Articles by Jussi Manner

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

Because today’s tree planting machines do a good job silviculturally, the Nordic forest sector is interested in finding ways to increase the planting machines’ productivity. Faster seedling reloading increases machine productivity, but that solution might require investments in specially designed seedling packaging. The objective of our study was to compare the cost-efficiency of cardboard box concepts that increase the productivity of tree planting machines with that of today’s two most common seedling packaging systems in southern Sweden. We modelled the total cost of these five different seedling packaging systems using data from numerous sources including manufacturers, nurseries, contractors, and forest companies. Under these southern Swedish conditions, the total cost of cardboard box concepts that increase the productivity of intermittently advancing tree planting machines was higher than the cost of the cultivation tray system (5–49% in the basic scenario). However, the conceptual packaging system named ManBox_fast did show promise, especially with increasing primary transport distances and increased planting machine productivities and hourly costs. Thus, our results show that high seedling packing density is of fundamental importance for cost-efficiency of cardboard box systems designed for mechanized tree planting. Our results also illustrate how different factors in the seedling supply chain affect the cost-efficiency of tree planting machines. Consequently, our results underscore that the key development factor for mechanized tree planting in the Nordic countries is the development of cost-efficient seedling handling systems between nurseries and planting machines.

• Ersson, SLU, School of Forest Management, SE-739 21 Skinnskatteberg, Sweden https://orcid.org/0000-0003-2442-7482 E-mail: back.tomas.ersson@slu.se
• Sundblad, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: lars-goran.sundblad@skogforsk.se
• Manner, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden https://orcid.org/0000-0002-4982-3855 E-mail: jussi.manner@skogforsk.se

Crane work is the most time-consuming work element in forwarding. Hence, assist systems like boom-tip control are of interest. The first commercially available boom-tip control for forwarders was introduced in 2013. In this study we analysed whether replacing conventional boom control (CBC) with John Deere’s version of boom-tip control (named Intelligent Boom Control, IBC), increases crane-work productivity. We used data automatically gathered from 10 final-felling stands, covering typical logging conditions for southern, central and northern Sweden. Two John Deere 1510E and two John Deere 1910G forwarders were operated by seven experienced operators during the follow-up study, covering 1238 loads in total. A split-plot design was applied to isolate effects of the boom-control system being used (CBC, IBC). We found that using IBC for loading work (crane work and driving included) saved 5.2% of productive machine time compared to using CBC (p ≤ 0.05). The corresponding saving when using IBC for unloading work was 7.9% (p ≤ 0.05). Depending on geophysical factors, this corresponds to approximately 4% savings in productive machine time for forwarding as a whole, including pure transport (with and without load). Moreover, the study introduced in cut-to-length context a novel field-study design to collect a large follow-up dataset in the course of ordinary forwarding operations. We found the study design to be a cost-efficient way to combine the representativeness of conventional follow-up datasets with the ability to establish causal relationships. Establishment of causal relationships has traditionally been possible only through observational time studies or standardized experiments.

• 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
• 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

Recent developments in on-board technology have enabled automatic collection of follow-up data on forwarder work. The objective of this study was to exploit this possibility to obtain highly representative information on time consumption of specific work elements (including overlapping crane work and driving), with one load as unit of observation, for large forwarders in final felling operations. The data used were collected by the John Deere TimberLink system as nine operators forwarded 8868 loads, in total, at sites in mid-Sweden. Load-sizes were not available. For the average and median extraction distances (219 and 174 m, respectively), Loading, Unloading, Driving empty, Driving loaded and Other time effective work (PM) accounted for ca. 45, 19, 8.5, 7.5 and 14% of total forwarding time consumption, respectively. The average and median total time consumptions were 45.8 and 42.1 minutes/load, respectively. The developed models explained large proportions of the variation of time consumption for the work elements Driving empty and Driving loaded, but minor proportions for the work elements Loading and Unloading. Based on the means, the crane was used during 74.8% of Loading PM time, the driving speed was nonzero during 31.9% of the Loading PM time, and Simultaneous crane work and driving occurred during 6.7% of the Loading PM time. Time consumption per load was more strongly associated with Loading drive distance than with extraction distance, indicating that the relevance of extraction distance as a main indicator of forwarding productivity should be re-considered.

• Manner, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: jussi.manner@skogforsk.se
• Palmroth, John Deere Forestry, P.O. Box 472, FI-33101 Tampere, Finland E-mail: PalmrothLauri@JohnDeere.com
• Nordfjell, Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, SE-901 83 Umeå, Sweden E-mail: tomas.nordfjell@slu.se
• Lindroos, Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, SE-901 83 Umeå, Sweden E-mail: ola.lindroos@slu.se

• 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

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

The productivity of cut-to-length machine operators exhibits a significant disparity, with the most productive individuals demonstrating twice the efficiency of their less productive counterparts. This discrepancy is largely attributed to variations in work methods. While supervised training has proven effective in streamlining work methods and enhancing productivity, the availability of forest-machine instructors for supervision is limited. Intelligent coaching systems (ICS) are periodically proposed to address this constraint. ICS are computer-based aids that offer machine operators real-time feedback on their work and guide them on how to rationalize their work. The successful implementation of ICS initially requires the development of systems for automatic work-element detection (AWED). Therefore, this article explores the history, current status, and technological possibilities of AWED. Additionally, key features of ICS are briefly reviewed. Lastly, a broader, interdisciplinary discussion is initiated on how to strategically allocate limited research resources. Questions surrounding the feasible ambition level for ICS and AWED are raised, prompting considerations for the next steps in research and development.

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

• Ersson, Swedish University of Agricultural Sciences (SLU), School of Forest Management, SE-739 21 Skinnskatteberg, Sweden https://orcid.org/0000-0003-2442-7482 E-mail: back.tomas.ersson@slu.se
• Hansson, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden https://orcid.org/0000-0002-9788-1734 E-mail: linnea.hansson@skogforsk.se
• Manner, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden https://orcid.org/0000-0002-4982-3855 E-mail: jussi.manner@skogforsk.se
• Sandström, Swedish University of Agricultural Sciences (SLU), Department of Forest Resource Management, SE-901 83 Umeå, Sweden https://orcid.org/0000-0003-0977-0071 E-mail: per.sandstrom@slu.se
• Sonesson, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala, Sweden https://orcid.org/0000-0002-2018-7496 E-mail: johan.sonesson@skogforsk.se