Tree stump harvesting and its environmental consequences
The stumps left in Swedish forests after felling are a resource that has hitherto been scarcely used to produce bio fuels, even though these stumps represent more than 20 per cent of the biomass of coniferous trees. At present it is difficult to say whether it is environmentally acceptable to harvest tree stumps on a large scale, since there are large gaps in our knowledge at all stages – from the logistics of grubbing up stumps to impacts on rivers and streams, biodiversity, forest production and carbon and nitrogen cycles. For this reason the Faculty of Natural Resources and Agricultural Sciences at SLU and the Swedish Energy Agency, with contributions from the forest industry, have now initiated a major research programme on positive and negative impacts of stump harvesting. The research is intended to result in new recommendations on the types of stumps and habitats that should be excluded in the interests of sustainable stump harvesting, and how ground disturbance can best be avoided.
An international symposium "Tree-stumps for bioenergy - harvesting techniques and environmental consequences" will be held on October 24-26, 2011 at the Swedish University of Agricultural Sciences in Uppsala, Sweden. Read more ...
Research areas
The research programme involves around 20 researchers from the faculty, but several projects are carried out in close cooperation with researchers at Skogforsk (the Forestry Research Institute of Sweden), Metla in Finland and IVL Swedish Environmental Research Institute. Programme coordinator and chairman of the steering committee is Professor Tryggve Persson at the Department of Ecology. The programme focuses on four major areas:
The objective of the project Tree stump fuel quality and environmental effects from a systems perspective is to identify systems that have minimal environmental effects in relation to the amount of energy produced. Among the questions that are adressed are the effects of storing and handling of stump substrate on fuel quality, and ways to achieve a favourable energy balance.
Contact person: Raida Jirjis
The project Effects on forest pests and pathogens concerns the minimum amount of stumps that need to be removed if damage by pine weevils and root rot is to be reduced. Here we study the effects of stump harvesting on the survival of tree plants and on timber quality, and hence on forest economy.
Contact person: Helena Bylund
Effects on biodiversity is a project that looks at the amount of stumps that can be removed without seriously harming biodiversity. The fauna and flora on stumps are examined in relation to what is found on other substrates. Vital aims are to identify stump qualities and forest types that need to be excluded from harvest. At the same time we need to identify areas that are suitable for large-scale stump harvesting, with consideration taken to which measures strengthen biodiversity at a landscape level.
Contact person: Håkan Berglund
In the Carbon and nutrient cycles and water quality project we address the effects of stump harvesting on carbon and nutrient balances and on flows of particles, mercury and soluble organic carbon to lakes and watercourses.
Contact person: Riitta Hyvönen-Olsson
Responsible for this page: David Stephansson