„No Tract of Land is too small for the Wilderness Idea.“ 

(Aldo Leopold)

At Green City Solutions, we believe that nature must be brought (back) into the city, and moss must be a part of it!

Moss in the City

The inconspicuous plant can both actively combat climate change and mitigate its consequences. In our intelligent air filters CityBreeze, CityTree and WallBreeze, mosses bind CO2 and convert it into oxygen via photosynthesis. In addition, mosses filter climate-harming substances such as soot particles. The small plant has the natural ability to bind and metabolize fine dust. Moreover, mosses cool the ambient air by evaporating water on their enormously large leaf surface.

Therefore, moss is at the heart of our intelligent and natural air filters. These combine the natural capabilities with state-of-the-art Internet of Things sensor technology, active ventilation and irrigation technology. But it is not only the moss contained in our smart biofilters that helps make urban spaces more livable and resilient.


Biodiversity and the conservation of biological diversity has been one of the central topics of nature conservation for more than 30 years now (sources: UN Environment Programme, Federal Agency for Nature Conservation). In this regard, “urban space […] plays a key role in several respects”: “Urbanization, with its direct and indirect effects, is considered one of the main causes of the global biodiversity crisis” (source). Currently, more than 50% of the world’s population lives in cities, in Germany even about three quarters of the population (source: Environmental Action Germany).

“Due to the increasing use of land by us humans”, biodiversity and species diversity is “now severely threatened” (source). A according to the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), our planet “is even facing one of the largest species extinctions in the history of the Earth, and Germany is also affected” (source). In December 2010, the United Nations (UN) proclaimed the “UN Decade of Biological Diversity 2011 – 2020” to “halt this mainly human-induced decline” (source). Beginning in 2021 and continuing through 2030, the decade’s theme, according to the United Nations, is “Restoring Ecosystems” (source).

Since 1992, the Convention on Biological Diversity (CBD) has been the central environmental agreement and the most important global instrument for the sustainable use of biological diversity on earth. At the end of 2022, the contracting parties met in Montreal, Canada, and committed themselves to a “new framework for biodiversity”. This framework provides regulations to implement the convention by 2023.

In 2021, the German Federal Ministry for Economic Cooperation and Development increased its investment in biodiversity conservation for the first time to 600 million euros. This makes the German government one of the largest donors worldwide for biodiversity conservation (source).

Biodiversity in the City

The diversity of animal and plant species plays a crucial role in maintaining ecological functions in urban areas. Plants contribute to the improvement of air quality, serve as habitats and food sources for various animal species. Conserving biodiversity in cities equally means maintaining the stability of the ecological balance.

The same applies to the regulation of the urban climate. Green spaces and tree population contribute to the cooling of urban areas: They provide shade, reduce heat island effects, improve the microclimate, contribute to evaporation and increase humidity. In this context, adaptation to climate change occurs. The urban microclimate benefits as well as the inhabitants. The existence of nature and biodiversity also has positive effects on the health and quality of life of its residents. Green spaces, parks and natural habitats provide residents with opportunities for recreation, relaxation and social interaction. They create places to meet, increase well-being and reduce stress.

Biodiversity is essential to our well-being. From the air we breathe to the food we eat, we depend on nature to stay happy and healthy, wrote the World Wide Fund For Nature (WWF). That’s why it’s important to protect and restore it.

As Nature and Biodiversity Conservation Union of Germany (NABU, Naturschutzbund Deutschland e. V.) reports, the term “biological diversity” stands not only “for diversity of species, but also for the diversity of habitats and the diversity of available genetic resources that ensure the survival and adaptation of species”, which is why “urban development must not only pay attention” to “creating functional units for human life and economic activity, but also include connected biotope systems for urban nature” (source).  

Even “small ecological niches” provide important habitats and are equally “part of local urban climate improvement” (source).

Increasing Biodiversity with Moss in the City

Contributing to “local urban climate improvement” is also one of our goals at Green City Solutions. Within this framework, our moss filters can contribute to the preservation of biodiversity in addition to air filtration and cooling. As is currently the case in cities like Braunschweig and the municipality of Bestensee near Berlin, our CityTrees are being enhanced with additional greenery, thereby serving as an important element in increasing urban diversity.

The local fresh air zones in Braunschweig are located, on the one hand, on a median strip of a main road into the city and, on the other hand, next to a bus stop at one of the main traffic junctions in the inner city area. The air is thus cleaned where it is polluted and street trees have no place for sustainable, healthy root growth. The seating surface of the CityTrees, which also functions as a water reservoir and foundation substitute, can be partially or fully greened on request.

The surrounding greenery of low-growing perennials, flowering plants, grasses and solitary plants can be visited and used by insects.

Placed in a network, CityTrees can connect distant urban biotopes, helping to preserve the biodiversity of fauna-flora habitats in cities.

In addition to the surrounding greenery, the mosses themselves also play an important role. Although they may seem “small and inconspicuous”, mosses are assumed to hold a relevant position “in the ecosystem in various respects” (source). Swissbryophytes referred to them as ” a small city in a small space” (source), as they provide a “habitat for small and smallest” (source). Moss serves as food and shelter for a variety of insects, including bees, butterflies, and beetles. In other habitats, mosses perform pioneering work regarding soil formation and “prepare the way for the growth of flowering plants”, they are “regulators of the water balance”, peat mosses are “builders of the raised bogs” and thus “contribute significantly to mitigating the greenhouse effect”. (source) The inconspicuous plants serve as bioindicators and building material for the construction of (bird) nests. (source)

Recently, a new potential application for our biofilters in the context of urban biodiversity also emerged: As reported by APA Science, among others, “measuring stations monitoring air quality around the globe […] could be instrumental in documenting the state of global biodiversity” (source). A new analysis in Current Biology found “that the air samples contain environmental DNA (eDNA) from animals and plants – providing a ‘treasure trove’ of previously hidden biodiversity data” (source).

Accordingly, the mossy measuring stations could make a valuable contribution to the documentation of urban biodiversity with their data in the future.