Denmark’s tallest timber tower: Future of circular, low-carbon architecture

In Denmark’s second-largest city, a former industrial harbor has been transformed into a vibrant mixed-use neighborhood. At its center stands a roughly 260-foot-tall building that tackles one of architecture’s toughest challenges: whether high-rises—often seen as some of the most carbon-heavy forms of construction—can be redesigned as circular, low-emission systems.

Recently completed, TRÆ is now the tallest timber building in the country. It places mass timber at the core of a broader effort to rethink how materials are sourced, reused, and assembled across its 3.62-acre site. The project serves as a test case for how dense urban developments might move away from carbon-intensive construction methods.

Its name reflects its concept. In Danish, “træ” means tree, timber, and three, pointing to the building’s natural material focus, environmental goals, and its composition of three connected volumes. The design features rounded towers that rise from a compact footprint, maximizing natural light while creating a striking presence along the waterfront. The tallest tower reaches 256 feet, accompanied by two six-story structures. Together, they use cross-laminated timber slabs and glulam columns, supported by concrete cores—a hybrid approach that balances sustainability ambitions with structural and regulatory requirements.

Rather than appearing as a single monumental structure, the three-building layout encourages openness and movement. A gently curved pedestrian bridge connects the site to Aarhus’s developing elevated walkway, while active ground-floor spaces and a winding exterior path invite people to pass through and engage with the area.

Following Lendager’s principle of “form follows availability,” the project treats the building as a dynamic system of materials rather than relying on a fixed palette. CEO Anders Lendager frames this approach as a response to global resource challenges, seeing waste as an opportunity rather than a limitation.

A standout example is the reuse of retired wind turbine blades, which have been cut and repurposed as exterior sun-shading elements. Integrating them required extensive fire testing and façade redesigns to meet safety standards, highlighting the challenges of turning discarded materials into functional building components.

The project also connects environmental goals with social impact. Residents experiencing homelessness have been involved in aspects of site activity and upkeep, and the development hosts volunteer programs that provide meals for families in need. This reflects a broader belief that sustainability must include human life and community, not just environmental performance.

Notably, the team chose not to pursue formal sustainability certifications. Instead, they followed a flexible, value-driven approach that allowed environmental strategies to evolve alongside design and technical development—prioritizing real outcomes over checklist-based systems.

Compared to a conventional concrete building, TRÆ achieved a 26% reduction in CO₂ emissions. Of that, 21% comes from the timber-focused design, while 5% results from the use of reclaimed materials.

Ultimately, the project reimagines what is possible across the construction value chain. For Lendager, developments like TRÆ should act as guiding examples for the industry demonstrating both the potential for change and the urgency of rethinking how we build.