This is the old manor house which Jo's daughter and family were thinking of buying, but the estate agent hadn't updated the pictures. |
There was a day last
year, October the 15th, when the sky over southern Britain
turned an apocalyptic orange – we knew that the remnants of a
hurricane, Ophelia, was about to hit us, but it was not until later
on that we learnt that the extraordinary light conditions were the
result of soot from fires in Spain and Portugal. Forest fires on a
massive, and so far unprecedented scale for Europe. Having just spent
a couple of weeks in the affected area, and concerned that there has
been very little publicity about what happened outside the region, I
want to say something about the issue here.
There had already been
severe fires in Portugal in June, and a blog posting of mine then had
discussed them in terms of them being largely the result of extensive
eucalyptus planting. The conditions in October were exceptional:
Ophelia was the most easterly tracking hurricane ever, big storms
rarely go that far south, and the region was tinder-dry after many
months without rain. All of these are indicators of a possible
outcome of climate change.
Words cannot even begin
to describe the scale of devastation, which has had nothing like the
international press coverage it deserves. It looks as if someone has
taken a flame-gun to the countryside. It is possible to drive for
several hours across central Portugal and nearly every area of forest
or trees in villages or in farmland have been burnt. Many houses too,
especially the rather splendid big old abandoned houses which this
country of large-scale rural depopulation is littered with. Some
factories and warehouses too. Parts of the country are like a war
zone. The Avo valley, a steep river valley, once very picturesque
despite the ever-present eucalyptus is now a blackened ruin of a
landscape. All in all, a terrifying presage of what might become much
more common with climate change.
Eucalyptus acted as a
vector for the fires spreading them into areas of pine (also
relatively inflammable) and other areas of woodland. There is very
little deciduous woodland left in central or northern Portugal, and
oddly a lot of oaks loo relatively damaged. Deciduous trees like oaks
and chestnuts are not so inflammable. Indeed where there is deciduous
woodland, it seems as if the fire has not penetrated.
Fire is an important
part of ecologies in many regions and the idea that it is always bad
and damaging is now rejected. Understanding it is vitally important
as to how we manage landscapes and indeed plant gardens.
There are many
'fire-resistant' trees. Eucalyptus however the opposite, as they
appear to deliberately court fire. This is what makes them so
dangerous. I'll try to explain.
Think of Pinus pinea,
the umbrella-shaped Stone Pine of the Mediterranean – its shape is
obviously designed to keep the foliage canopy up and away from ground
fires. Cork oaks are similar, and of course have the amazing
fire-resistant bark which has long been one of Portugal's main
exports. Pinus palustris, the Longleaf Pine of the American South
does not have this shape but gets its foliage up from the ground very
quickly. This latter and its relationship with fire is now recognised
as having been fundamental to a vast swathe of land from North
Carolina around to the border with Texas (most was felled in the late
19th century to make way for slave-grown cotton). Longleaf
dominated its territory, but by leaving a big gap between the ground
and the canopy allowed ground fires to sweep across vast areas doing
little damage to the trees. The regularity of the fires ensured that
there was no build up of fuel – many of these fires were probably
like prairie fires, very superficial. They would however have damaged
many tree seedlings but left the better-adapted Longleaf seedlings.
However it enabled a very diverse grass and wildflower flora to
flourish.
I first heard about
Longleaf when I went to a lecture by Janis Ray at the university of
Athens, Georgia many years ago. I thoroughly recommend her bio –'Ecology of a Cracker Childhood'
and indeed anything
else about this remarkable tree that you can find.
Key to the survival of
all these species is to have small and frequent ground fires. This
makes canopy fires rare, and it these that do the really lethal
damage to mature trees. Pines do not survive, and generally only do
so through their seedlings taking off after a disastrous fire.
Eucalyptus however
seems to deliberately encourage canopy fire. Their bark peels off and
falls off in great strips, leaving a pile of what amounts to kindling
at the base of the tree, with some loose strips leading thoughtfully
up into the canopy of oil-soaked leaves. They are a recipe for the
smallest ground fire leading to an almost explosive canopy fire.
After which they recover, remarkably quickly. Sprouts can be seen
surprisingly far up blackened trees only months after burning. In
other words the trees' burning seems an evolutionary adaptation, that
knocks back other tree species and gives the eucalyptus a competitive
advantage. Just the same as with grasses, which burn easily, but
survive and flourish amongst more seriously damaged woody plant
seedlings.
To add insult to injury, young eucalyptus seem almost unaffected by the fire - presumably the canopy fires sweep over the top of them. I wonder too if the silver foliage they have is somehow fire-proof.
I wrote about the
origins of the Portuguese eucalyptus problem in this posting. Only
to add that I have since found out that Portugal was massively
deforested in the 19th and early 20th century
by a combination of overpopulation and traditional agriculture
linked to a failure to industrialise. Zillions of sheep and goats
roaming the hills eating tree seedlings apparently. That linking of
population issues with unadaptive agriculture and failure to develop
sounds like today's Haiti or Rwanda. That's another story.
Find out more about the
battle against Eucalyptus in Portugal here.
and about similar issues in California here:
3 comments:
The same horror stories around Eucalyptus, pine and also palm trees here. Why are palms often the first and only choice for trees?
Re Portugal's devastating fires and Ophelia: I read John mcphee's "the control of nature" many years ago. The section about the Los Angeles basin, it's geology, fires, rains, and mudslides is so instructive and informative.
Sad to say, the observations (about the inexplicable connections between the fire sites, the following torrential rains--heavier than in adjacent, unburnt areas--and ensuing mudslides) McPhee made seem to have been ignored in the succeeding years, as we are continually treated to sensational news coverage of the "unbelievable coincidences" of pacific storms, fires, mudslides, destruction of life and property. As McPhee noted, meteorologists had no explanation for these "coincidences," which were nonetheless measurable ad observable.
~ Abigail Higgins
I found this article about the fires with eucalyptus trees and i thought it was in tune to your story
https://baynature.org/article/burning-question-east-bay-hills-eucalyptus-flammable-compared/
ome 600 members of genus Eucalyptus dominate forests across Australia. There, the debate isn’t over whether the trees are flammable, says David Bowman, a fire ecologist at the University of Tasmania, but about whether the trees have simply evolved to survive fire, or whether they actually promote fire as a way to snuff out competitors. “It’s an amazing just-so story,” he says of the possibility: “Eucalypts evolved to burn their neighbors.”
It’s clear that fire benefits the trees. “For most eucalypts, fire was not a destroyer but a liberator,” writes fire ecologist Stephen Pyne in his book Burning Bush. Many species of eucalyptus both tolerate fire, hiding from the flames behind thick bark, and depend on it to open their seed pods. Fire often even seems to have a rejuvenating effect on the trees. After a fire, many eucalypt species will sprout epicormic shoots along their entire trunks. In the event that a fire does destroy the aboveground parts of the tree, it can send up new shoots from lignotubers, nutrient-filled organs hidden among its roots.
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