The role of monumental trees in the life of the forest and the planet

It takes many years, sometimes centuries, for a tree to reach the size that grants it the status of gigantic, monumental or remarkable tree. Whatever the chosen name, the truth is that “nature knows what it is doing” when it comes to preserving the biodiversity of forest areas and therefore there is a good reason for such magnificent species.

 Its size fascinates humans, making us feel small and vulnerable when next to them. They are imposing, important landscape landmarks and break records, so large that they remain after centuries of growth and evolution. These monumental trees play a major role in preserving the life of forests. And they are home to many living organisms.

Let’s start by identifying some famous species. In California, for example, lies redwood (Sequoia sempervirens), the tallest tree in the world and around 600 years old, 116 meters tall and nicknamed Hyperion.

In the National Forest of Vale de Canas, in Coimbra, lies the tallest eucalyptus (Eucalyptus diversicolor) in Europe, around 140 years old and 73 meters high, known as Karri Knight.

Still on national lands, we have the olive tree “Oliveira do Mouchão”, in the village of Mouriscas, Abrantes, more than 3,350 years old.  Considered the oldest of its kind in Portugal, its trunk measures three meters and has a perimeter at chest height of 6.5 meters. This millennial tree, which still produces olives, is also classified as a Tree of Public Interest and Monumental Tree of Portugal by the ICNF – Institute for the Conservation of Nature and Forests. Did you know that it takes five people to hug it?

In addition to this, we can find other ancient olive trees throughout the country: the olive tree located in Pedras D’el Rei, near Tavira (see photos below), is a great example. Of great beauty and more than 2,200 years old, it was classified as a Tree of Public Interest in 1984 and a candidate for European Tree of the Year in 2022.

Another example is the Araucaria bidwillii, known for being a tree of giant pines (each can weigh 10 kilograms) containing inside more than 100 huge pine nuts. The largest tree in the country, and one of the largest in the world, can be found in the National Forest of Vale de Canas, rising more than 50 meters above the soil, and in other parks and forests in the country.

Whatever the particular traits of these trees, there is something very important to retain which is the impact of their existence.

In addition to preserving much of the planet’s biodiversity, forests are crucial ecosystems for regulating climate change. More than a natural, renewable and biodegradable raw material, wood is also a privileged deposit of CO2, which trees take from the atmosphere. In turn, it is stored in the wood and in the products originating from it, throughout its useful life. See paper, where each ton retains the equivalent of 1.3 tons of CO2 – and gas with the greatest impact on global warming, accounting for 65% of greenhouse gas emissions.

Forests thus prove to be a natural solution to mitigate the effects of climate change. And what is the contribution of monumental trees? According to an article published in the journal Nature, the carbon uptake of trees increases according to their size as the total area of the leaf increases as it grows. This means that older, larger trees absorb more carbon from the atmosphere.

In addition to their carbon sequestration capacity, trees enter the “water cycle” by capturing water through their roots and, through transpiration, returning it to the atmosphere in the form of steam.

Finally, the vast majority of large trees have an advanced age as already mentioned and, therefore, have accumulated cavities in the trunk and superficial roots, as well as dead branches, which are considered important microhabitats of living organisms.

Did you know that…

Portugal was one of the first European countries to create specific legislation to protect monumental trees and the first law on this dates back to 1914.

Portugal is one of the 18 countries that signed the Green City Agreement, a European pro-environment agreement that aims to encourage the increase in the number of green areas to counter the effects of global warming, through the implementation of urban forests. The goal is to make cities greener, cleaner and healthier by 2030.