Productivity in Mechanizing Early Tending in Spruce Seedling Stands

According to National Forest Inventory data, there is an urgent need for tending seedling stands of at least 700,000 ha and a need for 1 million ha in the next few years in Finland. The motivation for forest owners to conduct pre-commercial silvicultural operations is low due to the associated high costs. Especially the costs of tending and clearing operations after the regeneration of the stand have been increasing. In addition, the availability of labor is a restricting factor due to the high seasonality of silvicultural works. In the 2000s, several solutions for the mechanization of tending have been proposed. These are based on the use of harvester or a forwarder as a base machine. Typically, light weight base machines are favored to reduce the hourly cost of operations and the impacts on the remaining seedlings. There have been challenges with the high speed of the cutting device, which increases the risk of damages to the head and the ignition of forest fires when the circular saw or chain hits stones, for example. In addition, the chain can become dislocated due to bending forces caused by stumps. Cutlink has presented a low RPM solution based on rotating cone-shaped shears that cut 50–100 cm wide corridors between and around seedlings. In this study, the productivity of mechanized tending with Cutlink´s device compared to manual tending was evaluated in spruce seedling stands in central Finland. The productivity, fuel consumption and quality of the seedling stand after the operation were measured. In early tending, the productivity of motor manual tending was notably better than when using the Cutlink device. Crucial factors for the competitiveness of a mechanized alternative include the annual working hours and finding suitable working areas for the machine. Additional work for the device and base machine can also be found in the clearing of forest road sides

Forwarding of Whole Trees After Manual and Mechanized Felling Bunching in Pre-Commercial Thinnings

This paper examines the forwarding productivity of energy wood thinnings. The objectives of the study were to: compare the forwarding productivity following either manual or mechanized felling of whole trees and create productivity models for forwarding. The time consumption of the work phases in forwarding, following manual and mechanized cutting, was formulated by applying a regression analysis, in which the independent variables were cutting removal (m3/ha) and forwarding distance (m). The final calculation unit for time consumption in each of the work elements was second (s) per solid cubic meter (m3). Time studies were carried out using two Timberjack 810B forwarders. According to these results, forwarding productivity following mechanized energy wood cutting was significantly higher compared to productivity after manual cutting. Mechanized cutting by the harvester enables the felling and bunching of whole trees into large grapple loads close to the side of the strip road, which clearly improves the output of forwarding thereby helping to reduce costs. When the forwarding distance was 250 m, accumulation of energy wood was 60 m3/ha, and load size was 6 m3, the forwarding productivity following mechanized cutting was 11.9 m3/E0h and 7.1 m3/E0h after manual cutting

Effect of Forest Structure on Operational Efficiency of a Bundle-Harvester System in Early Thinnings

The objective of the study was to improve knowledge on effects of harvested tree size and density of undergrowth on the operational efficiency of a bundle-harvester that produces 2.6 m long bundles, with ca. 60–70 cm diameter, in early fuel wood thinnings. In total 26 time study plots were marked out in 30 to 35 year old Scots pine dominated stands with initial density of 2800–9300 trees/ha and stem size range of 15–43 dm3. Ten of the units, randomly chosen, were precleared of undergrowth trees (≤2.5 cm at breast height diameter) prior to harvesting. There were no significant differences between treatments (preclearing vs. no preclearing) in properties or operational efficiency of the harvested and remaining stands. The average height of cut trees and volume of cut stems were 7.4 m and 16.2 dm3, respectively, and on average, 3554 trees/ha were removed. The bundles had a mean fresh mass of 439 kg and the mass was correlated to the proportion of birch trees cut. The productivity was, on average, 3.1 OD t/PM0H (6.6 fresh t/PM0H; 15.1 bundles/PM0H, where PM0H is productive machine hours, without delays) and was modeled with the harvested stem volume (dm3) as a single independent variable. The study provides complementary knowledge to earlier studies of the system’s performance, especially for harvesting stems <30 dm3. Its productivity was limited by the cutting efficiency and could probably be significantly increased by using a felling and bunching head that could cut and accumulate trees during continuous boom movements. Thus, it would be informative to evaluate such a system in various early thinning stand conditions, including assessments of its manoeuvrability in more difficult terrain

Efficiency of Integrated Grinding and Screening of Stump Wood for Fuel at Roadside Landing with a Low-Speed Double-Shaft Grinder and a Star Screen

Impurities in harvested stumps are a quality problem because high levels of mineral contaminants decrease the effective heating value of the stump wood, and can also affect ash melting behaviour during combustion, leading to sintering and drift problems. The aim of this case study was to clarify the productivity and screening efficiency of the Kompetech Crambo 6000 low-speed double-shaft grinder equipped with a Komptech star screen, in the integrated grinding and screening of Norway spruce and Scots pine stumps for fuel at a roadside landing, when using two different sieve sizes (250 x 320 mm and 180 x 180 mm screen baskets). Furthermore, we studied the fuel consumption of the Crambo 6000 grinder, ash content and particle size distribution of ground stump wood, and ash content and particle size distribution of the screening reject. In addition, the heating value of the produced hog fuel and screening reject were analysed. During the time of the studies, both the grinder and star screen were operating well and there were no delays due to machine breakdowns. The mobile Crambo 6000 grinder was also capable of operating well in constricted roadside landings. The quality of the produced hog fuel was high, due to low ash content (0.4–2.3%), and this highlights the significance of screening to guarantee sufficient quality when processing stump fuel. The ash content of the screening reject was 32.4–74.7%, and the effective heating value was 5.2–13.4 MJ/kg. The effective heating value of the produced hog fuel was 17.9–19.9 MJ/kg. The average grinding productivity, when using the 250 x 320 mm screen basket, was 162 loose m3 per effective hour, and the fuel consumption of the grinder was 0.44 litres per loose m3. With a narrower screen, the average grinding productivity was 101 loose m3 per effective hour, and the fuel consumption of the grinder was 0.75 litres per loose m3

Studies and demonstration on the use of a bundle-harvester system in early fuel wood thinnings

Luken kirjat, raportit, oppaat ja esitteet. INFRES, demo report 15European Commission – FP7 programme; INFRES – Innovative and effective technology and logistics for forest residual biomass supply in the EU (311881)201

Pienpuuhakkeen kustannustekijät ja toimituslogistiikka

Raportin taitto: Maija HeinoHankkeessa kehitettiin VMI:n koeala- ja monilähdeinventointiaineistoon sekä metsäyhtiöiden leimikkotietoihin perustuva nuorten metsien energiapuun kertymä- ja korjuukustannusten laskentamenetelmä. Kertymälaskelmissa hankinta-alueen säde oli 100 km tieverkkoa pitkin ja hankinta-alueet sijaitsivat Joensuun, Kouvolan, Valkeakosken Vaasan, Jyväskylän, Rovaniemen ja Kajaanin ympäristössä. Pienpuun saatavuudelle määritettiin viisi eri tasoa ekologis-taloudellisilla rajoitteilla. Laskenta-alueista Kouvolan ympäristössä pienpuun kertymä oli suurin ja Vaasan ympäristössä pienin. Vaasan ympäristössä kertymä 100 kilometrin säteellä oli eri kertymärajoitteilla 50 000 210 000 m3 vuodessa ja Kouvolan alueella 230 000 790 000 m3 vuodessa. Joensuun, Jyväskylän ja Kajaanin ympäristössä kertymät olivat 120 000 500 000 m3 vuodessa. Kertymälaskelmissa käytetyt rajoitteet vaikuttivat energiapuukertymän ohella puulajisuhteisiin. Kasvupaikan viljavuudelle asetetut minimirajoitteet vähensivät männyn osuutta ja lisäsivät koivun ja muiden lehtipuiden osuutta kokonaiskertymästä. Erot miestyönä tai koneella tehdyn pienpuun kaato-kasauksen kustannusten välillä ovat pienet, mutta kun huomioidaan metsäkuljetuksen tehostuminen koneellisen kaadon jäljiltä, on koneellinen korjuu miestyötä edullisempaa. Käyttöpaikkahintoja tarkasteltaessa ero kalleimman ja halvimman alueen välillä oli 15 %. Valkeakoskella ja Kouvolassa oli halvimmat käyttöpaikkahinnat. Seuraavaksi edullisimmat alueet olivat Jyväskylä, Joensuu ja Kajaani. Rovaniemellä oli korkein käyttöpaikkahinta ja Vaasassa toiseksi korkein. Koneelliseen kaato-kasaukseen ja kokopuun käyttöpaikkahaketukseen perustuva korjuuketju oli menetelmävertailussa edullisin kokopuuhakkeen tuotantomenetelmä. Pienpuulle maksettavat ns. Kemera-tuet parantavat pienpuuhakkeen kilpailukykyä hakkuutähdehakkeeseen verrattuna. Ilman tukia pienpuu ei pärjää hintavertailussa hakkuutähdehakkeen kanssa. Pienpuuhakkeen ero hakkuutähdehakkeen kustannuksiin syntyy kaato-kasausvaiheessa, joka maksaa 12 15 e/m3. Siksi toiminnan tehostaminen tulisi kohdistua juuri tähän vaiheeseen. Muiden kustannustekijöiden osalta pienpuuhake on kilpailukykyistä hakkuutähteeseen verrattuna

Productivity and Cost-Efficiency of Bundling Logging Residues at Roadside Landing

The aim of this case study was to clarify the productivity and cost of a system based on bun- dling logging residues at the roadside landing with the forwarder-mounted logging residue bundler. In order to find the bundling productivity, a set of time studies was carried out, in which several working techniques were tested and evaluated. The cost-efficiency of the roadside bundling system was compared with the conventional bundling system, wherein the logging of residue logs is made directly in the terrain and, after bundling, the logging residue logs are forwarded to the roadside landing with a forwarder. The harvesting cost (bundling and forwarding) of the extracted wood biomass to the roadside landing was calculated for bundling systems using time study data obtained from this study and productivity models and cost parameters acquired from the literature. The productivity of roadside bundling ranged from 48 to 53 logging residue logs per effective working hour (E0h), depending on the working technique used, and the mean time required to produce one logging residue log ranged from 83.6 to 92.3 seconds (E0h). The harvesting costs of the logging residue logs (€/m3) at the roadside landing were 11.5–13.7 €/m3 for the system based on bundling in terrain and 10.8–17.7 €/m3 for the system based on bundling at the roadside landing, when the forwarding distance was in the range 100–600 m and the removal of logging residues was in the range 30–90 m³/ha (m3 = solid cubic metre). According to our results, bundling at the roadside landing allowed a reduction in harvesting costs, when the forwarding distance of the logging residues was 100 m or less and removal was beyond 50 m³/ha. The cost savings were quite small, however, at 0.1–0.7 €/m³

Evaluation of operating cost management models for selection cutting in Scandinavian continuous cover forestry

The importance of continuous cover forestry (CCF) is increasing, yet there is lack of data and understanding about many aspects of this management, including the operational costs. Our objectives were to retrieve available harvesting cost models from published studies on selection cutting in Norway-spruce-dominated stands in Scandinavian countries and to evaluate them against real case studies. First, we retrieved three recently published harvesting cost models which provided explicit cost functions. Models 1 and 2, based on rotation forestry (RF) data and adapted for CCF, had separate sub-models for cutting and hauling costs. Model 3 was based on CCF data and produced total harvesting costs, including the cutting and hauling costs combined. Second, we measured cutting costs for 29 harvesting operations on stands with different stages of CCF structure. We then compared the observations with the simulations of Models 1 and 2 cutting cost sub-models for those cases. Third, we expanded the dataset, including a further 34 harvesting operations in stands with more advanced CCF structures (without measured costs). We then simulated the total harvesting costs for all three models in this dataset to investigate their general behaviour. On average, Models 1 and 2 cutting cost sub-models had relatively good and consistent predictions compared with the observed values. However, they differed in total costs due to different estimates for the hauling cost sub-models. Model 3 had predictions comparable to Models 1 and 2 in the more advanced stages of CCF, but much higher in the less advanced. This study provides important data regarding cutting costs in CCF and demonstrates the feasibility of using existing harvesting cost models

Luonnonvaratiedon hyödyntäminen politiikan ja päätöksenteon tukena : Aineistot, tiedontuotanto, tiedon löydettävyys ja yhteinen palvelumalli

Esiselvitys kuuluu sektoritutkimuksen neuvottelukunnan tutkimusagendojen kestävän kehityksen aihepiiriin teemalla ‘Luonnonvaratiedon hyödyntäminen politiikan ja päätöksenteon tukena’. Esiselvityksen toteutti Geologian tutkimuskeskuksen (GTK) johtama konsortio, johon kuuluivat GTK:n ohella Metsäntutkimuslaitos (Metla), Geodeettinen laitos (GL), Tieteen tietotekniikan keskus (CSC) ja Maanmittauslaitos (MML). Esiselvitys toteutettiin osallistavina ja laajaa sektorien välistä yhteistyötä edistävinä työpajoina, kyselyinä sekä olemassa olevaa ja hankkeessa tuotettua aineistoa analysoimalla. Tämä raportti tuotettiin esiselvitysprojektin osatehtävien tuottamista väliraporteista ja muusta kootusta projektiaineistosta. Tiiviin yhteistyön tuloksena Suomen ympäristökeskuksen (SYKE) johtaman toisen luonnonvaraesiselvityskonsortion kanssa syntyi konsortioiden yhteinen tutkimusohjelmaehdotus. Tämä raportti täydentää tutkimusohjelmaehdotusta ja kokoaa yhteen GTK-konsortion osatehtävien tulokset, niihin perustuvat kehittämisehdotukset, analyysin ja alustavat ehdotukset koskien tarvittavia uusia kehittämishanke- ja tutkimushankekokonaisuuksia eri hallinnonalojen luonnonvaratutkimuksen tietoinfrastruktuurien kehittämiseksi ja luonnonvaratiedon poliittisen hyödynnettävyyden parantamiseksi. Tämä raportti muodostaa luonnonvara-aineistot tuntevien asiantuntijoiden laatiman kokonaisselvityksen luonnonvaroja koskevista tietoaineistoista, tiedon tuotannosta ja tiedon käytettävyydestä. Hankkeen tuloksia hyödynnetään mm. Sitran käynnistämässä kansallisen luonnonvarastrategian laadintaprosessissa, jonka lähtökohtia huomioitiin esiselvityksen painotuksia laadittaessa. Sektoritutkimuslaitosten yhtenä tehtävänä on ylläpitää ja kehittää alansa pitkäaikaista, ohjelmallista tiedonkeruuta ja vastata alan tietopalvelusta. Näiden sektorikohtaisten tehtävien jatkuvuus on turvattava myös tulevaisuudessa. Toisaalta tiedontuottajien tulee kehittää sektorirajat ylittäviä tiedontuotannon sisältöjä ja menetelmiä yhteistyönä. Myös ohjelmallista perustiedonkeruuta (seurantaohjelmat, kartoitusohjelmat) kehitetään sisällöllisesti parhaiten luonnonvarojen hyödyntämisen ja hyödyntämisen vaikutusten samanaikaisissa tarkasteluissa. Eri organisaatioille hajautetun tiedonkeruun järjestämisessä voidaan soveltaa ja kehittää informaatioteknologiaa siten, että tutkijat ja luonnonvarojen hyödyntäjät tuottavat laadullisesti korkeatasoista ja valvottua tietoa hajautettuihin, keskitetysti ylläpidettäviin ja yhteisesti käytettäviin tietokantoihin. Esiselvityksen jälkeen koko sektoritutkimuksen luonnonvarayhteisön yhteisten työmuotojen luominen ja vakiinnuttaminen on erityisen tärkeää, jotta tunnistettujen kehittämiskohteiden vaatimat toimet saadaan käyntiin tarkoituksenmukaisesti. Luonnonvaratietojen palvelumallin toteuttaminen tulee aloittaa laaja-alaisena yhteistyönä, parasta osaamista ja teknologiaa yhdistäen sekä käynnissä olevat kansalliset ja EU:n tutkimus- ja kehittämisprosessit täysimääräisesti hyödyntäen

Quality and productivity in comminution of small-diameter tree bundles

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