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The potential use of residues from the logging process was evaluated for electrical energy generation by direct combustion. The findings were based on logging residues accrued from 1990 to 2015 and were enumerated using a 43% residue recovery rate. The available logging residues were insufficient to supply the primary electrical energy demand as well as reduce the emission of carbon dioxide. However, when coupled with other agricultural residues, the potential energy generation from biomass was significant and could not only lead to reduced fossil fuel demand, but also improve the carbon credit and provide additional employment opportunities in the bioenergy sector. [ABSTRACT FROM AUTHOR]

Biomass is the renewable resource with the potential to serve as a substitute for fossil fuels. A form of biomass, woody residues, includes woody byproducts such as mill residues, logging residues, and other wood waste. This study estimated the impact of woody residue processing capacity, mill willingness to utilize additional logging residues for electricity production, mill equipment upgrades to facilitate electricity production, and different factors limiting the utilization of logging residues on the utilization of woody residues by mills. Data on the utilization of woody residues were collected via a census mail survey of mills in the southern United States. Data were analyzed using a two-stage least square (2SLS) regression model. Results indicated that average utilization was 91% of available woody residue processing capacity for bioenergy. Woody residue utilization increased with an increase in the processing capacity of woody residues, equipment upgrades, and lower transportation costs. In addition, the study found that there were only a few mills with a large enough processing capacity to utilize woody residues for bioenergy production. Thus, an increased utilization of woody residues will be highly dependent on mills' ability to increase woody residues processing capacity, implement necessary equipment upgrades, and lower transportation and processing costs. Logging residue utilization was relatively limited and had less of an impact on overall woody residue utilization. Findings will assist policy makers and mill managers in making informed decisions about woody residue utilization and identify specific mill factors that might help improve the economic feasibility of using woody biomass for bioenergy purposes. [ABSTRACT FROM AUTHOR]

Accurately assessing the delay before the substitution of fossil fuel by forest bioenergy starts having a net beneficial impact on atmospheric CO2 is becoming important as the cost of delaying GHG emission reductions is increasingly being recognized. We documented the time to carbon ( C) parity of forest bioenergy sourced from different feedstocks (harvest residues, salvaged trees, and green trees), typical of forest biomass production in Canada, used to replace three fossil fuel types (coal, oil, and natural gas) in heating or power generation. The time to C parity is defined as the time needed for the newly established bioenergy system to reach the cumulative C emissions of a fossil fuel, counterfactual system. Furthermore, we estimated an uncertainty period derived from the difference in C parity time between predefined best- and worst-case scenarios, in which parameter values related to the supply chain and forest dynamics varied. The results indicate short-to-long ranking of C parity times for residues < salvaged trees < green trees and for substituting the less energy-dense fossil fuels (coal < oil < natural gas). A sensitivity analysis indicated that silviculture and enhanced conversion efficiency, when occurring only in the bioenergy system, help reduce time to C parity. The uncertainty around the estimate of C parity time is generally small and inconsequential in the case of harvest residues but is generally large for the other feedstocks, indicating that meeting specific C parity time using feedstock other than residues is possible, but would require very specific conditions. Overall, the use of single parity time values to evaluate the performance of a particular feedstock in mitigating GHG emissions should be questioned given the importance of uncertainty as an inherent component of any bioenergy project. [ABSTRACT FROM AUTHOR]

The article deals with the evaluation of the hypothesis that long-term sustainable potential of solid biomass (the so-called standard potential) for energy purposes can be significantly increased in the short run when breaking some constraints assumed for biomass growing, collection and utilization. Evaluation of biomass potential (both standard and additional) is based on a developed methodology using detailed spatial and empirical data (GIS). Potential is determined for the defined area using a bottom-up approach where these yields are derived in relation to climate and soil conditions of each land plot of agricultural and forest land. Results of methodology testing have proven that biomass potential from agriculture and forest land can be significantly increased in the short run (typically from 18% up to 40% in our case studies depending on biomass source and region). There are three major sources of additional biomass potential: reduction of straw ploughed into soil, changes in utilization of harvested timber from forests and shortening of rotation of SRC plantations. Performed analyses show great variations of biomass potential between the regions depending mainly on composition and age distribution of the forests stands in studied regions of similar size. [ABSTRACT FROM AUTHOR]

Increased use of forest biomass for energy and rising transportation costs are forcing biomass suppliers towards better moisture content management in the supply chain. Natural drying is used to decrease moisture content of energy wood. Drying is dependent on wood characteristics and weather conditions. Weather-dependent drying models for estimating the optimal storage time based on average moisture changes in fuel wood stacks stored outdoors have been developed for different stem wood and logging residues. Models are an easy option for estimating the moisture content of energy wood piles compared to sampling and measuring the moisture of samples. In this study, stand and roadside storage models for logging residues were validated against data from field studies and forest companies. Over 200 reference piles for the stand model, 23 piles for the roadside model and 10 piles for the combined model were studied. Results of the validation are promising. The difference between measured and modelled moisture was on average only 0.35%. The presented models can be implemented anywhere in Finland, because the Finnish Meteorological Institute has a weather observation service offering weather history data for every location in Finland. For international use, parameters need to be estimated on a case by case basis, but it should be possible to implement the approach also elsewhere. [ABSTRACT FROM AUTHOR]

The European Union relies largely on bioenergy to achieve its climate and energy targets for 2020 and beyond. We assess, using Attributional Life Cycle Assessment (A-LCA), the climate change mitigation potential of three bioenergy power plants fuelled by residual biomass compared to a fossil system based on the European power generation mix. We study forest residues, cereal straws and cattle slurry. Our A-LCA methodology includes: i) supply chains and biogenic-CO 2 flows; ii) explicit treatment of time of emissions; iii) instantaneous and time-integrated climate metrics. Power generation from cereal straws and cattle slurry can provide significant global warming mitigation by 2100 compared to current European electricity mix in all of the conditions considered. The mitigation potential of forest residues depends on the decay rate considered. Power generation from forest logging residues is an effective mitigation solution compared to the current EU mix only in conditions of decay rates above 5.2% a −1 . Even with faster-decomposing feedstocks, bioenergy temporarily causes a STR(i) and STR(c) higher than the fossil system. The mitigation potential of bioenergy technologies is overestimated when biogenic-CO 2 flows are excluded. Results based solely on supply-chain emissions can only be interpreted as an estimation of the long-term (>100 years) mitigation potential of bioenergy systems interrupted at the end of the lifetime of the plant and whose carbon stock is allowed to accumulate back. Strategies for bioenergy deployment should take into account possible increases in global warming rate and possible temporary increases in temperature anomaly as well as of cumulative radiative forcing. [ABSTRACT FROM AUTHOR]

Harvesting stumps and logging residues for energy production may have negative impacts on forest species, especially those associated with dead wood. We assessed the potential impact of biofuel harvest on epiphytic lichens by studying the lichen assemblages on stumps and downed fine woody debris (FWD) of Scots pine ( Pinus sylvestris L.) in clear-cut, mature managed, and old-growth forest stands in eastern Finland. We also examined the impact of tree retention level and prescribed burning on these assemblages. A total of 102 lichen species (including 13 red-listed species) were observed, with 95 species on stumps and 69 species on downed FWD. Composition of the species assemblages differed between stumps and downed FWD and between stumps of different age. Tree retention (in comparison with clear-cut sites) and prescribed burning resulted in a slightly higher species richness on cut stumps 12 years after harvest but did not affect the assemblages on downed FWD or older stumps. We conclude that stumps and downed FWD of Scots pine can host high numbers of lichen species, including red-listed ones. Most of the species occurred also on other substrates and are, therefore, not likely to be affected by biofuel harvest. However, for dead wood dependent lichen species, intensive biofuel harvest is potentially harmful, though the severity of this impact likely depends on the landscape-level availability of other woody substrates. [ABSTRACT FROM AUTHOR]

The European Union (EU) relies largely on bioenergy to achieve its climate and energy targets for 2020 and beyond. Special focus is placed on utilization of biomass residues, which are considered to cause low environmental impacts. We used the dataset from the latest European Commission document on the sustainability of solid and gaseous biomass (SWD2014 259), complementing those results by: i) designing three pathways for domestic-heat production using forest logging residues, with different combustion technologies; ii) expanding the analysis to include forest carbon stock development with and without bioenergy; iii) using absolute climate metrics to assess the surface temperature response by the end of the century to a bioenergy and a reference fossil system; iv) including multiple climate forcers (well-mixed GHG, near term climate forcers and surface albedo change); iv) quantifying life cycle impacts on acidification, particulate matter emissions and photochemical ozone formation; v) reviewing potential risks for forest ecosystem degradation due to increased removal of residues. Supply-chain GHG savings of the three pathways analysed ranged between 80% and 96% compared to a natural gas system, above the 70% threshold suggested by the EU. However, the climate impact of bioenergy should be assessed by considering also the non-bioenergy uses of the biomass and by including all climate forcers. We calculate the Surface Temperature Response to bioenergy and fossil systems by means of Absolute Global surface Temperature Potential (AGTP) metric. Domestic heating from logging residues is generally beneficial to mitigate the surface temperature increase by 2100 compared to the use of natural gas and other fossil sources. As long as residues with a decay rate in the forest higher than 2.7%*yr −1 are considered as feedstock, investing now in the mobilization of residues for heat production can reduce the temperature increase by 2100 compared to all the fossil sources analysed, both in case of bioenergy as a systemic change or in case of bioenergy as a transitory option. Furthermore, several environmental risks are associated with the removal and use of forest logging residues for bioenergy. These issues concern mostly local air pollution, biodiversity loss and, mainly for stumps removal, physical damage to forest soils. Forest logging residues are not free of environmental risks. Actions promoting their use should consider: (i) that climate change mitigation depends mainly on the decay rate of biomass under natural decomposition and time and rate of technology deployment, (ii) whether management guidelines aimed at protecting long-term forest productivity are in place and (iii) whether proper actions for the management of adverse effects on local air pollution are in place. [ABSTRACT FROM AUTHOR]

Increasing bioenergy production from forest harvest residues decreases litter input to the soil and can thus reduce the carbon stock and sink of forests. This effect may negate greenhouse gas savings obtained by using bioenergy. We used a spatially explicit modelling framework to assess the reduction in the forest litter and soil carbon stocks across Europe, assuming that a sustainable potential of bioenergy from forest harvest residues is taken into use. The forest harvest residue removal reduced the carbon stocks of litter and soil on average by 3% over the period from 2016 to 2100. The reduction was small compared to the size of the carbon stocks but significant in comparison to the amount of energy produced from the residues. As a result of these land-use-related emissions, bioenergy production from forest harvest residues would need to be continued for 60-80 years to achieve a 60% carbon dioxide ( CO2) emission reduction in heat and power generation compared to the fossil fuels it replaces in most European countries. The emission reductions achieved and their timings varied among countries because of differences in the litter and soil carbon loss. Our results show that extending the current sustainability requirements for bioliquids and biofuels to solid bioenergy does not guarantee efficient reductions in greenhouse gas emissions in the short-term. In the longer-term, bioenergy from forest harvest residues may pave the way to low-emission energy systems. [ABSTRACT FROM AUTHOR]

Whole-tree harvesting is an increasingly common harvesting method due to the high demand for fuel chips. In whole-tree harvesting, nutrient removal from the site is substantially higher than in cut-to-length harvesting, in which nutrient-rich branches and unmerchantable top sections of trees are left in the cutting area. There is a concern that whole-tree harvesting impairs site productivity, especially on mires drained for forestry. We employed six field experiments to study the effects of the harvesting method used on the amount of logging residues left on the site in the thinning of Scots pine (Pinus sylvestris L.) stands. The four harvesting treatments varied in their intensity of biomass removal from conventional stem-only harvesting (CTL), where tree tops and branches were left on the site to whole-tree harvesting (WTH) complemented by the manual collection of residues. Logging residues left on the sites were weighed and sampled to determine their moisture content. After CTL, the amount of logging residues left on the site was 7780-15340 kg ha-1(dry mass), depending on the experiment. In (WTH) the amount of logging residues left on the site was 32-66% of that of CTL. After the manual collection of residues in WTH, 4-16% of the residues still remained on the sites. The residues left at site following WTH had a larger share of small-diameter material than after CTL. [ABSTRACT FROM AUTHOR]

Abstract: In this study, life cycle assessment (LCA) is used to assess and compare the environmental and energy profiles of three potential bioenergy production chains using different available feedstocks in Southern European countries. Two wastes, vineyard pruning and eucalypt logging residues, and a wooden energy crop, poplar, were examined in detail. The comparative LCA study showed that the use of poplar biomass for bioenergy production has a greater impact than the use of vineyard pruning and logging residues. The contribution from the poplar-cultivation-related activities considerably affected the results, as all the activities from field preparation to harvesting have been included within the system boundaries. In contrast, all the activities performed in the vineyard and forest prior to collection of the residues have not been computed in both scenarios since they have been allocated to the driving force of these stands: grapes and roundwood, respectively. The results support the idea that forest and agricultural waste would be an interesting and potential raw material for bioenergy purposes. However, further analysis should focus on these potential bioenergy sources, namely in terms of their availability and technical burning conditions, in order to meet energy requirements. Moreover, the environmental results were compared with others from literature corresponding to electricity production using alternative biomass sources and fossil fuels. In all the categories considered for comparison, environmental benefits were reported for the electricity production using a biomass source. However, these results must be carefully used since other issues – such as production costs, water availability and land use – should be considered. [Copyright &y& Elsevier]

The review gives an overview of the increased utilization of forest biomass for energy. The emphasis is on Nordic countries, especially on Sweden and Finland with large biomass potentials and a high share of renewable energy in gross final energy consumption. The utilization and potential of forest chip sources such as logging residues, small-size tree stems and stumps that are normally not harvested in conventional harvesting are described. Environmental potential and impacts that may reduce the utilization of forest biomass are discussed based on recent publications. Finally, the review summarizes the future developments based on their relationship to policies, certifications and guidelines and forest owners' decisions. [ABSTRACT FROM AUTHOR]

Purpose: Forest residues are becoming an increasingly important bioenergy feedstock. This study evaluates the environmental impacts associated with the production of fuel chips from eucalypt logging residues in Portugal, in order to identify the supply chains and machinery that bring the best environmental performance. Besides, the stages and operations with the largest environmental impact are identified. Methods: Life cycle assessment methodology is used starting with forest management up to delivery of chips to power plant. Three different configurations for logging residue processing were simulated as follows: roadside chipping of loose residues, terminal chipping of loose residues, and terminal chipping of bundled residues. In addition, the use of different equipment for tree felling and extraction of logging residue was considered. The default impact assessment methodology was the CML. In a sensitivity analysis, calculations were performed using characterization factors recommended by the International Reference Life Cycle Data System (ILCD). Different allocation criteria were tested for partitioning the environmental burdens between wood and forest residues produced during the stage of forest management. Results and discussion: Roadside chipping of loose residues seems to have less impacts regardless of the equipment used in tree felling and residue forwarding. However, for photochemical oxidant formation, this is not the case when trees are felled with a chainsaw when the CML methodology is applied. For the systems with terminal chipping, the better option will depend both on type of machinery used and distances traveled between the forest site and the power plant. The forest management stage has a relevant contribution to all the supply chains analyzed. Chipping and bundling have also important impacts, as well as forwarding when this operation is accomplished with a modified farm tractor. Moreover, transports have a significant impact when loose residues are chipped in a terminal. Conclusions: The choice of the allocation method between wood and residues affects significantly the absolute results, but it is irrelevant when the objective is to select the best supply chain configuration. The results obtained are valid for the input data considered, which rely on average values representative of the current most typical practices in Portugal. However, this methodology can also be applied as a decision supporting tool to select the supply chain with the best environmental performance on a case by case basis, using site-specific data. [ABSTRACT FROM AUTHOR]

Abstract: Forest logging residues are systematically left after exploitation. In Romania, logging residues were traditionally used by population for fuel but have not been considered at large scale for industrialization. The estimation of the resource needed a more accurate assessment and the development of devoted biomass models for large-scale applications. Our study aims at estimating the amount of logging residues based on direct biomass measurements for the two main species of Romanian Carpathian forests: Norway spruce and beech. A country-scale field measurement campaign resulted in the sampling of 100 Norway spruce and 74 beech trees. Models of logging residues biomass were developed for both species. The amount of potential logging residues per tree was greater in beech than in Norway spruce. The models developed, nonlinear by essence, showed that diameter-based equations enable the evaluation of individual logging residues potential. Using tree height as an additional independent variable did not improve the models. The models fitted were applied to yield tables in order to estimate the resource potential in spruce and beech stands for each productivity class, and its dynamic during the production cycle. The calculations proved that the potential amount of logging residue is larger in spruce stands. The amount in beech is very sensitive to the productivity class, unlike in spruce stands. The potential biomass produced during early thinnings is however greater in beech stands than in spruce ones. A more systematic and organized collecting of residues could offer a fast answer to the need of increasing renewable energy share. [Copyright &y& Elsevier]

Abstract: Forest treatments have the potential to produce significant quantities of forest residue biomass, which includes the tops and limbs from merchantable trees and smaller trees removed to meet management objectives. We spatially analyzed the sensitivity of financially feasible biomass volumes for delivery to a bioenergy facility across 16 combinations of delivered biomass and diesel prices for a 515,900 ha area in western Montana. At the lowest delivered biomass price analyzed, $31.52 per oven dried tonne (ODT), 28% of the potential volume was financially feasible at the lowest diesel price, $0.053 L−1, dropping off to 6% of the volume at the highest diesel price analyzed, $1.32 L−1. With a 50% increase in delivered biomass price to $47.28 ODT−1, feasibility increased to 88% at the $0.53 L−1 diesel price, dropping to 36% of the volume at the $1.32 L−1 diesel price. Another 50% increase in delivered biomass price to $63.05 ODT−1 resulted in the feasible volume converging on the total potential volume at the lower diesel prices, and at the highest delivered price, $78.81 ODT−1, nearly all potentially available biomass is financially feasible even at the highest diesel fuel price analyzed. Haul was almost entirely restricted to paved roads closest to the bioenergy facility at the lowest delivered biomass price. As delivered price increased, feasible volume expanded further into areas accessed by unpaved roads as well as paved roads further from the bioenergy facility. Results show that financial feasibility is much more sensitive to changes in delivered biomass prices than diesel prices. [Copyright &y& Elsevier]

Abstract: Converting fossil-based energy systems into carbon–neutral systems is an essential strategy to the reach targets set by the Kyoto Protocol. For nations with an active logging industry, salvaging logging residues or slash to produce bioenergy has a huge potential for development. However, removing forest woodfuel may have ecological consequences, notably for saproxylic biodiversity. The consequences of such removals on biotic assemblages in temperate forests remain poorly documented in comparison with boreal forests. In this study, we compared the species richness and composition of saproxylic beetle assemblages among different types of logging residues in several temperate oak-dominated French forests. We showed that residue tree species was the most important factor for saproxylic biodiversity, as it not only influences assemblage composition, but also species number. Oak and hornbeam logging residues were richer than logging residues from beech and spruce. Decay stage also appeared to be an important factor for saproxylic beetles associated to logging residues; richness was lower in fresh than in decayed residues. Moreover canopy closure had a strong and significant effect on beetle assemblages in logging residues. Lastly, residue diameter only partially explained differences in saproxylic beetles assemblages. Comparably to studies in boreal forests (mainly in Scandinavia), our results discuss the role of logging residues retention in maintaining saproxylic biodiversity in temperate forests. It may prove necessary not only to maintain adequate volumes of both fine and mid-size woody debris from varied tree species, but also to let some debris naturally and completely decay. [Copyright &y& Elsevier]

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. [ABSTRACT FROM AUTHOR]

Abstract: Energy wood harvesting in young forests presents an economical challenge and has been dependent on subsidies in Finland. Whole-tree harvesting systems have proved to be most productive when carrying out energy wood harvesting in cleanings and early thinnings in young forests. The application of integrated energy wood and pulpwood harvesting is less common. It was hypothesized that multi-tree harvesting (MTH) with the OM-Waratah 745 single grip harvester head could change harvesting logistics and improve productivity for integrated energy wood and pulpwood thinnings. Two variations of MTH were compared with single-tree harvesting (STH). The logging methods studied were: (1) conventional single-tree harvesting with pulpwood and energy wood processed at the strip road; (2) multi-tree harvesting with pulpwood and energy wood processing along the strip road (MTH1); and (3) multi-tree harvesting at the stump where the aim was to leave the logging residues distributed evenly over the harvesting area and not on the strip roads (MTH2). MTH methods were 28–35% more productive than the single-tree harvesting. The biggest differences in work stages were found in the felling and delimbing stages. In single-tree harvesting felling was 9–26% and delimbing 14–27% slower than in multi-tree harvesting. MTH2 distributed 13% of residues further than 7 m from the strip road center. With STH and MTH1 only a good 1.2–1.7% was placed this far, and 74.4 and 62.0% respectively within 3 m. [Copyright &y& Elsevier]

Abstract: The aim of this study was to determine the effect of whole-tree harvesting (WTH) on the growth of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) as compared to conventional stem harvesting (CH) over 10 and 20years. Compensatory (WTH+CoF) and normal nitrogen-based (CH+F or WTH+F) fertilisation were also studied. A series of 22 field experiments were established during 1977–1987, representing a range of site types and climatic conditions in Finland, Norway and Sweden. The treatments were performed at the time of establishment and were repeated after 10–13years at 11 experimental sites. Seven experiments were followed for 25years. Volume increment was on average significantly lower after WTH than after CH in both 10-year periods in the spruce stands. In the pine stands thinned only once, the WTH induced growth reduction was significant during the second 10-year period, indicating a long-term response. Volume increment of pine stands was 4 and 8% and that of spruce stands 5 and 13% lower on the WTH plots than on CH during the first and the second 10-year period, respectively. For the second 10-year period the relative volume increment of the whole-tree harvested plots tended to be negatively correlated with the amount of logging residue. Accordingly, the relative volume increment decreased more, the more logging residue was harvested, stressing the importance of developing methods for leaving the nutrient-rich needles on site. If nutrient (N, P, K) losses with the removed logging residues were compensated with fertiliser (WTH+CoF), the volume increment was equal to that in the CH plots. Nitrogen (150–180kgha−1) or N+P fertilisation increased tree growth in all experiments except in one very productive spruce stand. Pine stands fertilised only once had a normal positive growth response during the first 10-year period, on average 13m3 ha−1, followed by a negative response of 5m3 ha−1 during the second 10-year period. The fertilisation effect of WTH+F and WTH+CoF on basal area increment was both smaller and shorter than with CH+F. [Copyright &y& Elsevier]

Abstract: There are many possible systems for recovering, refining, and transporting logging residues for use as fuel. Here we analyse costs, primary energy and CO2 benefits of various systems for using logging residues locally, nationally or internationally. The recovery systems we consider are a bundle system and a traditional chip system in a Nordic context. We also consider various transport modes and distances, refining the residues into pellets, and replacing different fossil fuels. Compressing of bundles entails costs, but the cost of chipping is greatly reduced if chipping is done on a large scale, providing an overall cost-effective system. The bundle system entails greater primary energy use, but its lower dry-matter losses mean that more biomass per hectare can be extracted from the harvest site. Thus, the potential replacement of fossil fuels per hectare of harvest area is greater with the bundle system than with the chip system. The fuel-cycle reduction of CO2 emissions per harvest area when logging residues replace fossil fuels depends more on the type of fossil fuel replaced, the logging residues recovery system used and the refining of the residues, than on whether the residues are transported to local, national or international end-users. The mode and distance of the transport system has a minor impact on the CO2 emission balance. [ABSTRACT FROM AUTHOR]

Abstract: Following the European Union strategy concerning renewable energy (RE), Portugal established in their national policy programmes that the production of electrical energy from RE should reach 45% of the total supply by 2010. Since Portugal has large forest biomass resources, a significant part of this energy will be obtained from this source. In addition to the two existing electric power plants, with 22MW of power capacity, 13 new power plants having a total of 86.4MW capacity are in construction. Together these could generate a combination of electrical and thermal energy, known as combined heat and power (CHP) production. As these power plants will significantly increase the exploitation of forests resources, this article evaluates the potential quantities of available forest biomass residue for that purpose. In addition to examining the feasibility of producing both types of energy, we also examine the potential for producing only electric energy. Results show that if only electricity is generated some regions will need to have alternative fuel sources to fulfil the demand. However, if cogeneration is implemented the wood fuel resource will be sufficient to fulfill the required capacity demand. [Copyright &y& Elsevier]

Abstract: Mill residues from forest industries are the source for most of the current wood-based energy in the US, approximately 2.1% of the nation''s energy use in 2007. Forest residues from silvicultural treatments, which include limbs, tops, and small non-commercial trees removed for various forest management objectives, represent an additional source of woody biomass for energy. We spatially analyzed collecting, grinding, and hauling forest residue biomass on a 515,900ha area in western Montana, US, to compare the total emissions of burning forest residues in a boiler for thermal energy with the alternatives of onsite disposal by pile-burning and using either natural gas or #2 distillate oil to produce the equivalent amount of useable energy. When compared to the pile-burn/fossil fuel alternatives, carbon dioxide emissions from the bioenergy alternative were approximately 60%, methane emissions were approximately 3%, and particulate emissions less than 10μm were 11% and 41%, respectively, for emission control and no-control boilers. Emissions from diesel consumption for collecting, grinding, and hauling biomass represented less than 5% of the total bioenergy emissions at an average haul distance of 136km. Across the study area, an average 21 units of bioenergy were produced for each unit of diesel energy used to collect, grind, and haul biomass. Fossil fuel energy saved by the bioenergy alternative relative to the pile-burn/fossil fuel alternatives averaged 14.7–15.2GJt−1 of biomass. [Copyright &y& Elsevier]

Abstract: Here we examine the cost, primary energy use, and net carbon emissions associated with removal and use of forest residues for energy, considering different recovery systems, terrain, forwarding distance and forest productivity. We show the potential recovery of forest fuel for Sweden, its costs and net carbon emissions from primary energy use and avoided fossil carbon emissions. The potential annual net recovery of forest fuel is about 66 TWh, which would cost one billion €2005 to recover and would reduce fossil emissions by 6.9 Mt carbon if coal were replaced. Of the forest fuel, 56% is situated in normal terrain with productivity of >30 t dry-matter ha−1 and of this, 65% has a forwarding distance of <400 m. In normal terrain with >30 t dry-matter ha−1 the cost increase for the recovery of forest fuel, excluding stumps, is around 4–6% and 8–11% for medium and longer forwarding distances, respectively. The stump and small roundwood systems are less cost-effective at lower forest fuel intensity per area. For systems where loose material is forwarded, less dry-matter per hectare increases costs by 6–7%, while a difficult terrain increases costs by 3–4%. Still, these systems are quite cost-effective. The cost of spreading ash is around 40 €2005 ha−1, while primary energy use for spreading ash in areas where logging residues, stumps, and small roundwood are recovered is about 0.025% of the recovered bioenergy. [Copyright &y& Elsevier]

This analysis explores regional aggregate bioenergy potential, the interaction of logging residues and roundwood supply, and the potential supply costs of woody biomass from three southern states. Significant amounts of forest residues are potentially available within the study area: approximately 2.8 million dry tons in North Carolina, 1.8 million dry toffs in South Carolina, and 1.3 million dry tons in Virginia. These quantities are sufficient to satisfy regional biomass electricity production requirements only through 2012 under a hypothetical national Renewable Portfolio Standard and Renewable Fuels Standard, after which changes in the biomass resource stream will be necessary. Supply curves generated for multiple regions in each state indicate that forest residues vary regionally in both supply and price, and exceeding the supply of forest residues could be accompanied by a dramatic spike in resource pricing, with implications for timberland owners and users of the forest resource base. [ABSTRACT FROM AUTHOR]

Biodiversity management in broadleaved forests includes partial cutting to improve conditions for species that benefit from semi-open stand structure. The harvested wood is usually used as fuel and, therefore, it is stockpiled in situ for months before further processing. If such forest fuel piles attract saproxylic insects, they are likely to be ecological traps, because the settling cost for insects is death as the wood is chipped and used for energy. This study investigated beetle species composition in piles of oak wood in southern Sweden. Species density and frequency of occurrence were compared in wood with different diameters and at the top, middle and bottom parts of piles. A total of 39 species (six red-listed) and 3528 individual beetles emerged. The highest density of both individuals and species was in the top layer. No species was significantly more frequent in the middle or bottom layers. Diameter had only a limited effect on species density and individual species reproduced in both coarse and fine wood. In conclusion, forest fuel piles can be ecological traps for several uncommon and red-listed saproxylic beetles. The negative effects can be mitigated by removing the piles before the insects colonize them. If this is not possible, then the top layer should be retained. [ABSTRACT FROM AUTHOR]

The increasing demand for biofuel may decrease the dead wood supply in managed forests, and hence the amount of substrate available for dead wood dependent species. Slash is already being harvested for biofuel purposes, and stumps are an even bigger potential source of wood fuel. Both substrates constitute a major component of dead wood in managed forests, but have been poorly studied in terms of lichen diversity. We compared lichen species diversity between the lateral surface of slash and the cut surface of stumps of Norway spruce in planted boreonemoral Swedish forests of four age classes; 4–5, 8–9, 12–13, and 16–18 years. We also estimated the amounts of the two substrates, and discriminated between slash with bark and decorticated slash. There were no differences in species number per surface area, but slash had more species when equal volumes were compared. We found compositional differences between slash and stumps throughout the decay process. The majority of species found on both substrates were more frequent on stumps, which also had a higher number of unique species and species in the literature indicated as nationally rare or uncommon. The volume per hectare of stumps was ten times greater than that of slash but conversely, the lateral surface area of slash was five times greater than the cut surface area of stumps. Few dead wood specialist lichen species were, however, strictly associated with slash, whereas stumps offer a more heterogeneous environment and may provide important habitats for rare lichens in the managed forest landscape. [Copyright &y& Elsevier]

Knowledge of the canopy lichen flora of managed forests is poor, but needs more focus since, for example, slash (tops, branches and twigs) harvest for biofuel may pose a threat to epiphytic lichen diversity. This study compared lichen species richness, density and composition between stems, tops, branches and twigs of mature Norway spruce (Picea abies) and aspen (Populus tremula) in managed boreonemoral forests in south-central Sweden. The stems were also compared with the slash fractions pooled together. All comparisons were made separately for each tree species. In total, 30 lichen species were found on Norway spruce and 46 on aspen. No significant differences in species richness or species density between fractions were found for Norway spruce, whereas aspen tops were significantly less species rich and species dense than the other fractions. Moreover, aspen slash was significantly more species dense than the stem. The lichen species composition of the stems clearly differed from that of the tops, branches and twigs in both tree species. Thus, lichen communities other than those removed with stems by conventional forestry are removed from the stands owing to slash harvest. However, these species are rather common and widespread in Sweden. The impact of slash harvest on the epiphytic lichen flora may therefore be of minor importance in forests established after clear-cutting or on former arable land. [ABSTRACT FROM AUTHOR]

Abstract: Finland has large forest fuel resources. However, the use of forest fuels for energy production has been low, except for small-scale use in heating. According to national action plans and programs related to promotion of biofuels, the utilization of such resources will be multiplied over the next few years. The most significant part of this growth will be based on the utilization of forest fuels, produced from logging residues of regeneration fellings, in industrial and municipal power and heating plants. Availability of logging residues was analyzed by means of resource and demand approach in order to identify the most suitable regions with focus on increasing the forest fuel usage. The analysis included availability comparisons between power plant sites and resource allocation in a least-cost manner according to supply cost, and between a predefined power plant structure under given demand and supply constraints. Spatial analysis of worksite factors and regional geographies was carried out using the Graphics Information System-model (GIS-model) environment via geoprocessing and cartographic modeling tools. According to the site-specific analysis, the supply potential of different locations can differ multifold. However, due to technical and economical reasons of the fuel supply and dense power plant infrastructure, the supply potential is limited to plant level. Therefore, the potential and supply–cost calculations depend on site-specific matters, where regional characteristics of resources and infrastructure should be taken into consideration, e.g., by using a GIS-modeling approach constructed in this study. [Copyright &y& Elsevier]

Bioenergy has an important role in the implementation of the Kyoto agreement in Finland. The main sources of wood residues for energy production are logging areas and sawmills. The use of forest chips can be of great significance in reducing carbon dioxide emissions by replacing fossil fuels. Increasing the use of forest chips has environmental benefits, but it also includes possible environmental disadvantages. Therefore, system research is needed to assess the forest chip utilisation prospects for their environmental quality to secure sustainable forest management. Life-cycle methodology was developed and applied to assess environmental burdens and impacts of the logging and sawmill residues throughout the whole fuel chain from the forest to energy production. According to the study, the energy efficiencies of the forest chip systems are quite high. Net CO2 emissions of the systems are low owing to the low input of external primary energy required to operate the systems. Although wood energy is renewable, it has many similarities with fossil fuels, e.g. as the emissions of the conversion phase are significant. [Copyright &y& Elsevier]

On an international comparison basis, Australia's utilisation of forest residues remains very low. While there are numerous factors contributing to this low utilisation, this is greatly explained by the limited timely and accurate data on availability, quality, and location of residues generated during harvesting operations. This manuscript reports on the development and testing of a new freeware tool called FIELD (Forest Inventory Electronic Live Data), which supports the real-time monitoring and estimation of forestry harvesting residues. As inputs, FIELD uses StanForD pri files and geo-location data extracted from the harvester's onboard computer in combination with locally developed species-specific allometric equations. Using a case study, this paper describes how FIELD works operationally and illustrates the range of support features that the tool can provide to decision-makers by producing real-time data on the availability, quality, and location of harvesting residues. In addition, it is discussed how the tool can contribute to supporting decisions during forest operations associated with the feasibility of residue utilisation in specific site conditions. Our results show that it is possible to estimate the availability of harvesting residues at geo-located sites dynamically, although further testing of the tool is required for a more accurate estimation and monitoring of harvesting residues. [ABSTRACT FROM AUTHOR]

This case study investigates the potentials, greenhouse gas (GHG), and energy performance of forest residue biofuels produced by new and emerging production technologies, which are commercially implemented in Sweden for heavy transport. The biofuel options included are ethanol (ED 95), hydro-processed vegetable oil (HVO), and liquefied biogas (LBG) produced from logging residues in forestry and sawdust generated in sawmills. The calculated life cycle GHG emissions, based on the EU Renewable Energy Directive calculation methodology, for all three pathways are in the range of 6–11 g CO2eq./MJ, corresponding to 88–94% GHG emission reductions as compared to fossil fuel. Critical parameters are the enzyme configuration for ethanol, hydrogen supply systems and bio-oil technology for HVO, and gasifier size for LBG. The energy input is ranging from 0.16 to 0.43 MJ/MJ biofuel and the total conversion efficiency from the feedstock to biofuel, including high-value by-products (excluding heat), varies between 61 and 65%. The study concludes that the domestic biofuel potential from estimated accessible logging residues and sawdust is equivalent to 50–100% of the current use of fossil diesel in heavy-duty road transport in Sweden, depending on the biofuel production technology selected and excluding energy by-products. Thus, an expansion of forest-based biofuels is a promising strategy to meet the ambitious climate goals in the transport sector in Sweden. [ABSTRACT FROM AUTHOR]