The arboretum is largely an artificial creation; a garden where exotic trees dominant. However, there are also areas where centuries of traditional management of our native vegetation have left us with a more natural landscape. The Downs grasslands and woodland areas of Silk Wood are the best examples.
Silk Wood
Although partly cleared for arboretum planting during the late 19th Century, Silk Wood retains about 70 ha of what is known as ‘semi-natural’ woodland. This term is used for woodlands that, though made up of naturally occurring trees and shrubs, have been significantly influenced by Man’s management.
We know from historical records that Silk Wood has been intensively managed for many centuries, perhaps back to the 13th Century. The mix of oak trees and hazel shrubs has been maintained by a forestry technique known as coppice-with-standards. The oak ‘standards’ are grown at wide spacing to allow plenty of light for the hazel beneath to thrive. They are harvested at maturity to provide timber for building and other large-scale needs.
The hazel is repeatedly cut or ‘coppiced’ every 8 years or so for sticks or ‘rods’ used in hurdle-making, charcoal burning or a variety of other uses.
After a period of about 60 years neglect we are restoring the cycle of coppice cutting to improve the light conditions for regeneration and return to a sustainable management cycle. This work is carried out by craft coppicers following time-proven methods – albeit with chainsaws!
Many species of wildlife and wildflowers benefit from this management which creates a diverse range of habitats. We are currently carrying out a thorough butterfly survey to find out how many species there are and monitor the effect of our management of the woodland and rides. Fungi have been monitored for many years and at the latest count, the arboretum’s list runs to over 1100 species, some of which are extremely rare.
The Downs
Lying between the car park and Silk Wood, the sloping downs are a fine example of unimproved limestone grassland. This valuable habitat owes its botanical richness to a long history of traditional farming with no fertilisers.
They are best seen in spring and early summer and among the highlights are a number of orchids including green-winged, bee and butterfly orchids.
The open rides that punctuate Silk Wood are also excellent for wildflowers - particularly the northern end of Palmer Ride.
In these areas, we follow management practices aimed at maintaining the open landscape and its biodiversity. These include:
- Grazing the Downs with sheep and cattle to maintain a ‘tight’ sward.
- No application of fertilisers.
- Selective use of electric fencing of some areas to prevent grazing damage to flowers.
- Carefully planned mowing regimes to favour the various flower species in different areas. For example delayed mowing allows late species such as meadow saffron to complete their flowering.
- Removing encroaching shrubs such as hawthorn and sea buckthorn.
The resulting dense shrub layer and open canopy being particularly suitable for woodland flowers and nesting birds like garden warbler and blackcap. In the coming years we hope nightingales will increase in number in response to this improving habitat.
