There has been considerable debate among ecologists and tree experts about the impact of the storms. From the initial devastation and shock of the morning after, some have argued that the storm damage opened up undermanaged woodlands – let in light, creating structural diversity and valuable deadwood habitats. In areas of plantation and timber crop, the response and reaction of organisations in working together to manage the timber, enabled the impact to be managed, and the crops could be easily replanted.
Many ancient trees and woodlands survived - including the 4000 medieval pollarded oaks of Staverton Park, which were surrounded by the snapped trunks of the conifers at Rendlesham Forest. Even where trees did fall, some remained rooted in the soil, and continued to grow; others have become valuable habitats, with birds nesting in upturned roots, and ponds filling root holes to supporting a wide range of wildlife.
One consequence of the storm was that it engendered a keen interest in the role and importance of deadwood in forest ecosystems. This interest and understanding can be seen in current forest management policy and practice.
20 years on
Ralph Harmer, an ecologist with Forest Research, has been studying the effects of the storm. He writes:
Wind damage is a natural mechanism which has important consequences for the ecology of woodlands. It can:
- Create gaps that allow the regeneration of trees and shrubs;
- Produce open space and bright, sunny, warm conditions that allow flowers, butterflies and other insects to flourish;
- Encourage the development of shrub habitats that will benefit birds and small mammals;
- Provide deadwood following the death of stumps, trunks and branches.
Woodlands and trees are regularly damaged by wind, but its effects are often localised with few trees suffering badly and the damage frequently goes unnoticed.
However the damage caused by the October 1987 storm was widespread, very obvious and initiated a flurry of interest amongst ecologists keen to analyse the ecological impacts of the storm.
Studies during the last 20 years have observed the natural regeneration of the woodland affected. Surveys carried out at storm-damaged broadleaved woodland sites in 1988 and 2002 found that many had regenerated successfully, but the tree species present had changed with many sites dominated by birch. More recently surveys have been carried-out within conifer plantations that were also affected by the storms. The results of these surveys are being evaluated to assess how they can be used to inform the restoration of plantations on ancient woodland sites (PAWS) sites on previous plantation sites (as set out under the Keepers of Time policy). Further details of the studies carried-out can be found on the Forest Research site.
With the regeneration of woodland comes the wider biodiversity of the woodland areas. One of the most interesting consequences in this area has been the increase in the amount of deadwood within southern England's woodlands. While this had been historically low, the impact of the Great Storm of 1987 as well as a subsequent hurricane in 1990, where a great deal of deadwood was left where it fell, has had a dramatic effect on the flora and fauna of local forests.
Many insect species thrive on deadwood and their abundance has an impact on the birds and animals that feed on them. Beetles like the Agrilus pannonicus and Platypus cylindricus , as well as the more common stag beetle (Lucanus cervus) enjoy fresh deadwood, while woodlice (Porcellio scaber) and many other species have found homes under the fallen trees. A host of other species of insects and fungi utilise the wood as it decays and becomes woodland soil. Crevices and rot holes in standing trees filled with detritus provide valuable habitats for centipedes, and rare beetles, such as the lesser stag beetle (Dorcus parallelipipedus). These in turn provide food for birds and bats such as the tree creeper (Certhia familiaris), redstart (Pheonicurus phoenicurus) and the noctule bat (Nyctalus noctula). Noctules are almost completely dependent on holes in dead trees for roost sites and thus benefited significantly from the damage to standing trees wrought by the storm. Deadwood near glades and edges are also important for umbellifers and hawthorns, which provide valuable food sources for adult insects whose larvae develop in the deadwood and both deadwood and glades were created by the Storm.
According to Forestry Commission Ecologist Jonathan Spencer, the interaction of fungi, plants and insects was critical to creating a vibrant woodland habitat.
"To be able to use deadwood, wood-boring insects require wood infected by fungi, as they lack the enzymes to break down and digest uninfected wood. The combination of insects, fungi and rain, produce water-filled rot holes which in turn provide breeding places for numerous flies and beetles. A wide range of invertebrates and birds will find plenty of food sources among that mix too, with upturned roots and logs also acting as important prey 'plucking' sites for birds of prey like the goshawk."
But it was not just the deadwood that supported biodiversity changes; the light and space created where trees were removed benefited woodland ground flora, with a variety of species responding favourably to the disturbance brought by the storm. For example green hound's tongue flushed on many North Downs woodland sites for many years after 1987.
The impact of breeding birds has been monitored in the wake of the Storm. Studies of storm-damaged woods in Suffolk and Sussex, suggested changes in breeding populations, linked to the creation of space often called "treefall gaps" within woodlands. Warblers and Wrens have been drawn to some of these areas, with the increased ground foliage and uprooted trees providing both nest sites and food sources to support them. At Hollesley Heath on the Suffolk coast, the numbers of blackcaps, chiffchaffs and willow warblers increased in years following the storm - the first two most strongly in storm damaged areas. Meanwhile the large-scale clearance caused by the dramatic windblow of pine in Suffolk created areas of new habitat for nightjars and woodlarks. As a result the nightjar population more than doubled in the county between 1987 and 1992, and woodlark populations have similarly benefitted .
Of course not all of the trees blown down by the Storm, died where they fell. Remarkable scenes of regeneration can be found in woodland across the South East where fallen trees have maintained their root systems, and carried on living and growing on the ground.
Alan Betts, Regional Director for the South East of England, often walks in the woodland near his home in Guildford. He said:
"It is amazing to see the trunks lying there, with the branches all heading skywards, and becoming their own trees. In many ways it symbolises how resilient our trees and woodlands are, and how the devastation of the losses felt by the storm have left a unique ecological legacy for possibly hundreds of years to come".