N°66 — João and the Green Giants

Lousada, 21st January 2026,

Trees play an essential role in my life, especially giant trees. They influence my work as a biologist but also the way I see things and the way I speak. They guide my travels: I travel around by car with my dog to observe them. It’s a kind of hobby, or perhaps an obsession, that I try to propagate around me.

I began recording the ‘gigantes verdes’ (green giants) in the region of Lousada, in northern Portugal. ‘Green giants’ are trees with a circumference of at least one and a half metres at chest height, approximately 1.3 metres high. So that’s trees which an adult wouldn’t be able to wrap their arms around!

Trees are often only valued in terms of how much wood they represent. And yet they have so much more to offer: oxygen, shade, cooling, tranquillity, a habitat for wildlife and carbon capture. However, in Portugal, very little importance is given to trees when they’re alive, and even less when they’re dead. Portugal is second to bottom, in terms of the amount of dead wood available in its forests, in Europe. Which is a real problem, because 70% of the species living in this environment depend on dead wood for their survival!

Nowadays, lots of companies and individuals are worried about their carbon footprint and are focused on the idea of offsetting it. The problem is that most offsetting projects boil down to planting, planting, planting… But the majority of trees planted don’t make it past the age of ten or will only make a real difference in 40, 50 or 60 years. And we don’t have that much time to find a solution.

Green giants, meanwhile, hold 78 times more carbon in their wood than a ten-year-old tree. Each year, the amount of carbon absorbed by a green giant tree is equivalent to the total amount absorbed by a tree in the first fifteen years of its life. For the good of our society, it is therefore preferential to focus on preserving these giants to planting new ones.

Here in Lousada, we’ve recorded around 7,500 green giants. But the figure varies. During the pandemic, I began analysing our data to understand what was happening and found that these trees were disappearing at a rate of 2% per year.

For the landowners, it’s more financially advantageous cut down their trees. The price per square metre is higher when it can be used to build a house or grow crops than if it’s forest land.

Everyone benefits from the green giant forests, the problem is that it’s left down to individuals to look after them. Landowners are required to keep them clean, prevent fires, and let us walk on their land for free, without getting anything in return. At Verde (the organisation João created, editor’s note), we decided to work with these owners. We offer them 10-year contracts, during this period, they can’t cut down green giant trees, and we pay them or help them to preserve the forest.

Money is a universal language. When we don’t speak the same language, we can’t engage in conversation and change things. If we can make preserving trees profitable, then we can begin to build a relationship, which may lead our interlocutor to understand the usefulness of trees and their preservation. In this sense, what we are doing is a form of resistance.

João