Staffan Berg

Greenhouse gas balance of harvesting stumps and logging residues for energy in Sweden

Abstract In this case study, forest fuel procurement chains of stumps and logging residues were evaluated using a Life Cycle Assessment perspective. Direct emissions from combustion were not included, but soil organic carbon change was included as changes in carbon stocks in litter and soil. The results showed that primary forest biomass for energy has a climate impact which is time dependent. However, in long-time perspectives, there are large greenhouse gas (GHG) savings. In a short-term (20 years), there were no GHG savings when natural gas or coal was replaced. This is due to the fact that the harvest lead to decreased input of organic matter to the soil which is compared to a reference where biomass are left to decompose. The reduction in soil organic carbon may have been underestimated in the stump harvest systems studied, as the effect of soil disturbance per se was not included. Important factors when assessing GHG balance of forest fuels, besides the time horizon used, were site productivity, geographical position and forest fuel resource (stumps or logging residues). When assessing the greenhouse gas savings, efficiency of the end-use, allocation method between heat and power and type of fossil fuel replaced were also important.

Some aspects of LCA in the analysis of forestry operations

Abstract This study demonstrates how the LCA technique can be used to address issues concerning environmental stress caused by forestry. The stress caused by the use of fossil fuels is analysed for different forestry operations. Comparisons are made between: • • clear cutting and shelterwood cutting in forest-management systems based on even-aged management; and • • mechanized and motormanual operations for felling and bucking. The analysis is based on data from northern and southern Sweden. Results show that motor-manual methods cause considerably lower emissions of CO 2 and NO x computed per cubic metre (solid o.b.) of harvested wood. The use of shelterwood systems gives rise to emissions about 10% (felling) and 20% (forwarding) higher than those from clear cutting. The results reflect the situation in Swedish forestry in the early 1990s. Since the use of the studied systems is influenced by the prevailing economic, climatic and biological conditions, the demonstrated effect is not caused by the difference in logging technique alone.

Energy requirement and environmental impact in timber transport

Transportation of timber from forests to industrial sites consumes more fossil fuels than any other part of the Swedish wood supply chain. This paper compares the environmental performance and energy requirements of a range of possible long-distance transport strategies involving lorry or lorry-and-train combinations using a variety of potential fuels/energy carriers, including diesel-oil, coal, hydropower, nuclear fuel and biofuels. The total efficiency of the complete system (i.e. “well-to-wheel” efficiency) is considered. The results indicate that transport alternatives including railway transport require less process energy than options relying exclusively on road vehicles. However, calculations showed that by using biofuels instead of fossil fuel in a lorry, it is possible to replace 96% of the fossil energy.

Evaluation of forest operations in Spanish eucalypt plantations under a life cycle assessment perspective

Abstract The forest is an essential natural resource providing multiple benefits to people. However, forests face several environmental problems created by modern industrial society such as acidification, eutrophication and global warming. This study investigated the environmental loads associated with the Spanish forest sector, where this activity plays an important role in socioeconomic development. A Eucalyptus globulus plantation located in north-western Spain was considered as a case study. Forest operations were divided into three subsystems: silvicultural operations, logging operations and secondary hauling. The results showed that logging operations consume more energy than any other part of the wood supply chain, with a remarkable contribution in the potential impact categories of global warming, acidification and photochemical oxidant formation. Transportation of timber from forest landing to industrial sites (secondary hauling) is the second most important energy user. Silvicultural operations made an important contribution to eutrophication, mainly due to phosphorus-based fertilizer application. This study will enable improved Iberian life cycle assessment studies of wood products in the absence of detailed studies for this region.

Indicator development in sustainability impact assessment: balancing theory and practice

In this article, the development and operationalisation of forestry-wood chain indicators within the frame of sustainability impact assessment are discussed. The analytical framework follows a distinction between indicator definition and selection in a first phase, and a second operational phase of indicator application in terms of interconnecting material flows, calculation of chain performance and utilisation within evaluation components. A clear boundary drawing effort in terms of the development of indicator definitions, related subclasses, and measurement units as well as the creation of conversion factors between indicator values and individual chain stages supports this. Economic, social and environmental indicators have to respond to data collection needs on individual process levels (that correspond to sub-divisions of the forestry-wood chain). For the usage of indicators within evaluation tools, a functional hierarchy has to be provided that supports clear preference elicitation as well as information on related externalities. In total, this paper aims at demonstrating an enhanced spectrum in the use of sustainability indicators, and the challenges that arise from a developing and applying multi-functional indicators in sustainability impact assessment.

Comparative environmental assessment of wood transport models: A case study of a Swedish pulp mill

Wood transportation from forest landing to forest-based industries uses large amounts of energy. In the case of Sweden, where forest operations are highly and efficiently mechanized, this stage consumes more fossil fuels than other elements of the wood supply chain (such as silviculture and logging operations). This paper intends to compare the environmental burdens associated to different wood transport models considering a Swedish pulp mill as a case study by using Life Cycle Assessment (LCA) as an analytical tool. Five scenarios (the current one and four alternative reliable scenarios) were proposed and analysed taking into account two variables. On the one hand, the influence of imported pulpwood share from Baltic countries and on the other hand, the use of rail transportation for wood transport. In particular, the following impact categories were assessed: Eutrophication, Global Warming, Photochemical Oxidant Formation, Acidification and Fossil fuel extraction. The environmental results indicate that transport alternatives including electric and diesel trains, as well as the reduction in Baltic wood imports should present better environmental performance than the current scenario in terms of all the impact categories under study. Remarkable differences were identified with regard to energy requirements. This divergence is related to different long-distance transport strategies (lorry, boat and/or train) as well as the relative import of wood selected. The combination of lorry and train in wood transportation from Southern Sweden plus the reduction of wood imports from 25% to 15% seems to be more favourable from an environmental perspective. The results obtained allow forecasting the importance of the wood transport strategy in the wood supply chain in LCA of forest products and the influence of energy requirements in the results.

Harvesting technology and market forces affecting the production of forest fuels from Swedish forestry

Abstract The Swedish forest industry sector produces timber, energy and other commodities, but has to consider the vested interests of other parties. This paper adopts a perspective whereby the modern forest industry sector is regarded as a system for the production of energy products, and where traditional forest industry products are seen as commodities that are released as energy at the end of their lives. Assisted by a review of the literature, the market forces affecting forest fuels are assessed from the perspectives of forest owners, machine contractors and purchasers of forest fuels. Present-day forest operations are highly efficient in terms of invested and inherent energy in harvested timber. There are also markets, methods and technology for the production of biofuels. However this harvest entails economic and environmental costs. The markets for biofuels seem to be growing, and bioenergy from forests competes with energy produced by other actors. Designing systems that provide a profitable flow of bioenergy from forestry without risking the sustainable use of forests as regards the long-term supply of nutrients and maintaining biological diversity constitutes a challenge for scientists and practitioners working in the sector. The author suggests existing systems for environmental and forest certification as a means of safeguarding and confirming that the harvest and trade of forest fuels comply with standards for ensuring sustainable forestry.

Towards assessing the sustainability of European logging operations

The forest-based sector has been at the forefront in operationally implementing the sustainability concept, its associated principles and indicators for sustainable forest management. Several methods have been developed to study environmental impacts of forestry activities, but none of the existing tools address all the dimensions of sustainability along the whole forest wood chain (FWC) in a balanced way. Consequently, the decision was made to develop a tool for sustainability impact assessment (ToSIA), the modelling framework for sustainability impact assessment of FWCs. The objective of the EU Project Eforwood was to develop ToSIA, a decision support tool. Within ToSIA, a FWC is modelled as a number of interconnected processes. For each process, a range of economic, environmental and social indicators and their respective values are calculated, thus representing the three pillars of sustainability. By this method, the multifunctionality of forests can be assessed and supply chains can be compared with respect to sustainability. Sensitivity analysis and scenario techniques can be applied to learn about the effect of expected changes to the structure of the chain, the material flows and the indicator values. In order to provide the tool with information about forest and logging operations, data were collected at two fundamental levels: (1) a regional level with case studies in Scandinavia, Iberia and Baden-Württemberg and (2) a European level with a case study that reflects conditions in the 27 countries of the European Union. This paper describes and details the harvesting and logging processes for the European countries. The results are displayed for each of the three regional case studies as well as aggregated to five principal areas in Europe: Eastern, Northern, Western, Central and Southwest Europe.

Energy Use in Swedish Forestry in 1972 and 1997

Abstract A comparison is made of energy usage and the contribution made to the global warming potential (GWP) by present (1997) and past (1972) forestry operations (including secondary haulage) in Sweden. The results are expressed in units of one cubic metre (solid u.b.) of harvested timber. The results indicate that, since 1972, improvements in fully mechanized forestry operations, particularly logging, have led to a reduction in total energy use from 1972 (236 MJ). In fact, the energy used by today’s (1997) mechanized logging systems (147–200 MJ) is roughly the same as that used by motormanual systems back in 1972 (156–177 MJ). The same is true as regards the contribution made to global warming potential: more fossil carbon was released in mechanized forestry (22 GWP) in 1972 than in 1997 (13–17 GWP). What’s more, the contribution to GWP in 1997 is on the same level as that made by motormanual systems in 1972 (15–16 GWP). It is accepted that forest management in Sweden mitigates the global warming potential. This is because the resulting sequestration effect in forest biomass is greater than the level of emissions from forestry operations.

Economic, environmental and social impact of alternative forest management in Baden-Württemberg (Germany) and Västerbotten (Sweden)

The forest sector is important for the German Federal State of Baden-Württemberg (BW) and the Västerbotten (VB) County in Sweden. Their forestry wood chains (FWCs) are of similar magnitude and supply forest industries. This study provides a regional comparison of the performance of FWCs from roundwood harvesting, including hauling, to mill gate concerning the factors that impact sustainability and assess different sustainability indicators for alternative supply chains, in particular fully mechanized chains in comparison to motor-manual operations. The harvest volumes are similar but operational conditions differ. Analysis of sustainability indicators demonstrated that the total costs for roundwood to industry are similar. Higher harvesting costs in BW are compensated for by lower transport costs to the mills. Employment per unit is higher in BW because of the high share of labour in felling. Due to smaller machinery and shorter transport distances in BW, energy use and greenhouse gas emissions per unit are lower than in VB. Areas for improvement are the technologies for logging in BW and the logistics of timber transport in VB.