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- Ersson, Back Tomas
(författare)
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Advances in the Mechanization of Regenerating Plantation Forests: a Review
- 2020
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Ingår i: Current Forestry Reports. - : Springer Science and Business Media LLC. - 2198-6436. ; 6, s. 143-158
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Forskningsöversikt (refereegranskat)abstract
- Purpose of Review The mechanization of silvicultural work on forest plantations is usually driven by a decreasing supply of motivated labour which increases its relative cost. Mechanization can also result in other advantages like increased effectiveness, higher efficiency, and improved working conditions. The purpose of our review is to examine the last few decades' endeavours to mechanize the regeneration activities of plantation forestry in the southern and northern hemisphere. In this case, regeneration activities include (1) site preparation; (2) tree planting; and (3) stand tending until the crop trees are free from vegetative competition. Recent Findings Originally, the mechanization of silvicultural work commenced in the northern hemisphere, but over the past decades, the most notable progress has been made in the southern hemisphere plantation forests. Although soil preparation is largely mechanized across the globe, tree planting and stand tending activities lag behind because of factors such as global variations in the manner in which they are performed, higher level of complexity, and low-cost competitiveness compared with existing labour-intensive methods. For mechanization of regeneration/silvicultural activities to progress, productive and adaptable machines will be required where economies of scale permit cost-efficient operations. These machines will probably have to be modified to the specific forestry context of different countries. Knowledge of the existing and state-of-the-art regeneration technologies available in both the northern and southern hemispheres is important for foresters to make informed decisions about the selection and application of mechanized regeneration systems.
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- Ersson, Back Tomas
(författare)
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Cost analysis of seedling supply systems adapted for mechanized tree planting: a case study from southern Sweden
- 2022
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Ingår i: Silva Fennica. - : Finnish Society of Forest Science. - 0037-5330 .- 2242-4075. ; 56
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Tidskriftsartikel (refereegranskat)abstract
- 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 con-ditions, 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.
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- Ersson, Back Tomas, et al.
(författare)
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Forest management in northern Fennoscandia: the need for solutions that mitigate conflicts during forest regeneration and increase the use of continuous cover forestry
- 2023
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Ingår i: Silva Fennica. - 0037-5330 .- 2242-4075. ; 57
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Tidskriftsartikel (refereegranskat)abstract
- Today, conflicts often occur in northern Fennoscandia (also known as Sápmi) between forestry and reindeer husbandry. Continuous cover forestry (CCF) is requested by both reindeer herding communities and the general public and is becoming more common, but the forest industry criticizes CCF for lower wood production. Mechanical site preparation (MSP) increases regeneration success and, thus, increases wood production in CCF. To reduce the conflict between forestry and reindeer husbandry, MSP in Sápmi should destroy as little ground lichen as possible. Today, there are no solutions for gentle and lichen-adapted MSP in CCF. Thus, there is a strong need to develop and test new technical solutions that increase regeneration success in a lichen-adapted way during CCF in Sápmi. We suggest that MSP solutions be developed which are gentle, work selectively and function in shelterwoods, gap cuts, and selection cutting stands. We envision that these solutions could fill the gap between the desired adaptivity on the part of the reindeer herding communities and the desired efficiency on the part of the forest industry. Such MSP technology would contribute to increased acceptance of CCF in the forest industry, higher biodiversity, and considerably reduce the conflict between forestry and reindeer herding communities.
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| 7. |
- Ersson, Back Tomas
(författare)
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Forwarding during final felling: work element-specific distributions of driving distances at the stand level
- 2020
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Ingår i: International Journal of Forest Engineering. - : Informa UK Limited. - 1494-2119 .- 1913-2220. ; 31, s. 51-69
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Tidskriftsartikel (refereegranskat)abstract
- Automatic data collection is becoming increasingly common in cut-to-length forest operations. However, only few studies have analyzed automatically collected follow-up data from forwarders. In this study, we analyzed the driving distances of the four work elements Driving empty, Loading drive, Driving loaded, and Unloading drive (the sum of which being Total driven distance) of two forwarders operating in central Sweden. The analysis included finding the most appropriate probability density functions for each distance at the stand level (46 final felling stands in total, with one load as the unit of observation). The results showed that the mean intra-stand Total driven distance ranged 364-2393 m, and that most distances in the majority of the stands were positively skewed. Versatile probability distributions like Generalized Extreme Value and Log-logistic were the most common probability distributions. Our results provide researchers and managers a numeric understanding of the intra- and inter-stand variation of forwarding work. Hence, our study can help spread awareness of this variation to managers and foresters. With this awareness, managers, foresters, and researchers can better understand the pros and cons of follow-up data from forwarders, and how to best use and collect it. Our results can also be used by researchers as high-resolution indata during simulations of forwarding work Additionally, the results can be used as a reference or control when determining the most suitable data distributions in future studies.
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| 8. |
- Ersson, Back Tomas
(författare)
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Hyggesfritt skogsbruk
- 2020
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Omfattande vetenskaplig forskning i Norden de senaste tio åren har visat att hyggesfritt skogsbruk kan vara bättre än trakthyggesbruket på att optimera skogens ekonomiska, ekologiska, och sociala värden. Speciellt intressant för svenska privatskogsägare är den forskning som visar att hyggesfritt skogsbruk kan vara mer lönsamt (generera högre nuvärden) än trakthyggesbruk på marker med låga ståndortsindex, vid höga skogsvårdskostnader, när risken för skogsskador är hög, vid låga rotnetton, och när räntan är hög. Därmed är det viktigt att det svenska skogsbruket fortsätter att utveckla kunnandet och forskningen om hyggesfritt skogsbruk, så att hyggesfri skogsskötsel kan vara en beprövad och flitigt använd metod i Skogssveriges verktygslåda.
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| 9. |
- Ersson, Back Tomas
(författare)
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Innovative productivity improvements in forest operations: a comparative study of the Assortment Grapple using a machine simulator
- 2020
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Ingår i: Journal of Forest Science. - 1212-4834 .- 1805-935X. ; 66, s. 443–451-
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Tidskriftsartikel (refereegranskat)abstract
- Because of generally small log piles, loading forwarders during thinning is time consuming. The Assortment Grapple, an innovative grapple with an extra pair of claws which facilitates the handling of two assortments during one loading crane cycle, has been designed to decrease forwarders’ loading time consumption. A standardized experiment was performed in a virtual thinning stand using a machine simulator with the objectives to form guidelines for working with the Assortment Grapple and to analyse its development potential. Four experienced operators participated in the study. According to the results, the Assortment Grapple’s accumulating function is beneficial only when there are no remaining trees between piles loaded during the same crane cycle. In such cases, none of participating operators lost time, and 3 of 4 operators saved time notably. The problem with the remaining trees is the extra time required to steer the crane tip around them. Therefore, a harvester should place those log piles that are later to be forwarded together in the same space with no remaining trees between the piles. Furthermore, we recommend that the Assortment Grapple’s usability will be improved by adding an own rocker switch on the forwarder’s controls to command the extra claws.
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| 10. |
- Ersson, Back Tomas
(författare)
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Maskinell plantering – analys av planteringsmaskinen PlantmaX potential inom privatskogsbruket
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Privatskogsbruket äger mer än hälften av Sveriges produktiva skogsmark, och intresset för självverksamhet inklusive skogsplantering minskar generellt bland de privata skogsägarna. Sedan hösten 2019 finns planteringsmaskinen PlantmaX, och den utvecklades huvudsakligen för storskogsbruket. Mekanisering av skogsodlingen förväntas på sikt leda till en kostnadsbesparing för skogsbruket, och då är det viktigt att privatskogsbruket också följer med i den mekaniseringstrenden. Syftet med denna analys är att utvärdera PlantmaX:s lämplighet för det svenska privatskogsbruket. Analysen gjordes med hjälp av indata från en mängd källor, både muntliga och skriftliga, från höstarna 2020-2021. En fältstudie av PlantmaX planteringskvalitet visade att planteringsmaskinen i dagsläget ger sämre planteringskvalitet än vid manuell plantering, men bedömningen är att skillnaden troligen inte är avgörande för privata skogsägares acceptans av PlantmaX-konceptet. Dock verkar PlantmaX i dagsläget vara lämpligast på tallmarker pga maskinens svårighet att på ett högkvalitativt sätt plantera i omvänd torva. Uppskattningsvis verkar 4 ha vara den minsta traktstorleken för att PlantmaXkonceptet ska vara konkurrenskraftigt. I och med att medeltrakten på privatägd skogsmark är lägre än 4 ha i både Svealand och Götaland bör dock samordning av trakter vara en möjlighet för att motverka de högre planteringskostnaderna som små trakter medför. Slutbedömningen är att utvecklingspotentialen för PlantmaX plantreringskvalitet är stor, speciellt vid inkorporering av fler sensorer och automatisk identifikation av planteringspunkter. Därför kommer sannolikt PlantmaX framtida planteringskvalitet att öka, något som i sin tur ytterligare kommer att stärka PlantmaX-konceptets lämplighet för det svenska privatskogsbruket.
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