Ljubljana chooses climate-resilient lime trees in the historic city centre

In 2023, lime trees were planted along Ljubljana’s waterfront in TreeParker soil cell systems. The trees are growing healthily within the paved area and provide increased shade and cooling. In this way, the project enhances both the liveability and climate resilience of the historic city centre.

Ljubljana is the charming capital of Slovenia. The city combines a fairy-tale atmosphere with a vibrant café and cultural scene within a compact, walkable and green city centre. It is even considered one of the greenest capitals in Europe. The historic city centre along the River Ljubljanica attracts thousands of residents and visitors every year, but like many urban centres, this location also faced a challenge. How do you create sufficient space for healthy trees in a heavily paved area without compromising the heritage appearance of the surroundings?

During the redevelopment of the waterfront in 2023, a sustainable tree pit solution was chosen. The trees were provided with an optimal tree pit within the paving using the TreeParker soil cell system. This created a load-bearing rooting space beneath the paving where tree roots can develop optimally without causing damage to the surface.

The choice of lime trees fits seamlessly with the history and identity of Slovenia. For centuries, the lime tree has served as a gathering place for village communities and important meetings. The tree symbolises connection, solidarity and local traditions. By incorporating this characteristic tree species in the heart of Ljubljana, not only is urban greening enhanced, but an important cultural element is also reintroduced into the public space.

Trees in urban areas often face a lack of rooting space, soil compaction, oxygen deficiency and drought stress. The TreeParker soil cell systems provide an integrated solution to these challenges. Beneath the paving, sufficient rootable volume is created while the structure can withstand heavy traffic and usage loads. The trees are also equipped with irrigation and aeration facilities, ensuring that water and oxygen reach the root zone directly. Bamboo trunk protectors have also been installed. This natural and breathable material protects young trunks from sunscald and other forms of damage.

During a visit to the site in the summer of 2025, it became clear how successful the approach had been. The trees have developed healthy crowns and have now become a prominent part of the streetscape. We spoke with staff from the restaurant whose terrace is situated among the trees. They told us that the trees had doubled in size since the previous year. Whereas visitors once sat in the blazing sun, they can now enjoy pleasant cooling and natural shade.

This project demonstrates how innovative tree pit design can contribute to an attractive, climate-resilient public space. Thanks to the TreeParker system, the trees have sufficient underground rooting space, while the paving remains stable and the historic character of the area is preserved.