Saturday 17 April 2010

Eucalyptus

Yes, another import, but to be fair you are rather more likely to see Eucalyptus than many indigenous tree species - there are approximately 5 million hectares planted in Brazi!
Why Eucalyptus particularly? Well, Eucalyptus stands are extraordinarily productive, especially in Brazil where the climate is perfect for growth. In fact, Brazil holds the world record, with an astonishing 100 cubic metres per hectare per year! This is not purely a question of climate, Brazil has invested heavily in Eucalyptus forestry, so much so that they are now the worlds largest exporter of both wood and pulp, and even offer production advice to Australia.


The wood is not especially good for construction, but it is excellent for both charcoal (for iron production) and especially paper manufacture. Even so, I'm told that the major newspapers in Sao Paulo cannot get enough paper and have to import.


Of course, for day to day use, Eucalyptus is best known for it's oil, which is not only clears your nose, but is a powerful disinfectant. And, it's flammable. On hot days clouds of oil rise from the trees and it is not unknown for trees to spontaneously explode! Certainly forest fires spread easily and the tree itself is well adapted to regenerate after fire, growing back from it's base (another reason it is useful in forestry).


What does this huge plantation mean for the environment, beyond the obvious loss of natural habitat? Well apart from the increased risk of forest fires, Eucalypts are extremely demanding of water, they can even be used to drain swamps. And, by themselves, they have little to offer the endemic wildlife as there are, sadly, no koala bears in Brazil. A study of bird species found only 8 of the 200 endemic to the Mata Atlantica, though this is partly because the understory is cleared in commerical forests. This included foragers like the Ruddy ground dove (Columbina talpacoti) and our old friend the Bananaquit (Coereba flaveola), who was probably feeding on Eucalyptus flowers, which are very high in nectar.

One way of looking at it though is to consider Eucalyptus as a "crop". If the forest understory is left, quite a few species can still survive, at least in comparison to other "crops" such as sugar cane or maize.It could be worse.

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