Let’s go on a treasure hunt. The treasure is in the forest. We know that, as the sun rises, the trees begin to do their work. They turn carbon dioxide (CO²) into oxygen, the elixir of life.
Where is the treasure buried?
Bear in mind that, in the Iberian Peninsula, 1.5 million hectares are covered in forests of eucalyptus, to be turned mainly into office paper. In Portugal, (92,000 km²) we have eucalyptus planted on one million hectares. This amounts to 10,000 km², or 12% of the national territory. To visualise what this means, imagine a line connecting Lisbon to Montemor-o-Novo, Abrantes and Leiria. Mark this line on a map of Portugal, our treasure map, and fill in the resulting square in red.
In Spain (515,000 km²), a country five times larger than Portugal, the total area planted with eucalyptus is only equal to half of that in Portugal, that is, exactly 500,000 hectares. There are 5,000 km², in other words the area of the whole region of Madrid, an area measuring 50 by 100 km, less than one percent of Spanish territory.
How many hectares are there in a square kilometre?
Why are there more eucalyptus trees in Portugal than in Spain?
Do you want the good news first? Almost all of us know why there are more and more extreme weather conditions. They are a consequence of our lifestyle and the carbon dioxide we emit into the atmosphere during the 52 weeks of each year. On average, a German resident pollutes the atmosphere every year with eleven and a half tons of CO2; a resident of the United Kingdom is responsible for ten tons; and a Portuguese resident emits on average seven tons of CO2 in the 52 weeks of each year. These emissions are the result of travelling by car and plane, consumption of meat, sausages and butter and electricity and the purchase of clothes from the Far East, etc. The ten million inhabitants of Portugal produce 70 million tons of CO2, a very good figure for a country with an area of 92,000 km², or about 600 km by 154 km, which places Portugal in the lower third of the table of Europe’s carbon emitters. And Lisbon, the capital, is this country’s main polluter.
How many kilos are there in a ton?
What weighs more, a ton of CO2 or a ton of oxygen?
And now for the bad news. In the south of Portugal, a forest has just finished burning for a whole week in a fire caused by a high voltage cable that ignited a tree in a eucalyptus forest. Really? Eucalyptus catches fire easily because it contains a lot of oil. About 30 million trees were burned, both young and fully grown, amongst them many cork-oaks, stone pines and much vegetation of great value. There were many animals that succumbed to the flames: for example, 60 million bees from 3,000 hives. The smoke generated during the seven days, in an area of 280 km² (10km x 28km), was equivalent to the emission of carbon dioxide from ten million inhabitants for 52 weeks. A hell on earth, a true catastrophe.
Why do most fires start in eucalyptus forests?
Thanks to the fires, Portugal succeeded in putting itself at the top of the list of Europe’s carbon-emitting countries, surpassing even Germany and the United Kingdom. Now, on average, all Portuguese are responsible for at least 14 tons of CO2, although pulp producers are the real culprits. And now? The year has not yet come to an end. This figure could still get worse, with more air being polluted by forest fires and, at the same time, the area which is forested, which we need in order to turn CO2 into oxygen again during the coming years, is disappearing. Therefore, anyone who plants indigenous trees – such as forests of cork oak and chestnut – is doing the right thing.
How many trees (cork trees, chestnut trees, etc.) would have to be planted in the burned areas, per head, during the winter over the next five years, so that in 2023 we could again reach the figure of only seven tons of CO2 per head?
In order to do this, we must realise that each tree that is planted transforms 10 kg of carbon dioxide into oxygen in its first year of life, in the second year 15 kg, in the third 22.5 kg, in the fourth 33.75 kg and in the fifth 50.625 kg. And only one in three trees survives until it is five years old.
In Corte Grande, Monchique, there is a 2,000-year-old cork oak. How much CO2 has this tree turned into oxygen in the course of its life?