Improved environmental assessment in the development of wood-based products: Capturing impacts of forestry and uncertainties of future product systems

Licentiate thesis, 2013

The prospect of reducing environmental impacts is a key driver for the development of new wood-based products. But as wood-based products are not necessarily environmentally superior to non-wood alternatives, there is a need to assess the environmental impact of the product and guide the development process. The aim of this research is to improve the methodology of such environmental assessments, to better capture the inherent uncertainties of future, still non-existent product systems and to improve the impact assessment of forestry. For capturing uncertainties, two approaches for scenario modelling were used in life cycle assessments (LCAs) of wood-based roof constructions and textile fibres. In the first approach, scenarios were set up to explore how different future technologies and methodological approaches (consequential and attributional) influence the assessment of life cycle processes occurring in a distant and uncertain future. In the second approach, scenarios with different geographical locations for the life cycle processes were generated by varying the future demand for textile fibres and the competition for forest land. Both approaches generated results which differed significantly between the scenarios; thus the approaches enabled a more comprehensive assessment than if only one scenario had been set up. The approaches can be recommended particularly for assessments of long-lived products and products with globally distributed supply chains. For improving the impact assessment of forestry, methods suggested in the literature were used and further developed in an LCA of wood-based textile fibres. The methods captured the land use impact on biodiversity and the water use impact on human health, ecosystem quality and resources. A new inventory approach was developed to better capture the system-scale effects that forestry can have on the hydrological cycle. Besides identifying opportunities for further methodological improvements, the methods generated meaningful results beyond what is offered by established methods for impact assessment. In particular, the consequential inventory approach made it possible to discern that land use can contribute positively to downstream water availability under certain conditions.