Properties of biomass obtained from short-rotation inger willow clone grown on a contaminated and non-contaminated land

The paper aims to analyze the biomass at one year growth, resulting from the cultivation of the INGER energy willow clone as a short rotation crop (SRC), in order to use it as a renewable fuel. The paper completes the data in the field of renewable energies in the context of decreasing fossil energy reserves worldwide and emphasizing the impact on renewable energies. The effect of a contaminated land on the survival rate of the planted seedlings and the effect of the energy willow culture on the composition of the contaminated soil are analyzed. The obtained results show that the biomass characteristics, such as the calorific power of about 18,21 kJ/g to18,90 kJ/g, and the ash content of about 2,25 %, are comparable with the ones of other lignocellulosic energy materials. The results found in this studyshowed that the woody biomass in the first vegetation year of energy willow can be used directly as a renewable fuel without the need for compaction in the form of briquettes or pellets

Reliability Estimation of Towed Grader Attachment Using Finite Element Analysis and Point Estimation

The paper presents an analysis of the reliability of front blade, rear blade and frame of the towed grader as well as experimental validation of the results obtained from the finite element analysis. The analyzed prototype was designed for maintenance and repair of forest roads and equipped with two types of blades for cleaning and levelling the ground surface. Lifetimes of towed grader attachments can be estimated with high accuracy using three-parameter Weibull distribution. The values of the location parameter γ were determined by using the maximum values of the correlation coefficient, while the method of maximum likelihood was used for the point estimation of the parameters. Because higher values of the shape parameter had been obtained, the point estimation and estimation with confidence intervals of components lifetimes were performed. The analysis of the results indicates that the used assumptions may not fully take the complex stresses encountered in use into account

PRIMJENA RAZLIČITIH METODA PODRŽANIH GIS-OM PRI ODREĐIVANJU SREDNJE UDALJENOSTI PRIVLAČENJA DRVA I PRIPADAJUĆIH FAKTORA KOREKCIJE U PLANINSKIM ŠUMAMA RUMUNJSKE

Extraction distance is an important factor used for locating new forest roads. Correction factors should be used for adapting theoretical models to real life situations. The aim of this study was to show how extraction distance and the correction factors can be computed and used for assessing forest road options in a more efficient and effective mann­er using process automation in GIS. The study was located in a mountain forest in the South Central Carpathians of Romania. For determining the mean extraction distance, 71.5 km of skid trails were tracked in the field and mapped in GIS. Four computing methods were defined: raster method, grid point method, buffer strips method and centre of gravity method. For testing and validating the methods, four infrastructure scenarios were defined: one was describing the existing forest infrastructure and three others were proposing new road options. Statistical analyses were performed for testing the accuracy and the possible differences between methods. The paired samples t-tests revealed significant differences between scenarios proposing new forest roads and the current infrastructure conditions. The raster method, the grid point method and the buffer strip method reported high accuracy for computing the mean extraction distance. This study reported an extraction correction factor (ks) value of 1.50 and a total correction factor (kt) value of 3.40 which can be used for rough calculations in practice. The automation models developed in GIS improved the efficiency of computations. The correction factors determined in this study were comparable with those reported in literature, highlighting the reliability of the analysed methods.U Rumunjskoj se, zbog loše razvijene mreže primarne šumske prometne infrastrukture (šumskih cesta i onih javnih cesta, pretežno nižih kategorija, koje se mogu koristiti pri radovima u šumarstvu), u fazi privlačenja drva najčešće koriste skideri. Zbog male je gustoće primarnih šumskih prometnica primjena forvrdera za privlačenje drva izvoženjem, odnosno šumskih žičara za privlačenje drva iznošenjem, vrlo rijetka. Smanjiva­njem udaljenosti privlačenja drva, što je jedna od važnijih zadaća novo planiranih, projektiranih i izgrađenih šumskih cesta, smanjuju se i troškovi privlačenja drva.Stoga je srednja udaljenost privlačenja drva jedan od temeljnih parametar procjene kvalitete i kvantitete postojeće mreže primarnih šumskih prometnica ali i parametar koji se koristi pri daljnjem razvoju i optimizaciji primarnog šumskog transportnog sustava, odnosno na osnovu kojega se, uz ostale dodatne kriterije (pa­rametre), obavlja odabir između više inačica primarnog otvaranja šuma (mreže šumskih cesta) ili pojedinih idejnih trasa šumskih cesta te odabiru najbolje.Srednja se udaljenost privlačenja drva može odrediti različitim metodama rada, a u novije se vrijeme velika većina suvremenih metoda bazira na primjeni GIS tehnologija. Dietz i dr. (1984.) daju najčešće korištene definicije srednje udaljenosti privlačenja drva i definiraju tri inačice srednje udaljenosti privlačenja drva: teorijsku, geometrijsku i stvarnu udaljenost privlačenja drva, te sveukupni korekcijski faktor, koji u sebi obje­dinjuje mrežni korekcijski faktor i korekcijski faktor privlačenja drva (prethodno definirane po Segebaden-u (1964.)), a služi za izravnu pretvorbu teorijske u stvarnu srednju udaljenost privlačenja drva.Osnovni je cilj istraživanja dokazati kako se parametar srednje udaljenosti privlačenja, uz primjenu suvremenih tehnologija rada (GIS) te poznatih i novo razvijenih metoda i postupaka, ali i uz automatizaciju komple­tnog postupka, može vrlo učinkovito koristiti pri ocjeni različitih inačica unapređenja postojeće mreže primarnih šumskih prometnica u postupku njene optimizacije, te pri određivanju prije navedenih korekcijskih faktora srednje udaljenosti privlačenja drva.Istraživanje je provedeno u rumunjskim privatnim šumama smještenima u jugo-centralnim Karpatima regije Brașov, na površini od 903 ha. Radi se o bukovim planinskim šumama srednjega boniteta na plitkome tlu i nagnutim terenima. Godišnji je etat oko 4310 m3, a privlačenje drva se obavlja skiderima i adaptiranim poljoprivrednim traktorima. Oko 20 % površine istraživanog područja ima blagi nagib terena (<20%), a oko 10 % se nalazi na vrlo strmom terenu (>55%). Mreža stalnih vodotoka je vrlo razvijena. Šumska se prometna infrastruktura sastoji od 11,7 km šumskih cesta te 71,5 km traktorskih putova (koji su snimljeni GPS uređajem Garmin 60 CSx GPSMAP te je, uz postojeći katastar primarnih, formiran katastar sekundarnih šumskih ­prometnica).Za određivanje teorijske, geometrijske i stvarne srednje udaljenosti privlačenja su korištene četiri metode rada podržane GIS-om: rasterska metoda, metoda pravilne mreže točaka (sa pet veličina otvora mreže predstavljene inačicama: G10, G50, G100, G500 i G1000, gdje svaki broj iza slova G predstavlja razmak između točaka iskazan u metrima), metoda omeđenih površina i težišna metoda (CGR). Za testiranje, međusobnu usporedbu i ocjenu korištenih metoda izrađena su četiri scenarija optimizacije mreže primarnih šumskih prometnica. Prvi scenarij (Zero) predstavlja postojeće stanje, a ostala tri scenarija (FR1, FR2 i FR3) unapređenje postojeće primarne šumske prometne infrastrukture sa ciljem njihove optimizacije. Uz srednju udaljenost privlačenja drva, za svaki su scenarij određene najveća i najmanja udaljenost privlačenja te razmak između šumskih cesta. Automatizacija postupka izračuna je izrađena u aplikaciji Model Builder™ (ESRI® ArcGIS) uz uporabu digitalnog modela terena (DTM). Alat „Batch processing“ iz aplikacije Model Builder™ je korišten za odabir većeg broja ulaznih datoteka i kreiranja višestrukih rezultata. Provedena je statistička analiza između četiri metode rada korištene pri određivanju parametra srednje udaljenosti privlačenja drva. T-test parova ukazuje na statistički značajnu razliku između triju predloženih inačica optimizacije primarnog šumskog transportnog sustava i postojećeg stanja primarne šumske prometne infrastrukture. Rasterska metoda, metoda pravilne mreže točaka i metoda omeđenih površina su visoko točne metode za određivanje srednje udaljenosti privlačenja drva. Inačice metode pravilne mreže točaka G100, G50 i G10 su najtočnije metode za izračun korekcijskog faktora privlačenja drva (ks) (koji se koristi pri pretvorbi geometrijske u stvarnu srednju udaljenost privlačenja drva). Metoda pravilne mreže točaka G100 se preporuča za operativnu primjenu u šumskim kompleksima od oko 1000 ha i većima. Rasterska se metoda izračuna sugerira za određivanje stvarne inačice srednje udaljenosti privlačenja drva (SDe). Na istraživanom je području određena vrijednost korekcijskog faktora privlačenja drva u rasponu od 1,13 do 1,79, sa srednjom vrijednošću od 1,50 koja se predlaže za uporabu u operativnom šumarstvu. Mrežni korekcijski faktor istraživanog područja (kn) poprima vrijednosti u intervalu 1,65 – 2,15, uz pretpostavku da se scenarijima unapređenja postojeće mreže primarnih šumskih prometnica planiraju šumske ceste koje će čitavom svojom duljinom šumu otvarati obostrano. Sveukupni korekcijski faktor (kt) na području istraživanja poprima vrijednosti između 3,02 i 3,85, a šumari u praktičnom šumarstvu se upućuju na vrijednost od 3,40.Automatizirani model razvijen u GIS-u, a korišten pri izračunu srednje udaljenosti privlačenja drva, pripadajućih korekcijskih faktora i različitih inačica unapređenja postojeće mreže primarnih šumskih prometnica, doprinosi povećanju učinkovitost i točnosti dosadašnjih izračuna navedenih parametara. Vrijednosti korekcijskih faktora srednje udaljenosti privlačenja drva su vrlo slične literaturnim vrijednostima korekcijskih faktora dobivenim dosadašnjim istraživanjima u usporedivim reljefnim područjima. To ukazuje na moguću i preporučljivu primjenjivost rezultata istraživanja u operativnome šumarstvu

Comparative Studies on Two Types of OSB Boards Obtained from Mixed Resinous and Fast-growing Hard Wood

The paper aims to compare the oriented strand boards (OSBs) made in the laboratory from a mixture of softwood species to those made from hardwood species, followed by their comparison to European and industry standards. In this regard, the main properties of the panels made in the laboratory were determined, including density, absorption, and swelling in thickness, modulus of elasticity, modulus of rupture, and internal bond. The analysis of the properties of swelling (24 h) and absorption (24 h) revealed that the mixture of softwood species was slightly better thanthe hardwood one. It was also shown that the panels manufactured from the mixture of hardwood species had better mechanical properties than those made of the softwood mixture (modulus of rupture (MOR) = 43.48 N/mm2, modulus of elasticity (MOE) = 7253 N/mm, and internal bond (IB) = 1.57 N/mm2). Additionally, the comparative analysis of properties indicates that the density is highly significant in determining the MOE values of the OSBs. This will allow softwood speciestobe replaced with other species of soft and fast-growing deciduous trees such as willow, birch, and poplar in the manufacture of oriented strand boards

Reliability analysis of scarifying tooth for trailed scarifier

In this paper are estimated the reliability indicators of scarifying tooth for trailed scarifier. Taking into account the constructive and technological factors, as well as the duration of exploitation, the determined values of Anderson-Darling statistics indicates that the Weibull distribution permits to model with maximum accuracy the lifetime of such attachment. The location parameter is estimated using the correlation coefficient method and minimum lifetimes are determined experimentally. Analyzing the obtained parameters, it can be shown that it can be used the normal distribution for reliability estimation. In this respects, it was applied the point and confidence interval estimation of the average and standard deviation lifetime of scarifying teeth of trailed scarifier

An Integrative Decision Support Tool for Assessing Forest Road Options in a Mountainous Region in Romania

Sound development of forest infrastructure represents the backbone for sustainable forest management. However, planning forest roads, which nowadays must fulfill multiple conflicting objectives, is not an easy task. A GIS based model was developed for supporting decision making in forest road engineering. The tool allowed assessment of forest infrastructure scenarios based on multiple criteria analyses, considering stakeholders’ interests, economic, ecological and social aspects. First, the decision problem was clearly structured and then criteria and sub-criteria were weighted. Then, forest road scenarios were defined and quantitative and qualitative assessments regarding infrastructure and harvesting systems were performed. In the end, utility analysis for each scenario was conducted, the forest road variant with the highest utility score being selected as the most suitable option for implementation. The model was tested and validated in a mountain forest area from Brasov County, Romania. Reduction of mean skidding distance from 864 m to 255–268 m was reported, leading to an increase in productivity of timber extraction from 7.5 m3/h to 11.7 m3/h and to an increased contribution margin from 21.2 €/m3 to 25.1 €/m3. Enhancement of forest infrastructure reduced CO emissions re timber harvesting and transport from 8.52 kg/m3 to 7.3 kg/m3. This study showed how multiple attribute utility theory could be used in assessing different forest road options based on a participatory approach

Reliability analysis of scarifying tooth for trailed scarifier

In this paper are estimated the reliability indicators of scarifying tooth for trailed scarifier. Taking into account the constructive and technological factors, as well as the duration of exploitation, the determined values of Anderson-Darling statistics indicates that the Weibull distribution permits to model with maximum accuracy the lifetime of such attachment. The location parameter is estimated using the correlation coefficient method and minimum lifetimes are determined experimentally. Analyzing the obtained parameters, it can be shown that it can be used the normal distribution for reliability estimation. In this respects, it was applied the point and confidence interval estimation of the average and standard deviation lifetime of scarifying teeth of trailed scarifier

Reliability analysis of scarifying tooth for trailed scarifier

In this paper are estimated the reliability indicators of scarifying tooth for trailed scarifier. Taking into account the constructive and technological factors, as well as the duration of exploitation, the determined values of Anderson-Darling statistics indicates that the Weibull distribution permits to model with maximum accuracy the lifetime of such attachment. The location parameter is estimated using the correlation coefficient method and minimum lifetimes are determined experimentally. Analyzing the obtained parameters, it can be shown that it can be used the normal distribution for reliability estimation. In this respects, it was applied the point and confidence interval estimation of the average and standard deviation lifetime of scarifying teeth of trailed scarifier

Influence of the Strand Characteristics on the Properties of Oriented Strand Boards Obtained from Resinous and Broad-Leaved Fast-Growing Species

The paper aims to investigate the influence of the characteristics of the strands on the properties of oriented strand boards (OSB). To solve this objective, some global synthetic characteristics of the strands (the slenderness ratio, the characteristics of thinness, and the specific surface) of four wood species currently used in this technology (spruce and pine for softwood, and poplar and willow for hardwood) were first studied. The characteristics of the OSB obtained from each species separately were also determined, and finally the correlations analysis was made between the characteristics of the strands and those of the corresponding OSB boards. The working methodology used the European tests regarding the physical and mechanical properties of the boards, but also algorithms for forecasting and evaluating the quality of the strands and boards. The conclusions regarding the characteristics of the strands have highlighted the role of the specific surface of the strand and the characteristics of the thickness; respectively, the conclusions regarding the characteristics of the boards showed that the fast-growing species of willow and poplar lead to obtaining higher quality OSB boards. The general conclusion of the paper is that the characteristics of the strands have a significant influence on the physical–mechanical properties of the OSB board