Hardwood is the wood of deciduous trees, that is of trees with leaves.

There many different types of wood – about 25,000 worldwide – each of which has its own specific properties. The two major types of wood are hardwood and softwood. Hardwood and softwood are differentiated because of their chemical structure. Hardwood comes from deciduous trees, softwood from conifers.

The two types of wood are largely similar in composition (see table), but due to its structure, hardwood is generally heavier, firmer and harder than softwood. Typical hardwoods include maple, birch, beech, ebony, oak, alder, ash, aspen, cherry, linden, poplar, walnut, white beech and tulip tree. Tropical wood normally refers to the heartwood – the darker inner part of a tree trunk – of tropical hardwood species including teak and mahogany. Softwoods, on the other hand, include spruce, fir, larch and pine.

The timber industry is having to make considerable adjustments as a result of the enormous change in the distribution of tree species in forests. Although forest maintenance is making increasing quantities of hardwood available, very little of it is currently used sustainably. Instead, it is all too often simply burned or used to make products with a short service life. This happens because of the perceived disadvantages during processing (due to the hardness of the material), the longer and more expensive drying process, and the poor dimensional stability of hardwood products. We have to move away from this wasteful approach. The promising properties of hardwood can lead to the optimization of existing types of engineered wood as well as to completely new products.

Raw materials obtained from agriculture and forestry, such as wood, are renewable, but their availability is limited. Added to which, sustainable and resource-efficient use is essential as these sectors have a negative impact on the climate and the environment. Cascade use requires natural materials to be initially used in durable and repairable products to allow them to be recycled as long as possible. In other words, it is the reuse of a raw material over several stages. This approach can achieve economic benefits while reducing pollution and greenhouse gas emissions, cutting costs and increasing added value.

Hardwood – primarily oak – played a central role in building construction well into the 18th century. It was only as a result of population growth and deforestation that softwood gradually became accepted as a substitute.

Now, however, the worldwide boom in timber construction and its rapid development is resulting in demand for new products. This puts the focus on the ever-increasing proportion of hardwood species in European forests. Hardwood materials can make a significant contribution here, as they enable lean, esthetic and particularly sustainable structures that should offer the construction sector completely new possibilities.

Forests are humanity’s treasure troves. And the best thing about them is that, if managed sustainably, they are eco-friendly and renewable. Every year, German forests grow around 122 million cubic meters of wood, while about 76 million cubic meters are harvested within the same period.

But there will be a huge increase in the demand for hardwood in the medium to long term. That’s why the TLH approach is to ensure that it is recycled. The more often it is recycled before it ends up as firewood or paper, the better. In the case of wood, this recycling process is referred to as ‘cascade use’. The goal is for the raw material to be recycled at least until a new tree has sequestered the quantity of CO₂ that will be emitted by the burning of the exhausted raw material. The large stock of hardwood in Germany provides the basis for a wood recycling system. Future-oriented hardwood products will enable us to reduce CO₂ emissions while at the same time sustainably promoting the economic diversity of domestic forests. It is also important to remember that the more demand for wood we meet from domestic sources, the less we have to import.