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!
No comments:
Post a Comment