🌿 What Are Lichens?

Lichens are a remarkable example of cooperation in nature — two completely different organisms living together, supporting each other to survive some of the harshest conditions on Earth. They form through a symbiotic relationship between:

• a fungus (which provides structure, protection, and habitat),
• and a green alga or cyanobacterium (which performs photosynthesis and produces food).

This partnership isn’t just a simple “cohabitation” but a deeply integrated relationship. Together, they form a completely new organism with traits neither could have alone.

Lichens are neither plants, animals, nor simple fungi — they belong to their own kingdom, telling a living story of adaptation and balance. They appeared over 400 million years ago and have managed to colonize places where few other life forms can exist: glaciers, dry rocks, abandoned roofs, or tree bark in city forests.

🌬️ Why Are Lichens Important for Air Quality?

Lichens have no roots. They don’t feed from soil. They don’t absorb water through stems or leaves. Everything they need for life — water, light, minerals — comes directly from the atmosphere.

This makes them uniquely sensitive: they are in constant, direct contact with the air. If the air is clean, they thrive, grow, and reproduce. If the air is polluted with toxic gases, heavy metals, or industrial dust, they start to suffer — changing color, drying out, or disappearing altogether.

Moreover, different lichen species react differently to various pollutants. Some are sensitive to sulfur dioxide, others to nitrogen oxides or heavy metals. So by simply observing which species live in an area, we can understand the air quality there.

Lichens thus become natural “bio-sensors” — 100% organic, completely free, and remarkably precise.

📍 Why Do We Use Lichens in Lichenary?

The Lichenary project has a clear mission: to turn young people into explorers of the air. We want every participant to learn how to observe the nature around them, identify the invisible signs of pollution, and actively contribute to environmental understanding.

We use lichens because they:

• help us measure air quality without complicated devices;
• can be identified with the naked eye after some basic training;
• provide relevant data from any environment — city, village, forest, or schoolyard;
• allow us to build a living, real-time map of the air with the community’s help.

Plus, they’re stunning: each species has a unique shape, color, and texture, like hidden jewels on tree bark.

🔍 What Types of Lichens Do We Analyze?

In Lichenary, we focus on three main groups of lichens, based on their form and pollution sensitivity:

1. Crustose
   • They appear completely stuck to the surface like a crust.
   • They cannot be separated without breaking.
   • Pollution-tolerant.
   • Indicate medium to high levels of pollution.
2. Foliose
   • Have small, visible leaf-like structures partially detached from the surface.
   • Moderately sensitive to pollution.
   • Their presence indicates acceptable air quality.
3. Fruticose
   • Look like small bushes or corals.
   • Highly sensitive to pollution.
   • Their presence signals very clean air.

🧭 How Do We Identify Them?

You can find lichens:

• on tree bark (preferably in parks or urban forests),
• on rocks and stones,
• on old walls, roofs, or monuments,
• in damp, shady, and unpolluted areas.

Most often, lichens grow better on the north side of trees, where humidity lasts longer.

Every team or volunteer in the project will learn how to photograph lichens, observe their shape, color, and position, and use simple identification guides.

🤝 Join the Lichenary Mission!

We encourage you to become a citizen scientist and help map the air quality in your community through lichens. By observing, reporting, and sharing your findings, you contribute to a healthier environment for everyone.

Let’s explore, learn, and protect the air together!