Saturday 21 October 2017

Wildfires kill 43 in Portugal.

Forty three people have been confirmed dead and a further 71 have been injured as a series of wildfires have swept across northern and central Portugal this week. The majority of those who have died have done so in their cars, trying to escape from raging forest fires on country roads. Over 600 separate fires have been reported, the second major outbreak of such fires this year, after a series of fires in June killed 64 people and injured over 250 more in the central Pedrogao Grande Region. At least four people have died in similar fires in neighbouring Spain this week.

 Forest fire in Portugal earlier this week. APTN.

The fires are reported to have a number of different causes, including in some cases deliberate arson, and have been made much worse by both a prolonged heatwave in Portugal. which has dried out vegetation making it vulnerable to fires, and high winds associated with Hurricane Ophelia which have fanned the blazes and helped them to spread rapidly. However the fires appear to have been worst not in areas of natural woodland, but in the countries extensive plantation forests (i.e. forests of planted trees grown for the value of their timber), with the most severe fires occurring in areas of Pine and, particularly, Eucalyptus cultivation.

Clouds of thick smoke from the forest fires above the town of Marinha Grande in the Leiria District of Portugal earlier this week. João Pinto/Severe Weather Europe.

Eucalyptus, or Gum Trees, are fast growing members of the Myrtle Family, Myrtaceae, native to Australia but now grown extensively for their timber in many other parts of the world. They are valued for their fast growth, enabling them to produce much timber quickly, However they dominate ecosystems in which they become established, causing a variety of problems both for native plants and animals, as Human residents. The trees produce large amounts of volatile terpanoids which suppress the growth of other plants, and consume large amounts of water, lowering the water table in areas where they become established. The trees also shed branches regularly, as well as leaves and strips of bark, creating a dry environment littered with dry plant material where wildfires quickly become established. The terpinoids in the wood of Eucalyptus cause these forests to burn readily, typically at a tempereature about 30 °C higher than other forest fires, which can kill specie such as Oak, which can often survive fires. This increases the ecological dominance of the Eucalyptus, as, while the trees are killed by the fires, the seed pods can survive and rapidly germinate after fires, which since the trees grow quickly, enables them to quickly claim the newly available land.

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