Cumbria contains large areas of broadleaved woodland in all parts of the county. Before man started to modify the landscape about 5000 years ago, most land up to a height of about 2000 ft would have been covered in woodland. We know from pollen analysis of lake sediments, that by Neolithic times man was clearing woodland using locally manufactured stone axes to make grazing available for livestock. This would not have been clear felling, some trees would have been left to form a ‘Wood Pasture’ habitat, but as a result of subsequent grazing pressure, regeneration did not take place and as the old wood pasture trees died there was nothing to replace them.
The natural climax vegetation in Cumbria is the Sessile Oakwood and the nearest habitat to this are the small Keskadale woodlands of pure Sessile Oak found high in the Newlands valley near Keswick. There are also very fine examples of Sessile Oak woodland in the Borrowdale valley.
Most woodland in Cumbria today is mixed Oak, Birch, Ash, and Elm with Alder in the wetter areas, Hazel and Holly as an understory and a rich ground flora. Much of this woodland was formerly exploited for woodland industries (in particular for Charcoal production) and has been managed for centuries as enclosed coppice but now mostly left to grow into a semi natural condition. The evidence of former coppice management is still apparent in many of these woodlands in the form of multi stemmed trees and the flat circular floors of the charcoal kilns.
The fact that these woodlands were extremely valuable as recently as 150yrs ago has ensured their survival today, a survival that is entirely due to the rigorous exclusion of browsing animals, especially sheep. This allowed regrowth of coppice stools after cutting and growth of seedlings.
This is the woodland that would historically have been a stronghold of the Pearl Bordered Fritillary and High Brown Fritillary that thrived on violets which proliferated in the sunny and warm newly cut coppice coupes.
This butterfly along with the Silver Washed and High Brown Fritillaries can still be found on a few sites in the mixed woodlands of the limestone soils in south Cumbria where rotational coppicing still takes place. However as this process is not economically viable, it is only normally carried out where woodland is managed for conservation purposes.
The largest single threat to long term health of our broadleaved woodlands is browsing by the large population of deer and huge numbers of sheep. This prevents natural regeneration taking place unless woodland is securely fenced to exclude sheep and deer numbers are heavily controlled by culling. Cessation of coppicing is equally damaging and it makes the woodland habitat unsuitable for most butterflies because as the canopy closes, sunlight, larval foodplants and nectar sources are excluded. One of the few butterflies that can tolerate such shaded conditions is the Speckled Wood that is especially common in the South Cumbria woodlands.
Good examples of woodland being managed for butterflies by rotational coppicing is How Ridding Wood north of Witherslack and Gait Barrows NNR near Arnside.