Kasetüvede järkamistulemi võrdlus erinevate optimeerimisviiside korral
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Kuupäev
2015
Kättesaadavus
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Abstrakt
Kasest järgatava metsamaterjali ülestöötamine ja kasutamine on võrreldes teiste Eestis
majandatavate põhipuuliikidega võimalusterohke ja samas ka keerulisem. Kuna kase tüvedest
järgatakse hinnalt suure diferentsiga sortimente (paberipuidust spoonipakuni) on optimaalse
järkamislahendiga võimalik rahaliselt palju võita.
Raietulemuse optimaalsuse näitajatena on tavapäraselt mahuline ja rahaline väljatulek.
Uurimuse eesmärgiks on võrrelda järkamistulemust käsitsi ja harvesteriga raiumisel.
Võrreldavuse saavutamiseks kasutati võrdluses samasid 21 valitud kase tüve. Praktiliselt
järkas tüved harvester ja võrdluses olnud kaks käsitsi optimeerimist tehti teoreetiliselt.
Eelkõike oli analüüsimisel tüvest saadavate likviidsete puidusortimentidega tüve ära
kasutamine, mis sõltub tehnilistest võimalustest ja optimeerimislahendist.
Saadud järkamistulemustele avaldab kindlasti mõju mõõtmiste tehniline teostus, millest
tuleneva veaga peab ka antud uurimustöö põhiteema järeldustes arvestama.
Uurimustöö objekt paikneb riigimetsas ja järkamistulemi võrdlus ning harvestermõõtmine
tehti koostöös Riigimetsa Majandamise Keskuse Jõgevamaa metskonnaga. RMK pakkus
puistu, milles oli kavandatud harvesteriga uuendusraie ja andis loa monitooringuks.
Eraldusel uuritavad puud valiti selliselt, et nende eelnev langetamine ja hilisem harvesteriga
järkamine toimuks kompaktselt. Langetamise ja eelmõõtmise töö tuli teha kiiresti. Seetõttu ei
jõutud käsitsi tüvede hindamisel teha koore mõõtmisi. Selgus, et kase koore paksuse suure
diferentsi tõttu võib arvestuslik ja tegelik diameeter erineda. Harvesteri järkamise ajal teostati
valikuliselt erineva diameetriga nottide mõõtmine ja saadi eeldatav keskmine koorepaksuste
jagunemine tüve pikkuses.
Tulemustes selgus, et teoreetilise optimeerimisega sai uurimuseks kasutatud tüvedest
mahuliselt rohkem puitu kui harvesteriga optimeerimisel. Mahulise erinevuse põhjustas
mõõtmiste erinevad lähteülesanded ja harvesteri tehniline suutmatus järgata latvadest
madalama klassiga sortimente. Lisaks oli harvesteril raske järgata harulisi tüvesid.
Kuigi harvesteriga järkamisel saadi väiksem mahuline tulemus, siis järgatud materjali
keskmine tihumeetri hind oluliselt väiksem ei tulnud, sest kallimate sortimentide suurem
osakaal tasandas hinnas olevaid erisusi.
Tüvest saadud rahalise vääringu erinevused põhjustas järkamistulemuste mahuline erinevus ja
optimeerimine. Kolmandaks optimeerimisvõimaluseks kasutatud kitsendatud raiejuhendiga
saadi küll suurim mahuline tulemus, aga tüvedest saadud kogu hind ja keskmine tm hind oli
madalaim, sest kallimaid sortimente ei järgatud.
There is wide range of roundwood assortments (different quality and lenght) for birch’s roundwood in the market in comparison to the other tree species. The wide selection of options makes the stem sectioning to assortments at the same time more complicated. As the price of stemwood monetary value depends on a sectioning of birch stems to the different assortments, the financial gain depends on the price optimal stem sectioning. Stem sectioning optimality indicators are maximised stemwood and monetary outcome. The study’s aim is to compare stem sectioning in case of manual and harvester sectioning. For comparison 21 birch stems from the same stand were selected. Practical sectioning was made by harvester, which was compared with the two theoretical manual optimization. The analysis is based on the comparison of optimization of stem assortments, which depends on the technical possibilities, assortment prices and assortment selection principles. The the stady area is located in the state forest and the study was carried out in collaboration with the Jõgeva county’s forest district of the State Forest Management Centre. RMK (SFMC) offered a stand, which had been scheduled for final felling with the harvester and granted the permission to study. Tree group was selected following the principle, that the felling and the pre measurements had to be done togeter with sectioning.. This is also the reason, that when the manual evaluation of the stems was made, the bark measurements were not. It turned out that the birch bark thickness may differ from actual and imputed due to the large differences in tree diameter along the stem. During the harvester’s cross-cutting, the measurement of different log diameters were executed and the estimated average cortical thicknesses of stem lenght were obtained. The results showed that with the theoretical optimization of the stems used in this study, there was more timber gained than with the harvester optimization. The volume difference was caused by the measurements different approaches and the harvester’s technical incapacity to shear the lower class assortments from the stem. In addition it was hard for the harvester to shear branched stems. Although shearing with the harvester, lower capacity outcome was gained, cross-cut material average cubic meter price did not come significantly lower, because of a higher proportion of the more expensive assortments equalized the price differences. The monetary difference from the strain was caused by the stem sectioning capacity difference and opimization. With the constrained cutting guide, used as the third optimization option, the largest gaine in wolume was obtained, however, the strain derived from the total price and the average cubic meter price were lower, because lower share on more expensice assortments.
There is wide range of roundwood assortments (different quality and lenght) for birch’s roundwood in the market in comparison to the other tree species. The wide selection of options makes the stem sectioning to assortments at the same time more complicated. As the price of stemwood monetary value depends on a sectioning of birch stems to the different assortments, the financial gain depends on the price optimal stem sectioning. Stem sectioning optimality indicators are maximised stemwood and monetary outcome. The study’s aim is to compare stem sectioning in case of manual and harvester sectioning. For comparison 21 birch stems from the same stand were selected. Practical sectioning was made by harvester, which was compared with the two theoretical manual optimization. The analysis is based on the comparison of optimization of stem assortments, which depends on the technical possibilities, assortment prices and assortment selection principles. The the stady area is located in the state forest and the study was carried out in collaboration with the Jõgeva county’s forest district of the State Forest Management Centre. RMK (SFMC) offered a stand, which had been scheduled for final felling with the harvester and granted the permission to study. Tree group was selected following the principle, that the felling and the pre measurements had to be done togeter with sectioning.. This is also the reason, that when the manual evaluation of the stems was made, the bark measurements were not. It turned out that the birch bark thickness may differ from actual and imputed due to the large differences in tree diameter along the stem. During the harvester’s cross-cutting, the measurement of different log diameters were executed and the estimated average cortical thicknesses of stem lenght were obtained. The results showed that with the theoretical optimization of the stems used in this study, there was more timber gained than with the harvester optimization. The volume difference was caused by the measurements different approaches and the harvester’s technical incapacity to shear the lower class assortments from the stem. In addition it was hard for the harvester to shear branched stems. Although shearing with the harvester, lower capacity outcome was gained, cross-cut material average cubic meter price did not come significantly lower, because of a higher proportion of the more expensive assortments equalized the price differences. The monetary difference from the strain was caused by the stem sectioning capacity difference and opimization. With the constrained cutting guide, used as the third optimization option, the largest gaine in wolume was obtained, however, the strain derived from the total price and the average cubic meter price were lower, because lower share on more expensice assortments.
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