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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Eglės (Picea Abies L.) stiebų sortimentinės struktūros dėsningumų tyrimas / Norway spruce (Picea Abies L.) steams simulation structure of the assortment consistent patterns research

Baikauskas, Dainius 16 June 2006 (has links)
Study object – Spruce wood the time is ripe fact – finding in Trakai state forest enterprise, Trakai and Semeliskes forestry stalls. Study aim – Research spruce round wood data kind’s variation consistent pattern and make spruce steams sort models of structure. To reveal basic Lithuanian forest market’s development tendencies, determine main factors, characterizing dynamics of round wood kinds. Study methods – In tests on several groups of Norway spruce (Picea abies (L.) Karst.) comprising more than 309 trees in total, the method detected dynamics of round wood kinds have been evaluated of method correlation analysis with high accuracy. We validated the method both by measurements and by finite element modeling and simulations. Study results – It has been analyzed Norway spruce’s round wood structure models of Trakai state forest enterprise during 2003 – 2005 years. It has been estimated each round wood kind’s simulation with tabulation and evaluated kind of round wood for diameter fluctuation.
2

Lietuvos beržynų sortimentinės struktūros modeliavimas / Assortment structure modeling of birch grove of Lithuania

Vaičius, Dainius 25 June 2006 (has links)
Aim of the work – to analyze the regularities of quality rates variation and to make the evaluation models of birch assortment structure, concerted with Europe Union standard’s requirements. Object of the work – semi mature and mature birch forests. During research there were used measurement data of birch stems quality rates (diameter, bark thickness at full stem length) and round wood defects. Methodology of the research – there were measured pruned birch stems, filled in the model wood card, indicating the forest and the model wood characteristics. After this empirical database was structured and normatives were made, which allow to evaluate the volume of timbers of various diameter and high trees A, B, C and D quality classes, paper wood, firewood and waste wood. Results of the research – birch - grove felling sorting – grading structure prognosis method was prepared. Sorting – grading tables in MS “Excel” computer program make its essence.
3

Vėjavartų medienos kokybės vertinimas Dubravos eksperimentinėje mokomojoje miškų urėdijoje / Evaluation of windblown timber quality in Dubrava forest enterprise

Pupelis, Tomas 01 June 2011 (has links)
Magistro darbe tiriama 2010 m. rugpjūčio mėnesį Dubravos EMMU audros pažeisti medynai ir juose pagaminta apvaliosios medienos kokybė. Darbo objektas – 2010 m. rugpjūčio mėnesį škvalo Dubravos EMMU pažeisti medynai. Medienos kokybės bei medžių stiebų sortimentinės struktūros tyrimai atliekami Dubravos EMMU, Vaišvydavos girininkijoje esančiame škvalo pažeistame brandžiame eglyne. Darbo tikslas – Įvertinti vėjavartų apimtį ir medienos kokybės pokyčius Dubravos EMMU. Darbo metodai – Darbe naudoti dokumentų analizės, duomenų grupavimo, palyginimo, vidurkių skaičiavimo ir apibendrinimo metodai. Darbo rezultatai. Išanalizavus Dubravos EMMU audros likvidavimo metu 2010 m. 10-12 mėn. pagamintų pjautinųjų sortimentų kiekius nustatėme, kad pagaminta 76% daugiau negu visada, prastesnės C klasės medienos. Dubravos EMMU, Šilėnų ir Vaišvydavos girininkijose įvertinus vėjo pažeidimus pagal plotą skirtingose augavietėse 60 brandžių medynų, nustatėme, kad intensyviausiai pažeisti medynai, kurie sudaro 35% yra Lcp augavietėse. Įvertinus pažeistus medynus pagal vyraujančią medžių rūšį nustatyta, kad didžiausią pažeistų medynų dalį 46.9% sudaro eglynai. Sortimentuojant 26 vėjo pažeistus medžius nustatyta, kad dėl pakitusios sortimentinės struktūros dėl lūžių taškuose suskeldėjusios medienos, prarandama iš viso 19.8% likvidinės medienos, bei vidutiniškai vieno medžio kirtimo atliekų kiekis padidėja 2.1 karto. Iš vėjo pažeistų medžių, pjautinųjų sortimentų medienos kokybė lyginant su galimai... [toliau žr. visą tekstą] / Study object – 2010.08.08 storm damaged forest stand at Dubrava forest enterprise. Windblown timber quality assessment and storm damaged tree round wood structure assessment was done at Vaišvydava local forest district, at Dubrava forest enterprise. Study aim - to quantify most damaged forest types and to assess the round wood quality losses due to stem breakage and other defects which reduced merchantable timber volume during logging at damaged stands, after 2010.08.08 storm at Dubrava forest enterprise. Methodology – Data grouping, comparison, generalization, document’s analysis. Results - As the main changes in round wood quality during the period of salvage clear cuttings of storm damaged timber at Norway spruce stands at DFE were seen a significant increase of C quality class Norway spruce (Picea abies L) sawn logs – 76 per cent of all sawn logs. Evaluation of windthrow damage on DFE results showed that nearly half (46.9 percent) of all damages occurred on Norway spruce stands. As the most endangered forest soil type of spruce stands, where one third of all damages occurred, was recorded: fertile and humid Myrtillo-oxalidosum site. Survey of 26 storm damaged trees round wood structure showed, that 19.8% reduction of merchantable volume is due to breakage, and due to that fact was seen significant increase - 2.1 time amount of residuals. Windblown tree round wood quality assessment showed significant difference in timber quality if we compare it with normal conditions... [to full text]
4

Pagrindinių kirtimų sortimentinės struktūros ir pajamų prognozavimo galimybių tyrimai / Research on prognosis of assortment composition and income from final cut

Radzevičius, Sigitas 16 June 2006 (has links)
Amounts of pine sawlogs, pine pulpwood as well as spruce pulpwod can be estimated rather precisely. The accuracy of the prognosis is as high as 90%. The amount of spruce sawlogs can be prognosed with less accuracy (75%). The biggest errors are obtained by prognosis of smal dimensions softwood and hardwood as well as of birch pulpwood. Prognosis of birch pulpwood differs from actuall volume 3.7 times. When prognosed income is being compared with the actual one, very small discrepancies are found, though the assorment composition is different. The difference between actual and theoretical income were 2.4% and -0.5% respectively for 2004 and 2005.

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