A development consisting of four buildings and a mobility tower requires a substantial amount of wood – around 30,000 cubic metres, equivalent to approximately 20,000 trees. But what exactly is moon wood? 
On a cold winter’s day in the run-up to Christmas, part of the project team set off for Central Switzerland to experience the journey of wood from the tree to the sawn plank.

1st stop: St. Joder in Engelberg Valley

The Engelberg Valley is cold and shady this morning, and it soon becomes clear why the region has the highest density of cable cars anywhere. Steep slopes on both sides of the valley are covered with dense fir forests reaching to the peaks. Harvesting wood using a harvester, as is common in the Swiss Plateau is not possible here. Near Grafenort, a narrow mountain road winds its way upwards, and soon you can hear the sound of a chainsaw. But the trees are not being sawn, as we find out at the assembly point at around 900 metres above sea level, they are being girdled. Stephan Küng, owner of the eponymous timber construction company, explains to the assembled group what moon wood is all about.

Moon wood or lunar phase wood is harvested only on a few days in winter, just before the new moon. At this point, it contains the least amount of sap and is therefore avoided by pests. In addition, it weighs less and has a reputation for being particularly hard, stable and easy to process later. The same effect can be achieved through girdling. A special attachment on the chainsaw is used to cut a notch about four centimetres deep all the way around the root. This interrupts the water-bearing layer and the tree releases the remaining moisture through its needles. Around three months later, the wood can be felled. “It’s more stable”, says the expert. “It hardly deforms as the humidity changes and no longer needs to be dried afterwards. This saves a lot of energy and time.” And the lower weight is also an advantage: It reduces the number of lorry trips required, even if they are only short. In addition to the type of forest management, the transport distance is the key factor which determines whether wood is sustainable or not.

A tree is then felled after all. A 115-year-old spruce, symbolising the start of the project. On the way down to the valley, we imagine what the landscape looked like here back in 1910. And we are delighted to see that we are not simply clearing industrial wood here, but using a conscious and highly respectful approach to working with nature and the environment. The foresters only fell large, sturdy trees, and the logs rarely exceed 500 square metres. This ensures that the forest remains an ecologically valuable habitat. The parts of the tree that cannot be used for construction have a short journey ahead. In the future, they will provide heat in Engelberg’s heating systems as wood chips. And the journey that the wood will make later is also short. Impressively short.

2nd stop: Rothenburg near Lucerne

Just over half an hour later, we arrive at the sawmill where the wood for the floors, walls and ceilings for the BAMA Zug project is being processed. Thousands of tree trunks destined for Baarermatte are piled up. Each one is six metres long and all were cut last winter, because it would be impossible to harvest the required amount of wood in one single winter. Finally, wood from three winters will be used at Baarermatte. 
The boss and his two employees process the logs into planks. Despite the support of state-of-the-art machines, a lot of manual work is still required. The group is watching with interest. It is a quiet tribute to a dying craft. In 2024, only three apprenticeship contracts for "wood industry specialists" were conclud-ed in Switzerland. 
The planks are then transported to Alpnach, a journey of just over 20 minutes. In the carpenter’s shop, the planks are then joined to form components and elements using dowels, without the use of glue. And the transport route from there to the construction site at Baarermatte is just over 40 kilometres long.

3rd stop: Cham

At the edge of a large gravel works in Cham, you can already get an impression of what the BAMA Zug will look like in the future. Here, a mock-up has been set up, a show building measuring around 30 square metres that has been constructed and finished exactly as planned. The project team consisting of architects, planners and representatives from Allreal inspects the details, colours and surface finishes with keen interest.

What remains to be said about the excursion is that sustainable construction can be much more than just replacing concrete with wood and keeping transport distances short to reduce CO₂ emissions. The greatest added value comes from aligning the three sustainability factors of environment, social and corporate governance along the entire supply chain – from forest owners to carpenters on the construc-tion site. This means using durable and recyclable materials, negotiating fairly, using regional resources and supporting local craftsmanship.