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Eco123 Revista da Economia e Ecologia
Saturday 20th July 2024.
Do you have to love nature to be able to protect it? Or is it enough simply to calculate the value of a forest in economic terms? The attitude that people have towards the forest, towards invasive tree species and the risk of forest fires arising from the large-scale cultivation of eucalyptus, explains the ethical rationale behind the creation of the institution responsible for nature conservation in Portugal: the Institute for Nature Conservation and Forests (Instituto da Conservação da Natureza e das Florestas – ICNF). Only two percent of the forested land in Portugal belongs to the state, while 98% is privately owned.
It took me three decades to become involved with the ICNF and, since then, I have observed it closely, questioned it and learned to appreciate its work. Not only in Monchique (Faro), but also in many other districts from the north to the south of Portugal, where forest fires have raged and invasive tree species have proliferated explosively. All it takes is for one acacia tree to scatter its fire-resistant seeds over the landscape during a forest fire, thereby guaranteeing its survival. Acacias and eucalyptus trees love fire.
We are talking about Australian acacias and mimosas, which have been steadily displacing native tree species in southern Portugal since 2018. The term ‘displace’ is a thoroughly euphemistic description of what is actually happening. These invasive tree species, which are native to Australia and were first brought to Portugal in the 1930s, can destroy entire groves of mature cork-oaks, chestnuts, olive trees and citrus fruit trees within the space of less than five years. They completely ruin the diversity of the forest: if left unattended, they will attack and destroy the roots of the native tree species growing within their immediate vicinity (spread by wild seeds). Acacias and mimosas will frequently join forces to ‘kill’ an apricot tree in the garden, a cork-oak tree or even entire orchards of orange trees…
If you want to get rid of them, you have to develop a strategy and completely uproot the tree. Caution is the order of the day.
In places where these water-intensive invasive species are allowed to grow unhindered and there is no resistance to their spread, their roots reach deep down into the ground incredibly rapidly. All over the Monchique mountains, the water table has been sinking lower and lower, and many streams have dried up.
Not only do these trees lay down deep roots, but they can also grow in a shallow-rooted fashion. From one side of the road, their roots spread beneath the tarmac surface to the other side, where they continue to grow vigorously. At a pace that has never been seen before in Europe. That’s why we generally don’t recognise the danger posed by these tree species, preferring instead to enjoy the yellow flowers of the mimosas in winter…
Acacias and mimosas have also crept into our new botanical garden in Monchique. And it was while I was gardening that I discovered the Internet of the forest: the invasive trees. Because invasive tree species interconnect with one another via their roots; not only do they exchange food, but also information. I am therefore fascinated by the policies adopted by the state and the local authorities responsible for nature conservation, seeing how powerless they are in the face of the invaders. For a long time, they tried to ignore the acacias and mimosas. The forest is only important in Portugal if you can make money from it. The ignorance of the authorities has given the invasive tree species a head start, which some landowners are now trying to compensate for by bringing out their own heavy artillery. Now, after six years of inaction, they are working with chainsaws and brush cutters, with excavators and, if necessary, bringing into play the entire machinery of a municipality. What have they achieved so far? The invaders are not being eradicated – no – the more they are fought against, the more resistant they become, and the more groundwater they extract from the soil. Respect. The invaders are in competition with humans and are becoming a serious threat to them, because water is becoming scarcer – and not just for gardens. The acacias are stealing people’s drinking water. This is now a serious problem and not just simply a subject for discussion.
The conventional chainsaw is used to fell entire eucalyptus monocultures, which are then transported to the factory and processed into paper, subsequently growing back on their own. But this weapon scares neither acacias nor mimosas. They grow back even faster and extract even more water from the soil. The forests are filled with invasive tree species that have been growing there since August 2018; these are due to become a field of rubble following the deforestation process undertaken in July and the summer of 2024. Currently, the land here gives the impression that tanks have been engaged in a brutal battle on a military training ground. Yet, this is only the first plot of land in Caldas de Monchique, and it is not even ten hectares in size.
I realise that linear human thinking is hopelessly inferior to the circular thinking of nature. The main actors have already lost the first battle to the invaders in their war against nature. They just don’t realise it yet. We should be protecting nature and the forest. But we humans are still far from achieving this. The question is, how can we get rid of the acacias and mimosas without damaging the rest of the forest? After all, the soil that has been turned into ruts by the caterpillars and excavators dries out quickly in the summer heat and is carried away by the wind. Naturally, the end result is erosion and only the rocks remain. No native tree species will grow on these rocks, even though the plan is to plant them there in the rainy season next winter.
Before turning on an excavator, a brush cutter or a chainsaw, how about switching on your brain first and thinking about the methods that could be used to stop the invaders? Because there are groups of conservationists all over Portugal showing us how the ICNF and many municipalities could deal with the danger. All the ICNF has to do is connect to the internet and find out more: https://www.invasoras.pt. Sometimes just a small but powerful pocketknife can minimise the number of invaders…
I will tell you all about this in the second part of my report. I also contacted the ICNF and visited them in their offices near Lagos to find out what the future holds in store for nature conservation in the Algarve. I will inform you about this too, in the next issue, next Saturday.
