MOBSTRAT: Timber mobilisation strategies for Swiss forests

Relying on three case studies, we created models to highlight the obstacles and the potential of increasing the use of wood. We also generated quantitative estimates of the long-term availability of wood.

By using more Swiss timber, we could contribute to reducing environmentally harmful greenhouse gases and implement the Swiss energy strategy. But the increased use of wood might be in conflict with other forest services such as leisure, wildlife and carbon storage. In addition, it might limit future generations in their options for using wood.

MOBSTRAT aimed to develop management strategies for increasing the use of wood and to explain their advantages and disadvantages and their application potential. Based on three case studies (Aargau, Grisons, Ticino) and data of the National Forest Inventory, the researchers used computer models to estimate the potentially usable amounts of wood for the next century as well as the associated harvesting costs. In their evaluation, they considered aspects such as wood increment, protection against natural hazards, carbon storage, suitability for recreation, biodiversity and regional economies. Stakeholders were involved in developing the strategies and a participatory approach was adopted for the case study in Ticino.

The MOBSTRAT project aimed to improve the methods for modelling and estimating wood resources. The researchers wanted to highlight the conditions under which wood use could be increased while maintaining sustainability. MOBSTRAT also contributed to the refinement of tools used by decision-makers in politics and the forestry sector. These tools give them a better understanding of the consequences of increased wood use and support them in making decisions and in acting on them.

The study showed that financial support for targeted protection forest management is a very important driver for timber harvesting. Furthermore, the researchers calculated that increased use of wood in the next few decades, i.e. a reduction of growing stocks, will lead to reduced increment afterwards. The long-term analysis of this study therefore suggests that periods of intensified use are balanced out by periods of reduced use.

The case study in the canton of Aargau shows among other things that the use of wood could be increased by 25% if more conifers were planted and the rotation age were reduced. But this strategy is risky because spruce, the main conifer occurring in the canton of Aargau, is sensitive to warmer climatic conditions. In addition, the costs for decortication and limbing of conifers are higher than for deciduous trees. If growing stocks were reduced without boosting conifers, yield could be improved by 9% but, as of 2050, this approach would negatively affect wood increment and availability to future generations. Further calculations showed that felling costs would be slightly higher and yields reduced if trees providing valuable habitats were preserved.

The case study in the canton of Grisons showed that protection forests play an important role in mobilising timber, since their management is financially supported by the federal government and the cantons. In Alpine forests, use could be increased by 50% or more without timber stocks declining. But this would go hand in hand with rising harvesting costs as felling would increasingly take place in poorly accessible forests.

For the case study in the canton of Ticino we worked with stakeholders and developed a suite of management scenarios for forests with chestnut dominance, an important tree species in the region. But these scenarios could only be implemented if generous subsidies and more forestry workers were to be made available. Corresponding efforts in professional training would also be essential. The three case studies show that in particular the increased use of protection forests would mobilise timber and at the same time improve the state of these forests. In other forests, the intensified use of wood is not economically feasible. Working with relevant stakeholders at an early stage facilitates the implementation of timber mobilisation.

MOBSTRAT: Timber mobilization strategies for Swiss forests: Assessing opportunities and constraints on different spatial and temporal scales