Di Fulvio

Analyses of a single-machine system for harvesting pulpwood and/or energy-wood in early thinnings

Harwarder systems used in roundwood harvesting can be useful at sites where there are low volumes per hectare to be removed or a small total removal volume and where frequent or long-distance machine relocations are required. As well as being suitable for conventional roundwood harvesting, a multi-purpose forest machine can have its configuration changed, so that it can function as a harvester, forwarder, or harwarder, and thus can be considered viable for use in young stands when harvesting pulpwood or energy-wood or combining assortments. Accordingly, in this study we compare the time consumption and productivity of a Ponsse Dual machine system with two harvesting heads and one loading grapple (three machine configurations) when harvesting and forwarding pulpwood and/or energy-wood during early thinning at sites in northern Sweden. Our aim is to analyze costs and profitability under a range of site conditions. Working as a harvester, the machine reached the same level of productivity (trees per hour) whether it was operating with an accumulating felling head or a harvester head able to accumulate some trees; productivity was also independent of work method. The forwarding efficiency was highly correlated with biomass concentration and forwarding distance; whole-tree (tree section) removal over short forwarding distances resulted in the highest productivity. The system achieved the greatest cost-effectiveness when only energy-wood was removed. At current market prices, pulpwood extraction produced the highest net income per hectare, but even this was economically unprofitable. The Ponsse Dual achieves similar productivities to specialized harvesters and forwarders during thinning operations, but at a much higher cost per operating hour. Thus, a single-machine system would need to have ca. 20–30% lower operational costs than the Ponsse Dual to be an economically viable option for early thinning.

Comparison of energy-wood and pulpwood thinning systems in young birch stands

Abstract In early thinnings, a profitable alternative to pulpwood could be to harvest whole trees as energy-wood. In theoretical analyses, we compared the extractible volumes of energy-wood and pulpwood, and their respective gross values in differently aged stands of early birch thinnings at varying intensities of removal. In a parallel field experiment, we compared the productivity at harvest of either pulpwood or energy-wood, and the profitability when the costs of harvesting and forwarding were included. The theoretical analyses showed that the proportion of the total tree biomass removed as pulpwood increased with increasing thinning intensity and stem size. The biomass volume was 1.5–1.7 times larger than the pulpwood volume for a 13.9 diameter at breast height stand and 2.0–3.5 times larger for a 10.4 diameter at breast height stand. In the field experiment, the harvested volume per hectare of energy-wood was almost twice as high as the harvest of pulpwood. The harvesting productivity (trees Productive harvesting Work Time-hour−1) was 205 in the energy-wood and 120 in the pulpwood treatment. The pulpwood treatment generated a net loss, whereas the energy-wood treatment generated a net income, the average difference being €595 ha−1. We conclude that in birch-dominated early thinning stands, at current market prices, harvesting energy-wood is more profitable than harvesting pulpwood.

Comparison of the cost and energy efficiencies of present and future biomass supply systems for young dense forests

The objective was to study the effect of future harvesting and handling technologies on the cost and energy efficiency of supply chains for young dense thinnings. The system costs and energy requirements were modeled using type of stands, products delivered, and transport distances as variables. In total, 14 systems were analyzed, of which five represented future systems. The effects of increasing the payloads of off-road and road transportation of whole tree (WT) parts by 10%, 20%, and 30% were also analyzed. If boom-corridor thinning technologies, optimized bundle-harvesters, and load-compression devices are developed, on average, costs are reduced by 12–27% and 11–30% less energy is required when compared with present systems. For example, at an average harvested tree size of 22 dm3, the supply of WT using future technologies would reduce the cost by up to 15% and the energy requirements by 21%. These effects increase with reduced tree sizes and increased transportation distances. The effects of future technologies are especially significant for tree sizes below 30 dm3, representing a significant part of the potential that could be harvested annually in Sweden. Thus, there should be increased research and development of boom-corridor felling technology, bundle-harvesters, and load-compression devices.

Evaluation of a novel prototype harvester head in early fuel-wood thinnings

The objectives of this study were to evaluate and compare the productivity and operating costs of two harvesting systems for fuel-wood production in dense early thinnings, from stand to road-side: a harvester fitted with a prototype MAMA (brand name) felling head featuring a feed-roller system for compression-processing paired with a standard forwarder; and a harvester with a conventional C16 felling head paired with a forwarder having a grapple-saw for bucking. Because the MAMA head was a prototype, an additional objective was to identify factors that influenced the effectiveness of the MAMA system. The time required for the felling, accumulation, compression-processing and bunching of whole tree-parts using the MAMA head was no greater than that for the felling and bunching of whole trees with the C16 head. The feed-roller system increased the efficiency of the bucking process and also increased the bulk density of the harvested bunches by 47–70%. However, it reduced the overall harvesting yield by 10–23%. Consequently, the harvester productivity with the MAMA head was 12–14% lower than with the C16 head. However, because the MAMA head also increased the forwarder’s load size by 17–24% through its compression-processing of the biomass, it increased the forwarder’s productivity by 12% for an extraction distance of 300 m (one way). Given typical stand conditions and an extraction distance of 300 m, the operating costs of the system with the MAMA head were 1% higher than for the C16 head. In addition, the operating costs of the MAMA system should decrease with the extraction distance. In conclusion, even though the MAMA head is an early prototype that has not been heavily optimized in terms of mass and functionality, its operating costs are already comparable to those of conventional alternatives. With further development, it could significantly reduce the operating costs of harvesting from stand to road-side.

Spatially explicit assessment of roundwood and logging residues availability and costs for the EU28

ABSTRACT Competition for woody biomass between material and energy uses is expected to further increase in the future, due to the limited availability of forest resources and increasing demand of wood for material and bioenergy. Currently, methodological approaches for modeling wood production and delivery costs from forest to industrial gates are missing. This study combines forest engineering, geographically explicit information, environmental constraints and economics in a bottom-up approach to assess cost–supply curves. The estimates are based on a multitude of wood supply systems that were assigned according to geographically explicit forestry characteristics. For each harvesting and transportation system, efficiencies were modeled according to harvesting sites and main delivery hubs. The cost–supply curves for roundwood and logging residues as estimates for current time and for the future (2030) show that there are large regional differences in the potential to increase extraction in the EU28. In most EU Member States, the costs of logging residues extraction increase exponentially already for low levels of mobilization, while extraction of roundwood can be increased to a larger extent within reasonable costs (30–40 

Integrated supply of stemwood and residual biomass to forest-based biorefineries

/m3). The large differences between countries in their harvest potential highlight the importance of spatially explicit analyses.

Effects of sieve size and assortment on wood fuel quality during chipping operations

ABSTRACT The demand for forest biomass as raw material for a wide range of products in the developing bioeconomy is expected to increase. Along with a constant pressure on forestry to increase its productivity, this development has led to the search for new procurement methods and new assortments. The present study assessed innovative supply chain practices, with a particular focus on the integrated supply of stemwood and residual tree parts. The assortments considered included tree sections, long tops, saw logs with stump cores and small whole trees from thinnings. The assessment included geographically explicit modelling of the supply chain operations and estimation of supply cost and energy use for three industrial locations in Northern Sweden. The innovative supply chains were compared to conventional, separate, harvest of stemwood and logging residues. We conclude that integrated harvest of tops and branches with stemwood assortments, as well as whole-tree harvest in early thinnings, has a significant potential to reduce the supply cost for the non-stemwood assortments. Stump wood generally remains the most expensive assortment. The energy use analysis confirms earlier research showing that the energy input is relatively small compared to the energy content of the harvested feedstock. ABBREVIATIONS BWT, bundled whole trees; CTL, cut-to-length; ET, energy thinning; FF, final felling; FT, first thinning; LR, logging residues; LT long tops; ORN, Örnsköldsvik; PCT, pre-commercial thinning; PL, pulpwood; RS, roughly delimbed tree sections; SEK, Swedish currency; SFA, Swedish Forest Agency; SL, sawlogs; SNFI, Swedish National Forest Inventory; SP, stumps; SPC stump core; ST, second thinning; STO, Storuman; UME Umeå; WT, whole small trees;

European and United States Perspectives on Forest Operations in Environmentally Sensitive Areas

Primary residual forest biomass is an important source of energy in Sweden. The fuel quality of this biomass depends on several factors including its moisture content, ash content, and particle size distribution. For optimal combustion, the fuel should have a low content of fine particles. The objective of this study was to compare these quality metrics for five common fuel assortments produced with a drum chipper operated using two different sieve sizes (standard & large). Sieve size had no significant effect on any of the studied fuel quality metrics. On average, 37–63% of the fuel’s dry mass was distributed in particles of 16–31.5 mm. Because logging residues (tops and branches) contain relatively little stem wood, the average fine particle (˂3.15 mm) content of the fuel produced by their chipping was around 10% greater than that of the other studied assortments. Moreover, the ash content of these fines was 2–3 times greater than that of the fines from other assortments. For all assortments, the ash content decreased rapidly with increasing particle size, levelling out at 1.14% for particles of 16–31.5 mm. The average ash contents of the five assortments ranged from 0.84–2.98%. For all assortments, and logging residues in particular, the fuel quality could be significantly increased by screening out fine particles. However, the economic value of such screening depends heavily on the costs of the refining process and the value/utility of the separated fine particles, which should therefore be investigated further.

Spatially explicit LCA analysis of biodiversity losses due to different bioenergy policies in the European Union

ABSTRACT This paper offers a forest operations perspective in environmentally sensitive areas in Europe and the United States. The objective is to help inform key sustainability knowledge gaps in forest operations to reduce impacts on the environment and the equipment operators in these increasingly targeted and difficult to operate in areas. Under existing guidelines and best management practices, the protection of ecosystem services linked to soil, water, wildlife and biodiversity have rightly received the highest considerations. However, the connection between protecting these ecological values, safe operational practices and technological advancements is rarely well articulated. One means to address the operational and technological gap is the selection of equipment and tailor the work conditions to terrain type, forest features and management objectives. To that effect, this paper discusses the environmental, planning, equipment selection and operator considerations and proposes possible solutions and guidelines to contain both the operators’ safety and environmental risks in forest operations.

Benchmarking technical and cost factors in forest felling and processing operations in different global regions during the period 2013–2014

In this study, the potential global loss of species directly associated with land use in the EU and due to trade with other regions is computed over time, in order to reveal differences in impacts between the considered alternatives of plausible bioenergy policies development in the EU. The spatially explicit study combines a life cycle analysis (LCA) for biodiversity impact assessment with a global high resolution economic land use model. Both impacts of domestic land use and impacts through imports were included for estimating the biodiversity footprint of the member states of the (EU28). The analyzed scenarios assumed similar biomass demand until 2020 but differed thereafter, from keeping the growth of demand for bioenergy constant (CONST), to a strong increase of bioenergy in line with the EU target of decreasing greenhouse gas (GHG) emissions by 80% by 2050 (EMIRED) and with the baseline (BASE) scenario falling between the other two. As a general trend, the increasing demand for biomass was found to have substantial impact on biodiversity in all scenarios, while the differences between the scenarios were found to be modest. The share caused by imports was 15% of the overall biodiversity impacts detected in this study in the year 2000, and progressively increased to 24% to 26% in 2050, depending on the scenario. The most prominent future change in domestic land use in all scenarios was the expansion of perennial cultivations for energy. In the EMIRED scenario, there is a larger expansion of perennial cultivations and a smaller expansion of cropland in the EU than in the other two scenarios. As the biodiversity damage is smaller for land used for perennial cultivations than for cropland, this development decreases the internal biodiversity damage per unit of land. At the same time, however, the EMIRED scenario also features the largest outsourcing of damage, due to increased import of cropland products from outside the EU for satisfying the EU food demand. These two opposite effects even out each other, resulting in the total biodiversity damage for the EMIRED scenario being only slightly higher than the other two scenarios. The results of this study indicate that increasing cultivation of perennials for bioenergy and the consequent decrease in the availability of cropland for food production in the EU may lead to outsourcing of agricultural products supply to other regions. This development is associated with a leakage of biodiversity damages to species-rich and vulnerable regions outside the EU. In the case of a future increase in bioenergy demand, the combination of biomass supply from sustainable forest management in the EU, combined with imported wood pellets and cultivation of perennial energy crops, appears to be less detrimental to biodiversity than expansion of energy crops in the EU.