 |
| A typical cultural landscape in Coimbra district. The distant hills would be about 90% eucalpytus |
Just had two weeks in central Portugal, near Coimbra. The Iberian peninsula is not somewhere I am that familiar with, but would increasingly like to be. It is home to some 6,000 native flowering plant species, scattered over an amazingly wide range of habitats. A brief foray into Spain last spring made me feel very optimistic about spending more time in the region. Central and northern Portugal however been a bit of a reality check. It seems to be home to one of the biggest accidental experiments in ecology I have ever seen. One which looks disastrous and which has had amazingly little publicity, at least outside the country.
 |
| The trees in the rear include cork oak, some pine but also the characteristic cones of middle-aged eucalypts. The trees appear in many village contexts not just in formal plantations in the hills |
The issue is Australians. Not individuals I hasten to include, but eucalyptus and Acacia dealbata - the familiar mimosa and Acacia melanoxylon. And a fresh Zealander - Pittosporum undulatum, and more and more the South North american Cortaderia selloana - pampas turf. I have, as much of you may well be aware, often been fairly sceptical about a lot of the currentdiscussion of intrusive aliens. I've always felt that folks in Britain who fret about impatiens or Japanese knotweed have hardly any notion of the damage that basically intrusive aliens can do; and that lots of 'invasives' are in fact not too bad. Increasingly there is certainly data that alien varieties may also play a good role in the introduction of book ecosystems. Portugal is an excellent exemplory case of where things can go really really incorrect, but also precisely how intricate these issues are.
To begin with the deliberately multiply alien, the eucalyptus, mainly E. globulus. Nearly every vista in your community between your mountainous east and the shoreline, north of Lisbon, that people drove through included it, in great volumes, the distinctively bunchy development of the outermost branches being specifically conspicuous in silhouette. Virtually all the hillsides are protected with it - practically all planted as a forestry crop for the newspaper pulp industry, though it also offers some capacity to multiply by seed too. The storyplot is that a lot of this region has granite or other acidic soils, and is also not much best for the pastoral agriculture that certain might expect in hilly parts, or indeed for cork oak, which really is a major form of land utilization in the warmer and much more calcareous south that your tree prefers. Historically, these hillsides were dominated by oak and chestnut but ages of deforestation led to them being protected in scrub: gorse, heathers, cistus and suchlike. Financially pretty ineffective. Pine was often planted or propagate naturally. But through the 20th hundred years eucalyptus was launched and marketed under the Salazar program (always nice to truly have a fascist dictator at fault!). The newspaper pulp industry carries on to market planting the tree. The effect can be an oppressive monoculture, which with the decrease of the pulp industry (now moving to SOUTH USA), is likely to be increasingly worthless. To state nothing at all of the fireplace risk, posed by this infamously inflammable tree. A eucalypt fireplace can turn complete scenery to ash.
Eucalyptus is a questionable crop. One can't blame poor rural locations for attempting to make money using forestry. And in reality in conditions of the top environmental picture it really is a very important thing. The huge area under the tree here will need to have soaked up plenty of CO2,done much in reducing ground erosion and keep water in the bottom. There's a widespread notion in a lot of the earth that the trees and shrubs dry the ground out, however in fact there exists little evidence that is the situation. In inadequate regions their occurrence can in fact help protect indigenous forests when you are a superior way to obtain firewood and timber, e.g Bolivia.
Eucalyptus plantations have been accused to be 'renewable deserts'. This isn't necessarily the truth either, as from what I've observed in most unmanaged plantations is the fact among older trees and shrubs there is intensive undergrowth by means of gorse and heather or bracken (american Europe's main intrusive non-alien). The web that the trees and shrubs themselves do not support any biodiversity, unlike indigenous pines or better still, oak. Among their most detrimental aspects is they are pretty much indestructible; dropped them or shed them plus they simply pop again from the bottom, getting way before any pine or oak which can contend with them. Planting them has been an almost irrevocable decision. The effect is a lifeless inexperienced coating over virtually all the hills. It really is as if the united states has agreed upon a Faustian pact with a malign fairy, who decided to reforest it, but with a renewable monster that may never disappear completely and facilitates no life.
To begin with the deliberately multiply alien, the eucalyptus, mainly E. globulus. Nearly every vista in your community between your mountainous east and the shoreline, north of Lisbon, that people drove through included it, in great volumes, the distinctively bunchy development of the outermost branches being specifically conspicuous in silhouette. Virtually all the hillsides are protected with it - practically all planted as a forestry crop for the newspaper pulp industry, though it also offers some capacity to multiply by seed too. The storyplot is that a lot of this region has granite or other acidic soils, and is also not much best for the pastoral agriculture that certain might expect in hilly parts, or indeed for cork oak, which really is a major form of land utilization in the warmer and much more calcareous south that your tree prefers. Historically, these hillsides were dominated by oak and chestnut but ages of deforestation led to them being protected in scrub: gorse, heathers, cistus and suchlike. Financially pretty ineffective. Pine was often planted or propagate naturally. But through the 20th hundred years eucalyptus was launched and marketed under the Salazar program (always nice to truly have a fascist dictator at fault!). The newspaper pulp industry carries on to market planting the tree. The effect can be an oppressive monoculture, which with the decrease of the pulp industry (now moving to SOUTH USA), is likely to be increasingly worthless. To state nothing at all of the fireplace risk, posed by this infamously inflammable tree. A eucalypt fireplace can turn complete scenery to ash.
Eucalyptus is a questionable crop. One can't blame poor rural locations for attempting to make money using forestry. And in reality in conditions of the top environmental picture it really is a very important thing. The huge area under the tree here will need to have soaked up plenty of CO2,done much in reducing ground erosion and keep water in the bottom. There's a widespread notion in a lot of the earth that the trees and shrubs dry the ground out, however in fact there exists little evidence that is the situation. In inadequate regions their occurrence can in fact help protect indigenous forests when you are a superior way to obtain firewood and timber, e.g Bolivia.
Eucalyptus plantations have been accused to be 'renewable deserts'. This isn't necessarily the truth either, as from what I've observed in most unmanaged plantations is the fact among older trees and shrubs there is intensive undergrowth by means of gorse and heather or bracken (american Europe's main intrusive non-alien). The web that the trees and shrubs themselves do not support any biodiversity, unlike indigenous pines or better still, oak. Among their most detrimental aspects is they are pretty much indestructible; dropped them or shed them plus they simply pop again from the bottom, getting way before any pine or oak which can contend with them. Planting them has been an almost irrevocable decision. The effect is a lifeless inexperienced coating over virtually all the hills. It really is as if the united states has agreed upon a Faustian pact with a malign fairy, who decided to reforest it, but with a renewable monster that may never disappear completely and facilitates no life.
 |
| Mimosa - notice how closely packed these young trees are - they stay like this with little competition between each other, suppressing all other plants |
Worst still are the uninvited aliens, the escapees from ornamental cultivation which in the moist mild climate are seeding and spreading at an incredible rate. Mimosa is a particular menace in the central part of the country. It is the perfect example of the worst kind of invasive alien: rapid-growing, rapid-seeding, nitrogen-fixing and almost totally suppressing all other plantlife. Talking to locals in the area about Lousã it appears that in the last ten years they have spread along roads and streamsides to form a kind of foreground to the eucalyptus. They root into cracks in rock, into banks, over streep, into established maquis vegetation, and then grow incredibly densely. The shade they cast is so dark almost nothing will grow beneath them, killing off entire ecosystems. In many circumstances, these short-lived pioneer species would be replaced in due course by longer-lived canopy trees but there is so little here to seed into them that that is simply not going to happen. The danger is that the tree will become self-perpetuating, smothering what is currently the main refuge for much native vegetation along the eucalyptus forest margins.
 |
| The bio-desert beneath a mimosa canopy |
Environmental activists have long been warning about eucalyptus. There does seem to be a growing awareness, but once the tide of opinion has turned, it is going to be an almost superhuman struggle for a not very wealthy country to manage this gigantic and multi-faceted problem.
Links:
https://www.facebook.com/Floresta-Portuguesa-Sustent%C3%A1vel-Sustainable-Forests-for-Portugal-345039065588647/
Links:
https://www.facebook.com/Floresta-Portuguesa-Sustent%C3%A1vel-Sustainable-Forests-for-Portugal-345039065588647/
0 Response to "The Eucalyptus and Mimosa Big Problem in Portugal and Australia"
Post a Comment