Articles containing the keyword 'productivity'

The paper discusses how the general trend towards increasing growth and productivity in the European societies is expressed also in forestry. It is reflected, for instance, in the increasing production and productivity of forest industries. Technological progress and call for economic growth require great flexibility from all resources. These pressures for effectiveness and production also concern Finnish forestry and forest management. Industrialization, urbanization and development of forestry have increased the pressure to use forests in recreation, preserving human environment and nature conservation in addition to production of timber. Through the development the definition of sustainability has become wider.

• Vehkamäki, E-mail: sv@mm.unknown

Time study on different techniques in nursery pot filling operations at SUA Training Forest in Northern Tanzania was conducted. The results showed that improved tools and work place design significantly decreased the operation time, hence increased productivity. In addition, worker’s comfort was generally increased.

The PDF includes a summary in Finnish.

• Ole-Meiludie, E-mail: ro@mm.unknown
• Pamba, E-mail: gp@mm.unknown

Effects of varying rotation, thinning, fertilization and harvest intensity on the productivity and nitrogen cycle of Scots pine (Pinus sylvestris L.) stand were studied on the basis of computer simulation. The increasing intensity of management increased the loss of nitrogen in the cycle. Short rotation, associated with early thinning by means of the whole tree harvest, proved to be especially detrimental regarding the productivity of the forest ecosystem. Fertilization associated with thinnings is of great importance in maintaining the productivity of a forest ecosystem during an intensive timber harvest.

The PDF includes an abstract in Finnish.

• Kellomäki, E-mail: sk@mm.unknown
• Seppälä, E-mail: ms@mm.unknown

This study deals with the evaluation of logging machines. The analyses were based on the results of a productivity study with special reference to a PIKA 35 processor, a delimber-bucker, working in Kyröskoski forest area in Finland. Factors affecting the productivity of the machine were surveyed. Mathematical models for determining the productivity were developed and their practical applications to the particular problem under study was demonstrated.

The PDF includes an abstract in Finnish.

• Tan, E-mail: jt@mm.unknown

A committee was appointed in 1940 to prepare a proposal for reform of forest taxation. The taxation based on net income of forestry was considered to have limitations, and the actual net income had been observed to be markedly higher than the income that was used in taxation.

The report describes in detail the principles and shortcomings of taxation used since 1922. These include inaccuracies in the forest areas of a woodland estate, and weaknesses in classification of forest land and demand zones. The committee suggests several improvements in calculating the taxable income, which in the new calculations is based on yield on terms of value.

The article includes an abstract in German.

• Metsäverotuksen uudistamiskomitea, E-mail: –

The fellings of small timber have been expanded from seasonal to full-year operation in many areas. A time and motion study was conducted on the felling of pulpwood in different times of the year in seven felling sites in the northernmost Finland. The work was payed per one pulpwood bolt. The output of a one-man teams was larger than 2-6-man teams. Teams of even numbers were more effective than teams of uneven numbers. One-man teams were more popular during summer. The output was largest during the summer. In the late summer the results decrease, because barking of trees becomes more difficult. Shortening of daylight hours begin to shorten the workdays in the autumn. In December, the average working days are about 6 hours. Snow and low temperatures make logging and barking more difficult during the winter. The output was lowest in January, despite that work days are 1 ½ hours longer than in December. It is concluded that pulpwood fellings should be avoided from December to March 15. If the fellings are necessary, the wage system should be changed more flexible than at present. The size of cutter’s lots should be adjusted so, that work periods are not too short. Sufficiently big lots save time spent on travelling between the sites and villages.

The PDF includes a summary in German.

• Maliniemi, E-mail: em@mm.unknown

The aim of the study is to find out 1) whether and how the original moor type can be found out based on vegetation regardless the phase of drainage; 2) whether the different phases of draining can be distinguished based on the vegetation; and 3) is it possible to classify the well drained moors into vegetation types that would reflect the productive capacity of the land.

The data consists of samples collected from ditched areas. There are 11 moor types from two climatic ditching zones. The results show that the original moor type can be determined based on vegetation, the phase of drainage can be determined under some limitations, and the classification for productivity can be done for practical purposes.    

The PDF contains a summary in Finnish. 

• Sarasto, E-mail: js@mm.unknown

The investigation studies the development of a logger’s daily earnings, a sawmill worker’s hourly earnings, saw timber stumpage prices and saw timber export prices, expressed in marks in Finland in 1913-1953, concentrating upon the trends of real value.

Although worker’s earnings in forestry and sawmilling have developed differently especially in the 1920s, the late 1930s and the early 1940s, their general long-time development has been very similar. On the other hand, the stumpage prices increased in real value much sharply than wages before the World War II. The real value of stumpage prices dropped because of economic regulation measures in the 1940s until regulation was abolished and the Korean War boom raised them in 1951, to fall after that. The development depends partly of the development of export prices for sawn timber.

Without changing the distribution of income from exports the real value of labour earnings, measured by export prices, may rise at most at a pace corresponding to the productivity of work. In logging there has been no actual increase in the productivity in the 20th century. As the increase in the productivity in timber transportation has probably been absorbed in increased wages and capital costs in the branch, a rise in forest labour’s real earnings and stumpage is possible only by means of a rise in the productivity of sawmilling or a change in the distribution of export income. It seems that from the end of World War I up to the middle of 1920s this increase of productivity and in export prices of sawn timber was shared only by capital and possibly mill labour. After that up to World War II stumpage prices rose so steeply that they swallowed the entire increase in productivity and reduced capital’s share of the export price. In the 40s the level of earnings followed the trend of productivity in industry, made possible by a sharp reduction in stumpage.

The Acta Forestalia Fennica issue 61 was published in honour of professor Eino Saari’s 60th birthday.
The PDF includes a summary in English.

• Heikinheimo, E-mail: lh@mm.unknown

The aim of the study was to determine the value of common alder (Alnus glutinosa (L.) Gaertn.) in forestry by studying an unusually large alder forest in Kontusaari, an island of the size of 75 hectares in the Southern Finland. The forest is grass-herb forest site type. The coastline of the island is partly flooded. Wood has been harvested mainly for fuel wood. The stands have regenerated easily from stump shoots. The annual volume growth is slightly higher than what would be in Norway spruce (Picae abies (L.) Karst.) or Betula sp. stands, estimated based on growth and yield tables made by Ilvessalo. The site is well suited for common alder, and it is difficult to judge what the yield would be for other species on the site.

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander. The PDF includes a summary in German.

• Hildén, E-mail: nh@mm.unknown

The aim of the study is to define to which extent the productivity of seas in south Finland, and especially the production of animals in sea bottom, can be determined according the forest site classification given to the land areas around the sea, meaning that the productivity class is the same for the forest and the sea. The data for the study has been collected in state owned forests in Evo in middle Finland, in Karelia around the Finnish and Russian border and in southern parts of Karelia.

Where the forests are more barren, VT or Ct types, also the seas have lower productivity, they are oligotrophic or mesotrophic. However, the less barren surrounding forests are not a clear sign of the productivity of the sea. As a result the productivity level of a sea can be estimated relatively good by the fertility of the surrounding areas, though not in all cases. 

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.

The PDF contains a summary in German.

• Valle, E-mail: kv@mm.unknown

Linear optimization model was used to calculate seven wood procurement scenarios for years 1990, 2000 and 2010. Productivity and cost functions for seven cutting, five terrain transport, three long distance transport and various work supervision and scaling methods were calculated from available work study reports. All methods are based on Nordic cut to length conditions. Finland was divided in three parts for description on harvesting conditions. Twenty imaginary wood processing points and their wood procurement areas were created for these areas. The procurement systems, which consists of the harvesting conditions and work productivity function, were described as a simulation model. In the LP-model the wood procurement system has to fulfil the volume and wood assortment requirements of processing points by minimizing the procurement cost. The model consists of 862 variables and 560 restrictions.

Results show that it is economical to increase the mechanical work in harvesting. Cost increment alternatives effect only little on profitability of manual work. The areas of later thinnings and seed tree- and shelterwood cuttings increase on cost of first thinnings. In mechanized work one method, 10-tonne one grip harvester and forwarder, is gaining advantage among other methods. Working hours of forwarder are decreasing opposite to the harverster. There is only little need to increase the number of harvesters and trucks or their drivers from today’s level. Quite large fluctuations in level of procurement and cost can be handled by constant number of machines, by alternating the number of season workers and by driving machines in two shifts. It is possible, if some environmental problems of large-scale summer time harvesting can be solved.

• Rummukainen, E-mail: ar@mm.unknown
• Alanne, E-mail: ha@mm.unknown
• Mikkonen, E-mail: em@mm.unknown

Improvement of Finnish forest industries’ competitiveness in the world markets through productivity increase as branch and plant level requires the search for appropriate comprehensive productivity indicators and the analysis of factors underlying productivity variations. These were the main objectives of the study. The data was based on the information on individual plants in 1974, obtained from the files of Industrial Statistics in the Central Statistical Office in Finland.

The study uses neoclassical average production functions as the starting point and the theory is expanded to cover factors underlying productivity variation when measured with regard to labour, capital, material input, and total factor input. For the measurement of the latter an index formula is suggested which would not necessarily incorporate neoclassical assumptions as they cannot be assumed valid in the Finnish forest industries. The estimation results of average production functions suggest increasing rate of returns in sawmilling but in pulp and paper production evidence remains inconclusive. The elasticity of substitution is unlikely to be constant and the non-homotheticity assumption cannot be rejected.

The productivity variation is, in general, best explained by a relatively simple model with capital-labour ratio, plant size and output quality as explanatory factors. Further trials with input quality, input price ratio, process characteristics, and the rate of capacity utilization improved the models only marginally in most cases, which may have been partly due to the failure to measure the variables successfully.

The cross-section results are compared with those of an earlier time-series study. The estimation results of average production functions yield somewhat different information in the long and short run. Both cross-section and time-series productivity models illustrate the importance of output level in total productivity.

The PDF includes a summary in Finnish.

• Simula, E-mail: ms@mm.unknown

Production of timber in forest stands is described by a production function. The variable inputs of the function are land and growing stock and the output is the annual value growth. The partial derivatives of this production function express the marginal productivity of the land and of auction function express the marginal productivity of the land and of the growing stock. These marginal productivities can be utilized for determination of the need of regeneration and thinning. The stand should be regenerated when the marginal productivity of the land falls below the annual rent of a unit area of open land and thinned when the marginal productivity of the growing stock falls below the annual rent of one unit of growing stock.

The PDF includes a summary in Finnish.

• Kilkki, E-mail: pk@mm.unknown

This is a fourth paper in a series of studies concerning logging in farm forests. The objective was to construct a model representing the productivity per farm of logging for delivery cuts. The first objective was to find out how the productivity of logging should be measured. In the study, combined labour and capital are regarded as the input.

Second object was to consider what variables to use in theory to determine the productivity of logging for delivery cuts. The factors affecting productivity depend on the concept of productivity employed. The productivity per farm of logging in delivery cuts can be determined both by regional and by farm variables. Still considering solely the effect of the quality of labour and capital input, the variables representing the person in charge of the delivery cuts are important explanatory farm variables. Others represent the farm totality (size, lines of production etc.).

Third aim was to develop a statistical-mathematical method suitable for constructing the model. Possible methods include regression analysis, which is, however, not the best method when there is large number of different levels to explain, or factor analysis. The suitable method to use in constructing a model depicting the productivity of a farm, was considered to be to condense the explanatory variables into rotated orthogonal factors. After preliminary correlation analysis, estimates of the factors interpreted as rational were employed as the explanatory variables for selective regression analysis.

Last, the model was tried out against actual material collected per farm, and the hypotheses were tested.

The PDF includes a summary in English.

• Mäkelä, E-mail: jm@mm.unknown

• López, Inland Norway University of Applied Sciences, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, P.O. Box 2400, Koppang, Norway https://orcid.org/0009-0006-6860-3408 E-mail: lucas.lopez@inn.no
• Sjølie, Inland Norway University of Applied Sciences, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, P.O. Box 2400, Koppang, Norway https://orcid.org/0000-0001-8099-3521 E-mail: hanne.sjolie@inn.no
• Nabhani, Inland Norway University of Applied Sciences, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, P.O. Box 2400, Koppang, Norway E-mail: abbas.nabhani@inn.no
• Aguilar, Swedish University of Agricultural Sciences, Department of Forest Economics, SE-901 83 Umeå, Sweden E-mail: francisco.aguilar@slu.se

Uneven-aged forests set certain challenges for cut-to-length harvesting work. It is a challenge to cost-effectively remove larger trees while leaving a healthy understory for regrowth. The study’s aim was to evaluate productivity and costs of harvesting two-storied Silver birch (Betula pendula Roth) and Norway spruce (Picea abies (L.) H. Karst.) stands by creating time consumption models for cutting, and using existing models for forwarding. Damage to the remaining understory spruce was also examined. Four different harvesting methods were used: 1) all dominant birches were cut; 2) half of them thinned and understory was preserved; compared to 3) normal thinning of birch stand without understory; and 4) clear cutting of two-storied stand. Results showed the time needed for birch cutting was 26–30% lower when the understory was not preserved. Pulpwood harvesting of small sized spruces that prevent birch cutting was expensive, especially because of forwarding of small amounts with low timber density on the strip roads. Generally, when taking the cutting and forwarding into account, the unit cost at clear cuttings was lowest, due to lesser limitations on work. It was noted that with increasing removal from 100 to 300 m³ ha^–1, the relative share of initial undamaged spruces after the harvest decreased from 65 to 50% when the aim was to preserve them.  During summertime harvesting, the amount of stem damage was bigger than during winter. In conclusion, two-storied stands are possible to transit to spruce stands by accepting some losses in harvesting productivity and damages on remaining trees.

• Niemistö, Natural Resources Institute Finland (Luke), Natural resources, Kampusranta 9 C, FI-60320 Seinäjoki, Finland https://orcid.org/0000-0002-9152-2108 E-mail: ext.pentti.niemisto@luke.fi
• Korpunen, Norsk institutt for bioøkonomi (NIBIO), Division of Forest and Forest Resources, Department of Forest operations and digitalization, Divisjon for skog og utmark, Avdeling for Driftsteknikk og digitalisering, Høgskoleveien 8, 1433 Ås, Norway https://orcid.org/0000-0001-9749-5684 E-mail: heikki.korpunen@nibio.no
• Nuutinen, Natural Resources Institute Finland (Luke), Production systems, Yliopistokatu 6 B, FI-80100 Joensuu, Finland https://orcid.org/0000-0003-3360-4444 E-mail: yrjo.nuutinen@luke.fi

In Thailand and various other countries tree seedlings are generally planted using simple manual tools, often a ‘planting stick’, but the method requires time-consuming, labour-intensive teamwork. However, use of a ‘planting tube’ allows a single person to perform both the preparation and planting work. Thus, in a classical time study and ergonomic survey we compared the productivity, cost-effectiveness, and ergonomic impact of planting Eucalyptus spp. seedlings using the two tools at the same planting site in Western Thailand. The planting tube method proved to be more productive, more cost-efficient, and less burdensome than the planting stick method (with time and cost requirements of 21 s and €0.0061 per seedling, versus 16.6 s and €0.0463 per seedling, respectively). In conclusion, the planting tube method may be a viable alternative to reduce costs and increase productivity, while maintaining reasonable workloads for the workers, despite the higher purchase price of planting tubes.

• Kaakkurivaara, Department of Forest Engineering, Faculty of Forestry, Kasetsart University, 50 Phahonyothin Rd, Lat Yao, Chatuchak, Bangkok 10900, Thailand E-mail: tomi.kaakkurivaara@gmail.com
• Kaakkurivaara, Department of Forest Engineering, Faculty of Forestry, Kasetsart University, 50 Phahonyothin Rd, Lat Yao, Chatuchak, Bangkok 10900, Thailand E-mail: ffornrm@ku.ac.th

This study’s aim was to identify how the application season and the method of early cleaning (EC), the first stage of multistage pre-commercial thinning (PCT), affected the time consumption in EC and in the subsequent second PCT operation. The worktime in EC was recorded in the spring, summer, and autumn in 22 sites, which were either totally cleaned or point cleaned. Later, these sites were measured at the time of the second PCT. Time consumption was estimated in PCT, based on the removal of the sites. The time consumption in EC was 5.3 productive work hours (pwh) ha^–1, 7.3 pwh ha^–1, and 6.2 pwh ha^–1 respectively in the spring, summer, and autumn. EC in the spring instead of the summer saved 27–30% of working time, depending on the cleaning method. Point cleaning was 0.8 pwh ha^–1 quicker than total cleaning, but the difference was statistically insignificant. The second stage, PCT, was 1 pwh ha^–1 slower to conduct in sites which had been early cleaned in the spring instead of the summer. However, at the entire management program level, EC applied in the spring or autumn instead of the summer saved 11% or 5% respectively of the total discounted costs (3% interest rate) of multistage pre-commercial thinning. Today, the commonest time to conduct EC is in the summer, which was the most expensive of the analyzed management alternatives here. We can expect savings in juvenile stand management in forestry throughout boreal conifer forests by rethinking the seasonal workforce allocation.

• Uotila, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: karri.uotila@luke.fi
• Saksa, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: timo.saksa@luke.fi

The time consumption (TC) of pre-commercial thinning (PCT) varies greatly among sites, stands and forest workers. The TC in PCT is usually estimated by field-assessed work difficulty factors. In this study, a linear mixed model for the TC in PCT was prepared by utilizing forest resources data (FRD). The modelling data included 11 848 and validation data included 3035 worksites with TC information recorded by forest workers within the period of 2008–2018. The worksites represented a range of site and stand conditions across a broad geographical area in Finland. Site and stand characteristics and previous management logically explained the TC in PCT. The more fertile the site, the more working time was needed in PCT. On sites of medium fertility, TC in the initial PCT increased with stand age by 0.5 h ha^–1 yr^–1. Site wetness increased the TC. PCT in summer was more time consuming than in spring. Small areas were more time consuming to PCT per hectare than larger ones. The between-forest worker variation involved in the TC was as high as 35% of the variation unexplained by the TC model. The coefficient of determination in validation data was 19.3%, RMSE 4.75 h ha^–1 and bias –1.6%. The TC model based on FRD was slightly less precise than the one based on field-assessed work difficulty factors (removal quantity and type and terrain difficulty): RMSE 4.9 h ha^–1 vs. 4.1 h ha^–1 (52% vs. 43%). The TC model could be connected to forest information systems where it would facilitate the predictions of the labour costs of PCT without field-assessing work difficulty factors.

• Uotila, Natural Resources Institute Finland (Luke), Natural resources, Latokartanonkaari 9, FI-00790 Helsinki, Finland E-mail: karri.uotila@luke.fi
• Miina, Natural Resources Institute Finland (Luke), Natural resources, Yliopistokatu 6 B, FI-80100 Joensuu, Finland E-mail: jari.miina@luke.fi
• Saksa, Natural Resources Institute Finland (Luke), Natural resources, Survontie 9, FI-40500 Jyväskylä, Finland E-mail: timo.saksa@luke.fi
• Store, Natural Resources Institute Finland (Luke), Bioeconomy and environment, Teknologiakatu 7, FI-67100 Kokkola, Finland E-mail: ron.store@luke.fi
• Kärkkäinen, E-mail: kauko.karkkainen@gmail.com
• Härkönen, Tornator Oyj, Pielisentie 2–6, FI-81700 Lieksa, Finland E-mail: mika.harkonen@tornator.fi

The effect of harvester operator tree selection or prior tree marking in thinning operations on satisfactory results and performance has been widely discussed. In harvester operator tree selection, the machine operator decides on the fly which trees are selected to remain or cut. The objective of the study was to analyze the effect of prior tree marking, thinning method and topping diameter on harvester performance in low-diameter thinning operations. The entire thinning operation was captured using video technology. Overall, 2.36 ha divided into 48 plots with 5202 trees were thinned with an average diameter at breast height (dbh) over bark for all plots of between 12.5 and 14.7 cm. In total, 3122 trees were harvested, resulting in 60% removal of stem number over all plots. The harvester achieved a mean productivity of 7.38 m³ PMH₀^–1 with 1.48 m³ PMH₀^–1 SEM, with stem volume having the major influence on harvesting productivity. Prior tree marking, topping and thinning method did not significantly affect productivity. Without prior tree marking by the foresters, harvesting removal was shifted toward lower diameters. Within the unmarked plots, 7.0% of the residual trees were damaged compared with 3.2% in marked plots.

• Holzleitner, University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan-Straße 82/3, A-1190 Vienna, Austria https://orcid.org/0000-0001-8489-3050 E-mail: franz.holzleitner@boku.ac.at
• Langmaier, University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Silviculture, Peter-Jordan-Straße 82/3, A-1190 Vienna, Austria; Austrian Research Centre for Forests, Department of Forest Growth and Silviculture, Seckendorff Gudent Weg 8, A-1130 Vienna, Austria E-mail: magdalena.langmaier@bfw.gv.at
• Hochbichler, University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Silviculture, Peter-Jordan-Straße 82/3, A-1190 Vienna, Austria E-mail: eduard.hochbichler@boku.ac.at
• Obermayer, University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan-Straße 82/3, A-1190 Vienna, Austria; Agricultural Technical School of Pyhra, Kyrnbergstraße 4, A-3143 Pyhra, Austria E-mail: bernhardt.obermayer@lfs-pyhra.ac.at
• Stampfer, University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan-Straße 82/3, A-1190 Vienna, Austria http://orcid.org/0000-0001-9350-2859 E-mail: karl.stampfer@boku.ac.at
• Kanzian, University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan-Straße 82/3, A-1190 Vienna, Austria http://orcid.org/0000-0002-1198-9788 E-mail: christian.kanzian@boku.ac.at

Tree bucking, defined as the process in which a stem is segmented into shorter logs of varying lengths, has a significant effect on the value adding potential of a forest enterprise. Because of its importance in terms of correct product and length combinations, improper bucking can lead to financial losses. In this study, two treatments (OFF: quality bucking performed by the operator while using hot keys and ON: automatic bucking using the optimized suggestions from the harvester on-board computer; OBC) were tested in a Norway spruce (Picea abies [L.] Karst.) dominated stand located in Germany. Both treatments had the aim to maximize the value of a stem. The research took place in an 80-year old spruce and beech stand under a regenerative cutting. Fully-mechanized harvesting was performed with an 8-wheel Ponsse Bear single-grip harvester equipped with a H8 harvesting head. Results indicated that the product recovery of the two treatments differed by 4% in undamaged trees (no broken tree-tops or stems) to the benefit of manual bucking. However, the revenue of trees subjected to optimized bucking were up to 4% higher (in average 3%) than those of the manual bucking once expressed on a per cubic meter basis. Moreover, the harvesting productivity of the ON treatment was at the maximum 17% higher compared to the OFF treatment. Based on the results from this case study, the use of an optimization software in Norway spruce dominated stands with the aim to maximize the value of single stems showed promising results.

• Labelle, Assistant Professorship of Forest Operations, Department of Ecology and Ecosystem Management, Technical University of Munich, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising, Germany E-mail: eric.labelle@tum.de
• Huß, Assistant Professorship of Forest Operations, Department of Ecology and Ecosystem Management, Technical University of Munich, Hans-Carl-von-Carlowitz-Platz 2, D-85354 Freising, Germany E-mail: linus.huss@gmx.de

Increased growth rates have reduced rotation lengths, increasing the proportion of juvenile wood relative to mature wood, which may negatively affect mechanical performance of sawn timber. However, there is limited information available on the potential impact of breeding for vigour on juvenile wood in Sitka spruce (Picea sitchensis (Bong.) Carrière). In this study, the relationship between vigour (based on total height) and wood properties was investigated in six-year-old Sitka spruce clones grown in two replicated field trials in Ireland. Six clones were evaluated, two clones from each of three vigour (high, intermediate and low) classes. Discs were cut from the base of one ramet per replication for each clone to assess wood quality attributes. Radial tracheid width was significantly and positively correlated with ring width and height, and was negatively correlated with density. The wood of the most vigorous clone had significantly larger ring width with thinner cell walls and wider tracheids than all clones in the two other vigour classes, resulting in lower mean wood density. Latewood properties for all wood attributes measured differed significantly between the two sites. Wood property differences resulted primarily from variation in the proportions of early- and latewood in each annual ring. Additionally, the width of early- and latewood bands in each ring was found to be a more important determinant of juvenile wood quality than the characteristics of the cells within each band. Wood properties differed greatly between clones, suggesting that there is potential to improve juvenile wood properties through selective breeding.

• Donnelly, UCD Forestry, University College Dublin, Belfield, Dublin 4, Ireland E-mail: liam.donnelly@ucdconnect.ie
• Lundqvist, Innventia Ab, Drottning Kristinas väg 61, SE-114 86 Stockholm, Sweden E-mail: svenolof.lundqvist@innventia.com
• O’Reilly, UCD Forestry, University College Dublin, Belfield, Dublin 4, Ireland E-mail: conor.oreilly@ucd.ie

Competitive interactions in clonal forestry are not well understood and this needs to be addressed to develop better deployment strategies. Eight juvenile Sitka spruce (Picea sitchensis (Bong.) Carriére) clones were grown in monoclonal and clonal mixtures in a field experiment for three years to assess the effects of genetic diversity on shoot growth, above- and below-ground biomass partitioning and crown characteristics. Shoot elongation was measured throughout the growing season, while diameter was measured twice annually in May and December. After the third year, crown silhouette area was estimated from digitised images for one ramet per plot and ramets were then destructively harvested. Deployment × clone interactions were observed for tree height and diameter with reductions observed in mixed plots. Mixed plots had significantly greater height and diameter heterogeneity and more asymmetrical competition than monoclonal plots. Results from this study demonstrate that stem growth can be significantly altered when clones are planted in multi-clonal mixtures but for most clones, deployment-type will not significantly reduce their productivity.

• Donnelly, UCD Forestry, University College Dublin, Belfield, Dublin 4, Ireland E-mail: liam.donnelly@ucdconnect.ie
• Grant, UCD Forestry, University College Dublin, Belfield, Dublin 4, Ireland E-mail: olga.grant@ucd.ie
• O’Reilly, UCD Forestry, University College Dublin, Belfield, Dublin 4, Ireland E-mail: conor.oreilly@ucd.ie

Commercial forests require early cleaning to ensure the unhindered and uniform growth of crop trees. In order to be cost effective, non-crop vegetation should be uprooted to prevent their recovery. Performing this work manually is a labour-intensive task but it can be done mechanically. We evaluated the efficiency of two uprooting devices in direct seeded Scots pine (Pinus sylvestris L.) stands ca. 1 m tall. Productivity and quality of the uprooting work was investigated across eight stands and ca. 160 sample plots in northern Karelia, eastern Finland. Time consumption of the uprooters was analyzed through a linear regression model and the work quality through a multilevel multivariate model in terms of the number of individual Scots pine seedlings, processing units (i.e., a bunch of seedlings to be harvested in the future) and broadleaves. The productivity of the narrower modified device was significantly better in terms of time consumption than the wider original device. Work quality did not differ significantly between devices when stand characteristics, regeneration success and pre-existing damage were taken into account. Results indicate that mechanical uprooting devices may be further developed to a cost-effective alternative to motor-manual techniques for the early cleaning of direct seeded commercial Scots pine stands.

• Hallongren, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: heidi.hallongren@luke.fi
• Kankaanhuhta, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: ville.kankaanhuhta@luke.fi
• Kukkonen, University of Eastern Finland, School of Forest Sciences. P.O. Box 111, FI-80101 Joensuu, Finland E-mail: mikaelkukkonen@hotmail.com

Early thinnings are laborious and costly. Thus forest companies are searching for cost and time efficient ways to carry out this task. The study’s purpose was to determine the productivity of the EF28 accumulating energy wood harvesting head in harvesting small-diameter hornbeam (Carpinus betulus L.) undergrowth trees and evaluate the effect of its multi-tree handling (MTH) capacity on time consumption. The harvester was a wheeled, three-axle Komatsu 911. A time study of 7.1 hours on 19 plots, with a total area of 0.76 ha was conducted. On average, the harvested tree volume was 8 dm³ and the stand density was 2666 trees/ha. The productivity was modelled with MTH conduction, mean diameter at breast height and the number of trees handled per cycle as independent variables. On average, MTH took 27% longer per cycle, increased extracted volume per cycle by 33% and consequently increased productivity with 5.0%. In 71.9% of the cycles more than one tree was handled and if so, dimensions were smaller than in single-tree handling (5.8 cm vs. 12.0 cm). Maximum felling diameter of 23 cm was about 15% smaller than in softwood (according to the manufacturer’s specifications) and the driver didn’t exploit the EF28’s theoretical potential in terms of trees handled per cycle. It can be concluded that the head could significantly improve productivity in small-diameter wood procurement.

• Erber, Addresses University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan Straße 82/3, A-1190 Vienna, Austria E-mail: gernot.erber@boku.ac.at
• Holzleitner, Addresses University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan Straße 82/3, A-1190 Vienna, Austria E-mail: franz.holzleitner@boku.ac.at
• Kastner, Addresses University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan Straße 82/3, A-1190 Vienna, Austria E-mail: maximilian.kastner@boku.ac.at
• Stampfer, Addresses University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan Straße 82/3, A-1190 Vienna, Austria E-mail: karl.stampfer@boku.ac.at

The primary aim of this study was to clarify the chipping productivity and fuel consumption of tractor-powered and truck-mounted drum chippers when chipping pine pulpwood at a terminal. The secondary aim was to evaluate the impact of wood storage time on the chemical and physical technical specifications of wood chips by chipping pulpwood from eight different storage time groups, using Scots pine (Pinus sylvestris) pulpwood stems logged between 2 and 21 months previously at the terminal with the above-mentioned chippers. Thirdly, the impact of sieve mesh size on the particle size distribution of wood chips from different age groups was compared by using an 80 mm × 80 mm sieve for a tractor-powered chipper and a 100 mm × 100 mm sieve for a truck-mounted chipper. With both chippers, the chipping productivity grew as a function of grapple load weight. The average chipping productivity of the tractor-powered chipper unit was 19 508 kg (dry mass) per effective hour (E₀h), and for the truck-mounted chipper the average productivity was 31 184 kg E₀h^–1. The tractor-powered drum chipper’s fuel consumption was 3.1 litres and for the truck-mounted chipper 3.3 litres per chipped 1000 kg (dry mass). The amount of extractives or volatiles did not demonstrate any statistically significant differences between storage time groups. The particle size distributions with both chippers were quite uniform, and the storage time of pulpwood did not have a significant effect on the particle size distribution in any chip size classes. One reason for this might be that the basic density of chipped wood was homogenous and there was no statistical difference between different storage times. The use of new sharp knives is likely to have affected chip quality, as witnessed by the absence of oversized particles and the moderate presence of fines. The use of narrower 80 mm × 80 mm sieves on Scots pine material does not seem to offer any benefit compared to 100 mm × 100 mm from the chip quality point of view.

• Laitila, Natural Resources Institute Finland (Luke), Bio-based business and industry, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: juha.laitila@luke.fi
• Routa, Natural Resources Institute Finland (Luke), Bio-based business and industry, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: johanna.routa@luke.fi

• Laine, Finnish Forest Research Institute (METLA), Suonenjoki Unit, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: tiina.laine@metla.fi
• Saarinen, Finnish Forest Research Institute (METLA), Suonenjoki Unit, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: veli-matti.saarinen@metla.fi

• Ersson, Department of Forest Biomaterials and Technology, SLU, SE-90183 Umeå, Sweden E-mail: back.tomas.ersson@slu.se
• Bergsten, Department of Forest Biomaterials and Technology, SLU, SE-90183 Umeå, Sweden E-mail: urban.bergsten@slu.se
• Lindroos, Department of Forest Biomaterials and Technology, SLU, SE-90183 Umeå, Sweden E-mail: ola.lindroos@slu.se

• Uotila, Finnish Forest Research Institute, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: karri.uotila@metla.fi
• Saksa, Finnish Forest Research Institute, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: timo.saksa@metla.fi
• Rantala, Metsä Group, Lielahdenkatu 10, FI-33400 Tampere, Finland E-mail: juho.rantala@metsagroup.com
• Kiljunen, Metsähallitus, Asemakatu 7, FI-70107 Kuopio, Finland E-mail: nuutti.kiljunen@metsa.fi

• Manner, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden E-mail: jussi.manner@slu.se
• Nordfjell, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden E-mail: tomas.nordfjell@slu.se
• Lindroos, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden E-mail: ola.lindroos@slu.se

• Spinelli, CNR IVALSA, Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy E-mail: spinelli@ivalsa.cnr.it
• Cavallo, CNR IVALSA, Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy E-mail: e.cavallo@imamoter.cnr.it
• Eliasson, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: lars.eliasson@skogforsk.se
• Facello, CNR IVALSA, Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy E-mail: a.facello@ima.to.cnr.it

• Costa, CRA ING, Monterotondo Scalo (Roma), Italy E-mail: cc@nn.it
• Menesatti, CRA ING, Monterotondo Scalo (Roma), Italy E-mail: pm@nn.it
• Spinelli, CNR IVALSA, Sesto Fiorentino (FI), Italy E-mail: spinelli@ivalsa.cnr.it

• Spinelli, CNR IVALSA, Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy E-mail: spinelli@ivalsa.cnr.it
• Magagnotti, CNR IVALSA, Via Biasi 75, S. Michele all’Adige (TN), Italy E-mail: nm@nn.it
• Paletto, CNR IMAMOTER, Strada delle Cacce 73, Torino, Italy E-mail: gp@nn.it
• Preti, CNR IMAMOTER, Strada delle Cacce 73, Torino, Italy E-mail: cp@nn.it

• Lafleur, NSERC-UQAT-UQAM Industrial Chair in Sustainable Forest Management, Université du Québec en Abitibi-Témiscamingue, 445 boul. de l’Université, Rouyn-Noranda, QC J9X 5E4, Canada E-mail: benoit.lafleur@uqat.ca
• Fenton, NSERC-UQAT-UQAM Industrial Chair in Sustainable Forest Management, Université du Québec en Abitibi-Témiscamingue, 445 boul. de l’Université, Rouyn-Noranda, QC J9X 5E4, Canada E-mail: njf@nn.ca
• Paré, Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, QC G1V 4C7, Canada E-mail: dp@nn.ca
• Simard, Département de Géographie, Université Laval, Pavillon Abitibi-Price, 2405 rue de la Terrasse, Québec, QC G1V 0A6, Canada E-mail: ms@nn.ca
• Bergeron, NSERC-UQAT-UQAM Industrial Chair in Sustainable Forest Management, Université du Québec en Abitibi-Témiscamingue, 445 boul. de l’Université, Rouyn-Noranda, QC J9X 5E4, Canada E-mail: yb@nn.ca

• Nuutinen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: yrjo.nuutinen@metla.fi
• Väätäinen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: kv@nn.fi
• Asikainen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: aa@nn.fi
• Prinz, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: rp@nn.fi
• Heinonen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: jh@nn.fi

• Rantala, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: juho.rantala@metla.fi
• Harstela, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: ph@nn.fi
• Saarinen, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: vms@nn.fi
• Tervo, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: lt@nn.fi

• Laitila, Finnish Forest Research Institute, Joensuu Research Unit, Joensuu, Finland E-mail: juha.laitila@metla.fi

• Spinelli, CNR/IVALSA, Via Madonna del Piano - Palazzo F, I-50019 Sesto Fiorentino (FI), Italy E-mail: spinelli@ivalsa.cnr.it
• Nati, CNR/IVALSA, Via Madonna del Piano - Palazzo F, I-50019 Sesto Fiorentino (FI), Italy E-mail: cn@nn.it
• Magagnotti, CNR/IVALSA, Via Madonna del Piano - Palazzo F, I-50019 Sesto Fiorentino (FI), Italy E-mail: nm@nn.it

• Hökkä, Finnish Forest Research Institute, Rovaniemi Research Station, PO Box 16, 96301 Rovaniemi, Finland E-mail: hannu.hokka@metla.fi
• Penttilä, Finnish Forest Research Institute, Rovaniemi Research Station, PO Box 16, 96301 Rovaniemi, Finland E-mail: tp@nn.fi

The consensus on the factors affecting harvester productivity is generally widely acknowledged in the discipline. However, research results regarding the effect of forking on productivity are diverse. Some studies show that harvester productivity is halved when harvesting double stems compared to single-stem trees, while other studies indicate that forking does not necessarily decrease harvester productivity. These differences in study results can depend on what is considered forking. In our study, the forking occurred above the breast-height level. We defined codominant stems as forked trees too large to be multi-tree handled. In contrast, we defined double crowns as forked trees that could be multi-tree handled. The objective of our study was to analyse how the presence of codominant stems and/or double crowns affects harvester time consumption. The study was conducted in Sweden in 2022, involving two operators and two large harvesters. The 45-year-old Pinus contorta Douglas ex Loudon-dominated stand was clearcut during the study. We found that the presence of codominant stems doubles harvester time consumption per tree, while double crowns had only a minor impact on harvester time consumption. Additionally, total time consumption increased linearly with increasing diameter at breast height. Based on these findings, we recommend that forked trees be removed already during thinning when they can still be time-efficiently multi-tree handled. Dealing with forked trees later during the rotation cycle, when they are too large for multi-tree handling, is excessively time-consuming.

• Manner, Skogforsk, Uppsala Science Park, 751 83 Uppsala, Sweden https://orcid.org/0000-0002-4982-3855 E-mail: jussi.manner@skogforsk.se
• Lundström, Skogforsk, Uppsala Science Park, 751 83 Uppsala, Sweden E-mail: hagos.lundstrom@skogforsk.se

The forwarder loads processed wood and transports it to a landing. Productivity of forwarding could be improved by increasing driving speed, but difficult forest terrain limits this. According to current literature, crane work is the most time-consuming work element of forwarding, so improving crane work productivity is essential for improving forwarding productivity. One way to do this is through automation of recurrent boom movement patterns, or alternatively automation can be used to ease crane work. When using conventional boom control (CBC), the operator manually controls each of the independent boom joint movements and combines them to achieve a desired boom tip movement, but boom tip control (BTC) allows the operator to control boom tip movements directly. The objective of the present study was to examine whether BTC facilitates crane work and affects the slopes of learning curves for beginner-level forwarder operators. The study was carried out using a standardised test routine to evaluate effects of two fixed factors, system (levels: CBC, BTC) and point of time (four levels), on five dependent variables. Four of the five dependent variables measured ease of boom control and the fifth measured crane work productivity. The results showed that there were no significant differences in the slopes of learning curves between the systems but the BTC did increase crane work productivity and made boom control easier.

• Manner, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden http://orcid.org/0000-0002-4982-3855 E-mail: jussi.manner@skogforsk.se
• Gelin, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: olle.gelin@skogforsk.se
• Mörk, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: anders.mork@skogforsk.se
• Englund, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: martin.englund@skogforsk.se

• Kärhä, Stora Enso Wood Supply Finland, Talvikkitie 40 C, FI-01300 Vantaa, Finland E-mail: kalle.karha@storaenso.com

• Schweier, Albert-Ludwigs-University Freiburg, Institute of Forest Utilisation and Work Science, Freiburg, Germany E-mail: janine.schweier@fobawi.uni-freiburg.de
• Becker, Albert-Ludwigs-University Freiburg, Institute of Forest Utilisation and Work Science, Freiburg, Germany E-mail: gb@nn.de

• Jylhä, Finnish Forest Research Institute, Kannus Research Unit, P.O. Box 44, FI-69101 Kannus, Finland E-mail: paula.jylha@metla.fi
• Laitila, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: jl@nn.fi