By Dr Tony Whitbread
The night of 15th October 1987 saw storm force winds around 100 mph hitting the south eastern corner of Britain – from Hampshire to Suffolk, some 14 counties in all. This followed a time of heavy rainfall, soils were water-logged and, being a mild autumn, the trees were still in leaf. So the full force of the storm hit at a time when trees were actually quite vulnerable.
In practice, however, the wind came with such force that enormous amounts of disturbance were inevitable. Some 15 million trees (probably an under-estimate) had been windthrown (uprooted) or wind-snapped (broken at the stem). In addition and uncountable number of trees had experienced major loss of branches from the crown.
The effects were dramatic. Huge areas had blown flat and, even more frequently, holes of various sizes had been blown into woods. Swathes of damage and canopy gaps had appeared everywhere.
Strangely, trees seem much bigger when they are laying down than when standing up! The amount of wood just lying around was enormous
In terms of living memory, this sort of event is so rare that it was considered a freak of nature. No one could remember anything like this. But trees live for a long time – forests even longer. There have been similar events in the past - the great storm of 1703 being even more devastating. Storms like this may have a return time of around 200 to 300 years. On the scale of the life span of individual trees, and in terms of the age of whole forests, this was not an unusual event.
So – what were the real effects of the storm on our woods and forests?
A dispassionate examination of what actually happened to the ecology of forests gives a very different picture to the tales of destruction so beloved of the media reports. The areas blown flat and the canopy gaps created, generated great diversity in forests that had often become dense and over shadowed. Light was able to get to the forest floor, often for the first time in decades. In the years that followed we saw a burst of regrowth of the ground flora. Species flourished where they had previously been overshadowed, in some places species appeared (heather for instance) that had not been seen in a wood for many decades. Insect life flourished and birds were drawn into the newly created patches.
As the years went by we saw shrubs regenerating in gaps – species that would not have stood a chance under dense woodland. As light got into the forest shrubs were able to flower, attracting nectar-feeding insects – and insect eating birds. Trees sprouted from broken limbs or crushed root plates and spread to fill in the gaps that had formed. In bigger gaps there was a flush of regenerating tree seedlings – a diversity of species often far greater than was represented in the earlier woodland canopy.
Changes to structure also had unforeseen effects. Damaged trees supported more fungi and wood boring insects, hole nesting birds had more of a chance to nest and piles of decomposing brushwood provided nesting, roosting and foraging sites for birds and small mammals. Windblown trees left upturned root plates, regeneration sites for plants and shrubs, and water filled hollows used by wetland plants and amphibians. We had a case of kingfisher nesting in an upturned root plate here at Woods Mill.
One worry after the 1987 storm was the human need to do something – an impetus to clear up the mess and get things back to the way they should be. Whilst management might have been entirely justified in special places (tree collections and arboreta for instance) tidying up afterwards caused far more damage to our woods than did the storm.
There may have been great mortality of wildlife on the night of the storm. But the living space created by the storms beneficial disturbance created enormous opportunity for all manner of wildlife which was able to thrive as a result.
When it comes to wildlife, nature and forests – storms are great!