Wistman’s
Wood, Dartmoor National Park, where many oaks are more than 500 years old.
The gift we should give to the living world?
Time, and lots of it
George
Monbiot
Planting 10 saplings does not replace a twisted old
oak. ‘Slow ecology’ is the only way to preserve and restore ancient habitats
Sun 8 Aug
2021 14.00 BST
We have a
slow food movement and a slow travel movement. But we’re missing something, and
its absence contributes to our escalating crisis. We need a slow ecology
movement, and we need it fast.
The
majority of the world’s species cannot withstand any significant disruption of
their habitat by humans. Healthy ecosystems depend to a great extent on old and
gnarly places, that might take centuries to develop, and are rich in what
ecologists call “spatial heterogeneity”: complex natural architecture. They
need, for example, giant trees, whose knotty entrails are split and rotten;
great reefs of coral or oysters or honeycomb worms; braiding, meandering rivers
full of snags and beaver dams; undisturbed soils reamed by roots and holes. The
loss of these ancient habitats is one of the factors driving the global shift
from large, slow-growing creatures to the small, short-lived species able to
survive our onslaughts. Slow ecology would protect and create our future
ancient habitats.
At the
moment, we’re going in the opposite direction. Self-serving nonsense cooked up
by governments and their advisers, such as “natural capital accounting” and
“biodiversity net gain” treat one habitat or feature as exchangeable for
another. Don’t lament the twisted old oak we’re felling: we’ll plant 10
saplings in plastic rabbit guards in its place. Then we’ll call it a “net
gain”.
But there’s
no substitute for an ancient tree, or an ancient anything else. Big old trees
are the “keystone structures” of forests, on which many other species depend.
The very trees that foresters have tended to weed out – forked, twisted,
lightning-struck, rotten, dead – are those that harbour the most life. For
example, a single species of bracket fungus, which grows on rotten branches
(dryad’s saddle), harbours 246 species of beetle.
Bats
shelter in splits in the trunk. Forks hold tiny pools of water or pockets of
soil. Jagged wounds where limbs have sheared, burrs and excrescences, scrapes
from which resin bubbles, ivy, vines, lichens and mosses, tangles of twigs and
derelict nests, peeling bark and fire scars are all crucial wildlife habitats.
But the most important features of ancient trees – and many other habitats –
are holes.
Between 10%
and 40% of the world’s forest birds and mammals need holes in trees in which to
nest or roost. Many other animals – amphibians, reptiles, invertebrates –
depend on them. But these species suffer from a void of voids, an absence of
absences.
Holes take
many forms: hollow trunks or branches, galleries mined by insects, cavities dug
by woodpeckers. Woodpeckers are keystone species, whose tunnelling makes homes
for other nesting birds and mammals. They appear to spread fungal spores on
their beaks in the same way that bees spread pollen, and this helps create the
soft wood into which they can drill. The trees they need are big, old and
rotten.
But almost
everywhere, trees like this are disappearing. Research in Poland, France,
Scandinavia, the Balkans and the Carpathians shows that forests unmanaged by
people have far greater numbers of crucial features than even those whose trees
are harvested in the most sensitive ways. In France, for example, the number of
broken forks increased by nearly 300% in the 50 years since forests were last
harvested, and holes made by woodpeckers by 500%.
A study in
Australia showed that, following a major wildfire, the great majority of trees
with holes were wiped out. It will take up to 120 years without further
disturbance for their full ecological complexity to recover.
Our
tidy-minded forestry and our habit of treating trees as interchangeable are
devastating to wildlife. “Replacing” an old tree is no more meaningful than
replacing an old master. The same applies to all ecosystems. When a trawler
ploughs through biological structures on the seabed, they can take hundreds of
years to fully recover. When a river is dredged and straightened, it becomes,
by comparison to what it once was, an empty shell.
So what
would a slow ecology movement look like? As Henry David Thoreau said, we are
rich in proportion to the number of things we can afford to let alone. To the
greatest extent possible, we should allow our complex natural architectures to
recover. This means keeping trawlers out of all the places farcically listed as
“marine protected areas”, most of which are nothing but lines on the map. It
would mean, in nature reserves, less reliance on grazing by livestock, which
tend to keep living systems in a state of arrested development. It would mean
letting rivers run free.
Wherever
possible, we should allow the trees killed by ash dieback and other diseases to
remain standing. If one good thing arises from these plagues, it could be an
increase in the amount of standing and fallen dead wood, both of which are
crucial habitats. “Salvage logging” – removing dead or dying trees – is one of
the most damaging human activities. Perhaps it also means a general
preservation order for all trees, living or dead, greater than 100 years old:
you would need express permission to fell one. It would mean a new and deeper
respect for the entanglements of nature.
We need to
create today the knurled and wizened ecosystems that only our grandchildren
will see. Restoring the living world means restoring complexity, and complexity
takes ages to develop. So it’s time we began.
George
Monbiot is a Guardian columnist
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