple, and gorse oak, alongside the historically dominant taxa
like birch, ash, hazel, oak, and hawthorn, thereby increasing biodiversity and resilience