From guardian of the Earth to symbol of Christmas: the tree

In this article, we will delve into the magnificent role of one of the most iconic elements of the Christmas season: the tree, an extraordinary living being that is fundamental to our existence. Together, we will explore its essential contribution to oxygenation, climate regulation, and the fight against pollution.

But that’s not all: we will uncover fascinating facts, its extraordinary adaptability, and the deep connection this green giant weaves with our daily lives.

Enjoy the read!

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Those who know me are well aware: I’ve been on a high for several days now. Yes, yes, absolutely, I’m part of  “Nonsochi”   (after all, Chi-ara 😉). For this reason, I’m busy with the Christmas tree lights. I’m carefully moving around it, placing them meticulously to ensure they are all evenly spaced. Then I switch them on and step back: wow! As I stand there, filled with excitement and immersed in the new atmosphere, I can’t help but think about its incredible power. I’m talking about the tree.

Yes, because trees are not just the protagonists of our Christmas traditions. Trees are fundamental to life on our planet! They produce oxygen, regulate the climate, improve air quality, and provide habitats for thousands of species. Without them, the world as we know it could not exist. And yet, we often take them for granted.

How much do you really know about trees?

For example, did you know that there are more than 60,000 species of trees on Earth? According to the  GlobalTreeSearch census, Brazil, Colombia, and Indonesia are the countries with the greatest biodiversity, hosting the most endemic species. However, every year we lose 15 billion trees due to human activity, reducing tree cover to critical levels: today, we have 46% fewer trees compared to 12,000 years ago, when agriculture began to spread.

Currently, about 3 trillion trees survive on Earth. That may sound like a lot, but it is not enough to balance our ecological impact.

For instance, global CO₂ emissions exceed the absorption capacity of existing forests, increasing the risk of irreversible climate change.

And do you know what I love about trees? 

I love their incredible ability to adapt. Most of their roots are found within the top 45 cm of soil, where nutrient and oxygen conditions are optimal. However, some species can do even more. For instance, the bald cypress (Taxodium distichum) develops aerial roots called pneumatophores to "breathe" even in challenging conditions, such as muddy, oxygen-poor soils.

Another surprising fact concerns the reach of tree roots: a mature oak can extend its root system hundreds of kilometers wide. This underground network not only supports the tree but also stabilizes the soil, preventing erosion and landslides (another superpower—step aside, Batman!).

It almost seems like all they’re missing is the ability to talk—and perhaps, they’re even capable of that... 

When it comes to trees, we cannot overlook their extraordinary "communication system". Did you know that some species release volatile substances to defend themselves from pests? For example, apple trees infested by caterpillars emit chemical signals that attract birds, the natural predators of these pests. This phenomenon, known as chemical communication, is an incredible demonstration of resilience and cooperation. 

And don’t tell me you didn’t thank your dad this summer for planting that poplar in the garden where you lay down to recover from the scorching heat. Even in cities, trees play a crucial role in reducing the urban heat island effect, where temperatures can be 4–5°C higher than in surrounding rural areas. Beyond providing shade, trees lower temperatures through evapotranspiration, a process in which they absorb heat to evaporate water from their leaves.

A practical example: it is estimated that a tree cover of 40% in an urban area could reduce summer temperatures by as much as 5°C, unlike building height, which contributes to increasing them. In the context of global warming, these natural solutions are essential for human well-being and climate resilience.

Trees are not only allies against heat but also against pollution. Their leaves capture fine particulates, nitrogen oxides, and sulfur dioxide, improving air quality. However, particulates do not remain on the leaves for long and are later dispersed into the environment by weather conditions. According to recent studies, one hectare of urban forest can remove an average of 17 kg of PM10 per year and 35.7 kg of tropospheric ozone.

In Italy, cities like Milan and Rome are adopting reforestation policies to improve air quality and mitigate the effects of pollution. However, land consumption remains a challenge: cement, asphalt, buildings, and other constructions increase by about 16 hectares per day, reducing the land available for forests.

And then there are trees capable of changing the fate of entire regions. The Great Green Wall in Africa aims to create an 8,000-kilometer belt of forests to halt the advance of the Sahara Desert.

Thanks to techniques like zaï, which retains water in the soil, and the selection of resilient species such as the acacia, the project is already transforming arid lands into green oases. If completed, the Great Green Wall could become the largest reforestation plan in history, improving food security and creating millions of jobs.

And to make it even more fascinating, trees are also capable of recording the stories of the past. Their growth rings not only indicate the age of the tree but also document climatic events like droughts or floods. The science of dendrochronology allows us to reconstruct the climate of centuries ago, providing essential data to understand the evolution of our planet.

They are so talented that we are even studying them to understand if they can improve our physical and mental well-being. The very recent Green Heart Louisville project in the United States has shown that the presence of trees in urban areas significantly reduces levels of hsCRP (C-reactive protein) in the blood, a marker of inflammation associated with cardiovascular risks. 

Participants in the study, monitored over several years, experienced reduced stress, improvements in sleep quality, and lower blood pressure. Isn’t that amazing?

I hope I’ve made you reflect on how deeply intertwined our destinies are. I know you’re already thinking of planting one, and indeed, the National Recovery and Resilience Plan (PNRR) foresees the planting of 6.6 million trees by 2030. However, this initiative is insufficient compared to the over 227 million trees needed to effectively combat pollution and global warming. The key, therefore, remains the preliminary reduction of emissions! 

Now I’m going back to it—it's time for the baubles! To you, I wish a peaceful and warm Christmas.

May this Christmas bring you joy and moments of serenity with those you love.

A wish for 2025? Let’s hope the new year finds us all a little more aware!

“Oh Christmas Tree, oh Christmas Tree,

Your branches green delight us.”

Happy Holidays!

Chiara Pontoni

Sustainability Manager Gesteco