BFW - Forest management is crucial for the green house gas balance
The demand for wood is determined by political targets and economic market conditions.
How far this demand can be covered by the wood supply from Austrian forests and how the wood harvests affect the national GHG balance was the scientific objective of the study conducted at the BFW. Based on the data of the Austrian National Forest Inventory (ÖWI) the development and changes of the forests was predicted in model-runs for the different scenarios. The results provide the input for projecting the carbon stock changes of forest trees and in forest soils.
“Forest ecosystems could store more carbon than they do today under the current management practices”, explains Dr. Klemens Schadauer, Department of Forest Inventory. “In absence of harvesting activities the forests would reach a state of equilibrium that has 50% higher carbon stock than forests have today. This conclusion is focussed solely on forest ecosystems and, however, does not take into account the intrinsic positive impact of wood harvesting and wood utilization in HWPs on the GHG balance from a long-term perspective.
BOKU - The cascading utilisation of timber is more beneficial in the long run
Timber is the base material for many production processes and products from wood industries play an important role in the Austrian value-added chain, encompassing the wood and sawmilling industry, as well as the furniture and paper production. A key concept is the cascade utilization and the multiple usages of wood and wood products. It is based on the idea to achieve with the least possible input of wood amount the highest possible usage for material and energy purposes. A popular example is the reclamation of long-lasting wood products after their initial use by the paper industry, where repeated recycling is common practice.
“The examined scenarios show that the cascading utilization of wood is better for the Austrian GHG balance, compared to an instant utilization only for energy production. A high durability of wooden products can reinforce these effects”, says Dr. Peter Schwarzbauer, BOKU. He and his team investigated the carbon storage capabilities of harvested wood products.
Environmental Agency Austria - Wood products substituting fossil oil and energy-intensive resources
Replacing energy-intensive resources as for example steel or fossil oil by wood has a positive impact on the GHG balance. The objective of the investigations by the Umweltbundesamt was the substitution effects achievable through the use of wood products. Even though the annual harvest amount in Austria would equal the annual increment – in this case GHG emissions from Austrian forests would be zero - the use of wood and wood products would still have a relevant positive impact and reduce the GHG emissions.
“The overall effect of replacing energy-intensive resources by HWP over 90 years compares with the GHG emissions that will be produced within the next 20 years in Austria”, highlights Dr. Peter Weiss, Umweltbundesamt.
A moderate increase of growing stock volume in Austria - by about half of the magnitude of the last decades – has additional positive impacts on the GHG balance of the wood production chain. However, one requirement is that the sawn wood production will not be limited for the cascading utilization of wood and wood products. A reduced supply with sawn wood leads to an increasing use of energy-intensive resources and has negative impacts on the balance of GHGs.
Wood resources are not unlimited
An increasing demand for wood products can lead to wood harvests that exceed the annual growth in the forests. Over-utilization would have a negative impact on the GHG balance of the whole wood production chain, although it would lead to a decrease in the use of CO2-producing resources like fossil oil and steel. Therefore, the advantage of wood utilization on the GHG balance cannot be considered isolated without taking into account the effects of forest management. The sustainability of growing stock, the efficient management of forests and harvesting of the renewable but not unlimitedly available wood resources constitute the frame of additionally relevant factors.