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V prispevku predstavimo podlago za izdelavo usmeritev pri gospodarjenju z navadno smreko v Sloveniji. Izvedli smo več ločenih analiz z istim ciljem: pripraviti strokovno utemeljene in s podatki podprte usmeritve za gospodarjenje z navadno smreko v Sloveniji v prihodnjih desetletjih. Tako smo v tem prispevku združili rezultate meritev nacionalne gozdne inventure, analizo priraščanja smreke, analize vrstne pestrosti ter pregled osnutkov načrtov za gozdnogospodarska območja. Namen tega prispevka je predstavitev rezultatov štirih ločenih sklopov analiz podatkov, ki so predstavljali osnovo za izdelavo usmeritev pri gospodarjenju z navadno smreko, objavljenih v naslednjem prispevku. In our article, we present the foundation for the preparation of the guidelines for Norway spruce management in Slovenia. We performed several separate analyses following the same goal: to prepare professionally founded and data-supported guidelines for Norway spruce management in Slovenia in the future decades. Thus, in this article, we combined the measurement results of the national forest inventory, spruce increment analysis, species diversity analyses, and overview of the drafts of the forest management regions plans. This article aims to present the results of the four separate data analysis complexes representing the foundation for the preparation of the guidelines in the Norway spruce management, published in the next article. Bibliografija: str. 349-350. Izvleček ; Abstract.

Nasl. z nasl. zaslona. Opis vira z dne 13. 12. 2022. Bibliografija: str. 6.

Ov. nasl. Avtorji navedeni v kolofonu.

Ov. nasl. Avtorji navedeni v kolofonu.

Krivulje za opis oblike debla (KOOD) (ang. t.i. »taper functions«) zvezno opisujejo odnos med višino drevesa in premerom debla na ravni posameznega drevesa, od tal do vrha drevesa. Z njihovo uporabo lahko na katerikoli višini od tal (ali od vrha drevesa) določimo premer debla in tako lahko npr. pri izračunih prostornine drevesa ali sortimentov izberemo poljuben zgornji najmanjši premer, izračunamo srednje premere posameznih sortimentov ali izračunamo prostornino posameznih poljubno izbranih delov debla. Kar potrebujemo za izračun prostornin kot vhodni podatek, je drevesna vrsta, prsni premer ter višina (izmerjena ali izračunana iz višinske krivulje) ter KOOD. Na primeru smreke predstaviva prednosti in omejitve omenjenih krivulj ter narediva primerjavo izdelane slovenske KOOD za smreko in obstoječih nemških KOOD. Rezultati določanja prostornine dreves po obeh KOOD so primerljivi. S pomočjo sekcijskih meritev premerov, bodisi ročnih ali optičnih, lahko tuje KOOD lokalno prilagodimo za slovenske razmere. Z uporabo KOOD izboljšamo zanesljivost določanja prostornine dreves in omogočimo nove preračune prostornin potencialnih sortimentov Taper functions continuously describe the relationship between the tree height and the trunk diameter at the level of an individual tree from the ground to the top of the tree. Using them, we can determine the trunk diameter at any height from the ground (or top of the tree) and can, e.g., calculate the volume of the tree or assortment, select an optional upper minimum diameter, calculate median diameters of individual assortments, or calculate the volume of individual optionally selected trunk parts. Tree species, diameter at breast height, height (measured or calculated from the height function), and taper function are the input data we need for calculating the volumes. In the example of spruce, we present the advantages and limitations of the mentioned functions and compare our own taper functions with existing German taper functions. The results of determining tree volume by both taper functions are comparable. Using section measurements of the diameters, manual or optical ones, we can locally adapt foreign taper functions for the Slovenian situation. Using taper functions, we improve the reliability of tree volume determination and enable new calculations of the potential assortments’ volumes.

Environmental conditions affect tree-ring width (TRW), wood structure, and, consequently, wood density, which is one of the main wood quality indicators. Although studies on inter- and intra-annual variability in tree-ring features or density exist, studies demonstrating a clear link between wood structure on a cellular level and its effect on wood density on a macroscopic level are rare. Norway spruce with its simple coniferous structure and European beech, a diffuse-porous angiosperm species were selected to analyze these relationships. Increment cores were collected from both species at four sites in Slovenia. In total, 24 European beech and 17 Norway spruce trees were sampled. In addition, resistance drilling measurements were performed just a few centimeters above the increment core sampling. TRW and quantitative wood anatomy measurements were performed on the collected cores. Resistance drilling density values, tree-ring (TRW, earlywood width–EWW, transition-TWW, and latewood width–LWW) and wood-anatomical features (vessel/tracheid area and diameter, cell density, relative conductive area, and cell wall thickness) were then averaged for the first 7 cm of measurements. We observed significant relationships between tree-ring and wood-anatomical features in both spruce and beech. In spruce, the highest correlation values were found between TRW and LWW. In beech, the highest correlations were observed between TRW and cell density. There were no significant relationships between wood-anatomical features and resistance drilling density in beech. However, in spruce, a significant negative correlation was found between resistance drilling density and tangential tracheid diameter, and a positive correlation between resistance drilling density and both TWW + LWW and LWW. Our findings suggest that resistance drilling measurements can be used to evaluate differences in density within and between species, but they should be improved in resolution to be able to detect changes in wood anatomy. Nasl. z nasl. zaslona. Opis vira z dne 8. 4. 2022. Bibliografija: str. 11-13.

Krivulje za opis oblike debla (KOOD) (ang. t.i. »taper functions«) zvezno opisujejo odnos med višino drevesa in premerom debla na ravni posameznega drevesa, od tal do vrha drevesa. Z njihovo uporabo lahko na katerikoli višini od tal (ali od vrha drevesa) določimo premer debla in tako lahko npr. pri izračunih prostornine drevesa ali sortimentov izberemo poljuben zgornji najmanjši premer, izračunamo srednje premere posameznih sortimentov ali izračunamo prostornino posameznih poljubno izbranih delov debla. Kar potrebujemo za izračun prostornin kot vhodni podatek, je drevesna vrsta, prsni premer ter višina (izmerjena ali izračunana iz višinske krivulje) ter KOOD. Na primeru smreke predstaviva prednosti in omejitve omenjenih krivulj ter narediva primerjavo izdelane slovenske KOOD za smreko in obstoječih nemških KOOD. Rezultati določanja prostornine dreves po obeh KOOD so primerljivi. S pomočjo sekcijskih meritev premerov, bodisi ročnih ali optičnih, lahko tuje KOOD lokalno prilagodimo za slovenske razmere. Z uporabo KOOD izboljšamo zanesljivost določanja prostornine dreves in omogočimo nove preračune prostornin potencialnih sortimentov. Taper functions continuously describe the relationship between the tree height and the trunk diameter at the level of an individual tree from the ground to the top of the tree. Using them, we can determine the trunk diameter at any height from the ground (or top of the tree) and can, e.g., calculate the volume of the tree or assortment, select an optional upper minimum diameter, calculate median diameters of individual assortments, or calculate the volume of individual optionally selected trunk parts. Tree species, diameter at breast height, height (measured or calculated from the height function), and taper function are the input data we need for calculating the volumes. In the example of spruce, we present the advantages and limitations of the mentioned functions and compare our own taper functions with existing German taper functions. The results of determining tree volume by both taper functions are comparable. Using section measurements of the diameters, manual or optical ones, we can locally adapt foreign taper functions for the Slovenian situation. Using taper functions, we improve the reliability of tree volume determination and enable new calculations of the potential assortments’ volumes. Besedilo v slov. Bibliografija: str. 75-76. Izvleček ; Abstract.

V prispevku predstavimo podlago za izdelavo usmeritev pri gospodarjenju z navadno smreko v Sloveniji. Izvedli smo več ločenih analiz z istim ciljem: pripraviti strokovno utemeljene in s podatki podprte usmeritve za gospodarjenje z navadno smreko v Sloveniji v prihodnjih desetletjih. Tako smo v tem prispevku združili rezultate meritev nacionalne gozdne inventure, analizo priraščanja smreke, analize vrstne pestrosti ter pregled osnutkov načrtov za gozdnogospodarska območja. Namen tega prispevka je predstavitev rezultatov štirih ločenih sklopov analiz podatkov, ki so predstavljali osnovo za izdelavo usmeritev pri gospodarjenju z navadno smreko, objavljenih v naslednjem prispevku. In our article, we present the foundation for the preparation of the guidelines for Norway spruce management in Slovenia. We performed several separate analyses following the same goal: to prepare professionally founded and data-supported guidelines for Norway spruce management in Slovenia in the future decades. Thus, in this article, we combined the measurement results of the national forest inventory, spruce increment analysis, species diversity analyses, and overview of the drafts of the forest management regions plans. This article aims to present the results of the four separate data analysis complexes representing the foundation for the preparation of the guidelines in the Norway spruce management, published in the next article.

Spremljanje kakovosti lesa se začne v gozdu, saj je poznavanje trenutnega stanja eden izmed ključnih dejavnikov pri usmerjanju nadaljnjega razvoja gozda v smer večje kakovosti lesne surovine. Usmerjanje razvoja gozdov v smer večje kakovosti in s tem večje dodane vrednosti lesu pa za začetek terja merljivost kakovosti. Brez tega je presoja morebitnih ukrepov v sestoju skoraj nemogoča ali vsaj zelo otežena. Trenutno uporabljena metodologija za ocenjevanje kakovosti stoječih dreves na stalnih vzorčnih ploskvah Zavoda za gozdove Slovenije temelji na neveljavnih žagarskih standardih in bi jo bilo treba posodobiti za splošno uporabo v gozdarstvu. V prispevku je na kratko opisana obstoječa metodologija, predstavljen je pregled obstoječih metodologij ocenjevanja kakovosti stoječih dreves različnih držav in predlagana nova metodologija za ocenjevanje kakovosti dreves. Osnovni cilj opisanega dela je bil razvoj metodologije, s katero bi lahko objektivno primerjali kakovost debel med različnimi sestoji in bi omogočala sortiranje prostornine dreves v potencialne gozdnolesne sortimente (t.i. »sortimentacija«). Uporaba predlagane lestvice kakovosti za opis kakovosti stoječih dreves je lahko eden izmed pripomočkov pri odločanju kam, koliko časa ali sredstev vložiti v gozdnogojitveno ukrepanje v posameznem sestoju. Monitoring of wood quality begins in the forest, since knowing the current status represents one of the key factors in directing further forest development towards higher quality of wood. However, directing forest development towards a higher wood quality and thereby its higher added value demands, to start with, measurability of the quality. Without it, the assessment of the eventual measures in the stand is almost impossible or, at least, very difficult. The currently used methodology for estimating the stem quality of standing trees on the permanent sample plots of the Slovenia Forest Service is based on the invalid sawmill standards and should be updated for general use in forestry. In this article, we briefly describe the existing methodology, present the review of the existing methodologies for estimating the stem quality of standing trees in diverse countries, and suggest a new methodology for estimating the stem quality of the trees. The basic goal of the described work was the development of the methodology with which we could objectively compare the stem quality from different stands, and which would enable assorting these trees' volumes into the potential forest wood assortments. The use of the suggested quality scale for describing the stem quality of the standing trees can represent one of the accessories for deciding where and how much time or assets should be invested in silvicultural measures in an individual stand.

V magistrski nalogi je preučena uporabnost ultrazvoka za zaznavanje notranjih anomalij v stoječih drevesih. V sestoju so bila z ultrazvokom izmerjena drevesa bukve in smreke ter popisane njihove zunanje značilnosti. Na licitaciji vrednejših sortimentov so bili z ultrazvokom izmerjeni sortimenti gorskega javorja z in brez rebraste teksture. Preizkušane so bile hitrosti prehoda v 7 smereh ter 2 ravninah. Oblikovanih je bilo 7 novih spremenljivk, izpeljanih iz frekvenčnega spektra, dobljenega s FFT. Prisotnost trohnobe v smreki in rdečega srca v bukvi statistično značilno vplivajo na hitrosti ultrazvoka in analizirane frekvenčne spremenljivke, v obeh primerih prisotnost anomalije zmanjša hitrost ultrazvoka. Verjetnost rdečega srca se povečuje s prsnim premerom in večvrhatostjo. Hitrosti ultrazvoka so neuporabne za napovedovanje rdečega srca v bukvi, vključitev frekvenčnih spremenljivk v binarno logistično regresijo izboljša pravilnost napovedovanja (iz 80 % na 81,8 %). Prisotnost poškodb oboda in zniževanje hitrosti v tangecialnih smereh zmanjša verjetnost prisotnosti trohnobe pri smreki, model pravilno uvrsti 88,5 % analiziranih dreves. Model smo izboljšali z vključitvijo frekvenčnih spremenljivk na 91,5 %. Postopek meritev v sestoju, ki smo ga pohitrili z izključitvijo hitrosti iz modela, pravilno uvršča 87,3 % analiziranih smrek. Med sortimenti gorskega javorja z in brez rebraste teksture so bile odkrite statistično značilne razlike v hitrosti ene izmed smeri in pri več frekvenčnih spremenljivkah. In this master thesis the use of ultrasound on standing trees to detect inner anomalies has been studied. Standing trees of beech and Norway spruce were measured with ultrasound in forest stands, outer characteristics of trees were also recorded. Logs of sycamore maple with and without fiddleback figure were also measured using ultrasound. 7 measuring directions were tested in two planes. 7 new variables were created using frequency spectrum. Presence of rot in spruce and of red heart in beech significantly impact speed of sound and the frequency spectrum. Presence of anomalies lowered ultrasound velocity in both species. Probability of red heart presence increases with breast height diameter and number increased with tree forking. Speed of ultrasound is not usable in predicting presence of red heart in beech. Frequency spectrum variables contribute to predicting red heart presence, as model accuracy improves after including them from 80 % to 81,8 %. Presence of previously inflicted injuries and low speeds of sound in tangential plane increases probability of rot presence in spruce, the developed model accurately classifies 88,5 % cases. To speed up the measurement process speeds of ultrasound were excluded from the model, the new model is accurate in 87,3 % cases. Statistically significant differences were found in speed of sound in tangential wood direction and in some of the frequency spectrum variables between sycamore maples with or without fiddleback figure.

V prispevku predstavljamo proces in rezultate določitve korekcijskih količnikov za pretvorbo rezistografskih gostot, izmerjenih na stoječih drevesih, v osnovno gostoto lesa na primeru bukve (Fagus sylvatica L.), puhastega hrasta (Quercus pubescens Willd.) in črnega bora (Pinus nigraArnold.). Korekcijski količniki so bili določeni na podlagi sveže odžaganih kolutov, ki so bili povrtani z rezistografom. Kolute smo stehtali, izmerili njihovo prostornino ter jih posušili do absolutno suhega stanja. Iz zbranih podatkov smo nato izračunali osnovno gostoto lesa ter korekcijske količnike med osnovno in rezistografsko gostoto. V raziskavo je bilo zajetih 59 kolutov. Aritmetična sredina vseh izmerjenih količnikov znaša 1,41, vrednosti 95 % intervala zaupanja pa znašajo od 1,38 do 1,46. Razlike med drevesnimi vrstami so statistično neznačilne. Rezistografska gostota relativno dobro odraža osnovno gostoto kolutov (Pearsonov korelacijski koeficient = 0,91 p < 0,001), kar nakazuje na relativno dobro povezanost osnovnih gostot kolutov z rezistografskimi gostotami. Dobljeni rezultati so ključnega pomena za nadaljnji razvoj področja merjenja dejanskih gostot lesa v stoječih drevesih na hiter in relativno nedestruktiven način. In this article, we present the process and results of the determination of correction quotients for conversion of resistograph densities, measured in standing trees, into basic wood densities on the example of beech (Fagus sylvatica L.), pubescent oak (Quercus pubescens Willd.), and black pine (Pinus nigra Arnold.). The correction quotients were defined based on freshly sawn-off stem disks drilled with resistograph. We weighted the stem disks, measured their volume, and dried them to the absolutely dry state. From the gathered data, we then calculated basic wood density and correction quotients between the basic and resistograph density. The research comprised 59 stem disks. The arithmetic mean of all measured quotients amounts to 1.41, and the values of the 95 % of trust intervals amount from 1.38 to 1.46. The differences between the tree species are statistically insignificant. The resistograph density reflects the basic density of the reels (Pearson correlation coefficient = 0,91 p < 0,001) relatively well, which indicates a relatively good connection of the basic densities of the reels with their resistograph densities. The obtained results are crucial for further development of the field of measurement of actual wood densities in standing trees in a fast and relatively non-destructive way

Koncept pametne vasi v strokovni literaturi še ni enotno opredeljen. Večina opredelitev v EU izhaja iz praktičnih primerov: pri pametnih vaseh gre najpogosteje za poskus reševanja določene problematike podeželja (dostopnost zdravstvenih, prehranskih, izobraževalnih storitev, oskrba starejših, digitalno opolnomočenje, povezanost skupnosti ipd.) z uporabo inovativnih digitalno podprtih rešitev. Na podlagi celovitega terenskega dela smo v Krškem gričevju, reliefno razgibanemu podeželskemu območju, ki se sooča z zelo raznoliko prebivalstveno dinamiko, zasnovali tri projektne ideje, ki sledijo konceptu pametne vasi. Prva se nanaša na posodobitev obstoječe kolesarske poti Smednik – Straža pri Raki z e-kolesi, druga na vzpostavitev medgeneracijskega centra na Raki, ki bi lokalnemu prebivalstvu poleg druženja omogočil pridobivanje novega znanja. Tretja ideja vključuje snovanje mobilne aplikacije za lokalne vinogradnike, ki bi jim omogočala izmenjavanje informacij in znanja. Izvedene projektne ideje bi na izbranem območju lahko prispevale k boljši povezanosti prebivalstva, višji stopnji digitalne pismenosti in boljšemu psihosocialnemu stanju ter oblikovanju novih delovnih mest. The concept of a smart village is not yet defined uniformly in the professional literature. Most definitions in the EU are based on practical examples: smart villages are most often an attempt to solve specific rural areas issues (access to health, nutritional, and educational services, care for the elderly, digital empowerment, community networking, etc.) using innovative digitally supported solutions. Based on the comprehensive fieldwork, we designed three project ideas in the Krško Hills, a relief-rich rural area facing very diverse population dynamics. The ideas follow the concept of a smart village. The first refers to the modernization of the existing cycling route Smednik – Straža pri Raki with e-bikes, the second to the establishment of an intergenerational center in rural settlement Raka which would enable the local population to acquire new knowledge in addition to socializing. The third idea includes designing a mobile application for local winegrowers that would allow them to share information and knowledge. The implemented project ideas in the selected area could contribute to a better cooperation within the local community, a higher level of digital literacy, a better psychosocial situation, and the creation of new jobs.

V prispevku je predstavljen primer raziskave o variabilnosti kakovosti lesa različnih drevesnih vrst v slovenskih gozdovih. Meritve gostote, ki je eden glavnih pokazateljev kakovosti lesa, bodo služile za izdelavo podatkovne baze za oceno prostorske variabilnosti kakovosti lesa v Sloveniji. Zanesljivih in objektivnih podatkov o kakovosti lesa v naših gozdovih je relativno malo. Takšne baze so na ravni Slovenije izjemno pomembne, saj omogočajo vpogled v kakovost lesa, ki bo v prihodnje na voljo kot surovina na trgu za domačo lesno industrijo. Podobne baze bodo pomembne za izračun količine vezanega ogljika v nadzemni in podzemni biomasi za Slovenijo, hkrati pa bodo zbrani podatki služili tudi kot izhodišče za nadaljnje analize kakovosti lesa, zlasti mehanske lastnosti, ki so ključne pri uporabi lesa za konstrukcijske namene. Lastnosti in razpoložljivost lesa ekonomsko pomembnih drevesnih vrst so osnova za razvoj gozdno-lesne verige glede novih tehnologij, razvoja novih biomaterialov in potenciala rabe lesa različnih kakovosti z optimalnimi izkoristki. This article presents an example of the research on the variability of wood quality of diverse tree species in Slovenian forests. Measurements of density, which is one of the grade-determining properties of wood quality, will serve for making a database for spatial variability of wood quality in Slovenia. There are relatively few reliable and objective data on wood quality in our forests. Such databases are extremely important on the Slovenian level since they enable insight into the quality of wood which will be available as a raw material for the national wood processing industry on the market in the future. Similar databases will be important for the calculation of the quantity of carbon, locked in the above-ground und under-ground biomass, for Slovenia at the same time, the acquired data will also serve as a starting point for further wood quality analyses, above all its mechanical characteristics which are crucial in the use of wood for construction purposes. Characteristics and availability of wood of economically significant tree species form the basis for the development of the forest-wood chain regarding new technologies, development of new biomaterials, and potential of the use of diverse quality wood with optimal efficiency.

V diplomski nalogi so preučene splošne značilnosti pojava lesa gorskega javorja z rebrasto teksturo (ki je posledica valovitega poteka aksialnih elementov v lesu), vzrokih njenega nastanka, njen razpored znotraj debla ter morebitno geografsko pogojenost pojava dreves s tako teksturo v Sloveniji. Na vsakoletni licitaciji vrednejših sortimentov v Slovenj Gradcu so bili na sortimentih javorja z rebrasto teksturo na obodu sortimentov izmerjeni izraženi znaki rebratosti - širine, višine ter gostote valov. Narejena je bila presoja vpliva različnih dejavnikov na ceno sortimentov javorja z različnimi deleži rebraste teksture. Les z rebrasto teksturo sicer dosega visoko ceno, vendar prisotnost rebraste teksture sama po sebi še ne zagotavlja nadpovprečne cene lesa. Sortimenti z rebrasto teksturo, ki so dosegli podpovprečne in nadpovprečne cene so se med drugim razlikovali po večjem premeru, daljši dolžini in večji absolutni dolžini lesa z rebrasto teksturo. Na podlagi rezultatov raziskave ugotavljajo, da bi bilo smiselno podrobneje raziskati vpliv genetskih dejavnikov na pogostost in razpored rebraste teksture. Tako bi lahko bolje razumeli odnose med dejavniki, ki vplivajo na ceno ter dosegli maksimalen donos, upoštevajoč tudi pravočasni posek lesa. Na podlagi izdelanih geografskih kart relativnih gostot javorja sklepajo, da se drevesa z rebrasto teksturo enakomerno pojavljajo med drevesi brez nje in da pojav rebraste teksture ni geografsko omejen. In this graduation thesis general characteristics of the phenomenon of sycamore wood with fiddleback figure (also known as curly maple with wavy grain) have been explored, figure distribution within wood assortments and the potential geographic distribution of such wood with fiddleback figure in Slovenia. Impact of various factors (waves height, width and density) on the price of assortments on annual lumber auction in Slovenj Gradec has been assesed. Fiddleback figure in sycamore wood does not guarantee above-average price of wood. Based on results we also concluded that it would be reasonable to investigate the impact of genetic factors on auction achieved price to improve understanding of complex relationships between price influencing factors to achieve maximum value of sycamore wood with fiddleback texture, of course taking into account harvesting such assortments in time. Based on in ArcGis drawn maps of relative densities of the geographical origin of lumber assortments with or without fiddleback figure we concluded that trees with fiddleback figure are evenly distributed among sycamore trees without such figure. Results indicate that fiddleback figure in sycamore wood is not just alocalized phenomenon in Slovenia.

The increase in the use of structural timber in construction over recent years has been one of the main drivers behind the renewed interest in optimizing forest management for timber quality. Past research and forest management have been more focused on producing larger quantities of timber in a shorter amount of time, while the relationship between forest management and timber quality is not well understood. A better understanding of that relationship is needed in order to successfully manipulate the quality of the timber produced, especially in fast growing species currently planted and grown in Ireland and elsewhere in Europe. This research study examined the relationships between tree characteristics, forest management and timber quality in three softwood species, grown in Ireland. A relatively large-scale study was performed, using trees from six different stands of Douglas fir, Norway spruce and Sitka spruce. Half of the stands was regularly managed with thinning and the other half was not managed. A total of 600 standing trees of different species was included, and their crown and stem properties were assessed. Acoustic velocity was measured in all trees of the three main softwood species, after which the trees were felled and a sub-sample of them sawn into structural-sized timber. Over 1300 structural-sized boards were assessed non-destructively and tested destructively in four-point bending. Small clear specimens were extracted as close to the fracture as possible, evaluated non-destructively and tested in three-point bending. The data were analysed using a novel, multi-level approach using Bayesian data analysis. The analysis was conducted on the full sample of standing trees using acoustic velocity, on the sub-sample of trees cut into structural-sized boards using mechanical properties and on small clear specimens using mechanical properties. This innovative approach enabled a comparison of the analyzed relationships across three different measurement levels instead of only using one, as commonly done by past studies. The results indicate that thinning negatively affects mechanical properties overall, with the size of the loss dependent on the species. In Sitka spruce, the loss was negligible and thinning was recommended for maximizing volume production with a negligible loss in mechanical properties. Tree characteristics were shown to have a significant impact on the mechanical properties of the timber. Crown social class was found to have an effect, as did crown projection area and stem slenderness. Several other measured variables (crown ratio, crown eccentricity or crown roundness) were found to have no influence on mechanical properties. This study also examined the use of acoustic velocity in standing trees for prediction of timber quality. The results indicate that acoustic velocity cannot be used reliably in larger-diameter trees for prediction of the mechanical properties of timber. While this appears to be possible in smaller-diameter trees, alternative methods of evaluating timber of standing trees are needed to achieve the same in trees of larger diameters. This study also examined the relationships between mechanical properties of boards and small clear specimens cut from those boards. Overall, the relationships were poor-to-moderate. However, this study has successfully demonstrated that in order to evaluate mechanical properties on the level of an individual tree, either specimen size could potentially be used. In both specimen sizes the non-destructive evaluation of mechanical properties reflected the mechanical properties relatively well, suggesting that non-destructive evaluation of timber specimens can present a suitable replacement to destructive testing of specimens under certain conditions.

V okviru praktičnega usposabljanju smo na oddelku za konstrukcijo in razvoj podjetja Oprema Ravne, d. o. o., dobili nalogo izdelati varnostni koncept rabljenega stroja za izdelavo ušesa listnatih vzmeti. Po ogledu stanja stroja smo izdelali idejne zasnove in zahtevnik ter glede na začetno stanje napravili oceno tveganja, kar smo v nadaljnjem postopku konstruiranja celice z ustreznimi varnostnimi ukrepi tudi upoštevali. Z izbranimi dodanimi varnostnimi elementi smo oceno tveganja za tem ponovno ocenili. Ko so bili vsi sestavni deli izdelani in dobavljeni, smo celico ustrezno zmontirali okoli obnovljenega stroja ter z različnimi testi preverili vsa delovanja. Napravljena pa je bila tudi vsa potrebna dokumentacija, od načrtnih risb do vseh ustreznih navodil. As part of the practical training at Oprema Ravne d. o. o at the construction-development division we were given the assignment of making a safety concept of an used eye forming machine for leaf springs. After having a good look at the current state of the machine, we made some concept models and compiled the requester. Based on the current state of the machine, we compiled a risk assessment and took it into consideration in the further construction process by applying the appropriate safety measures. After installing our chosen safety components, we evaluated the risk again. When all the necessary parts were made and delivered, they were assembled around the restored machine. We made sure our concept is operating well by conducting various tests. All the necessary documentation, from drawings to instructions was also prepared.

Timber is by its nature a very heterogeneous material. Many different factors impact its mechanical properties, from tree species to environment (climate, competition, soil…). While a number of studies in the past dealt with sawn timber and its mechanical properties, only a small number of them studied round logs. An even smaller number dealt with logs where moisture content is above fibre saturation point, e.g. green logs. The objective of this study is to investigate and describe the load-deflection response of green Sitka Spruce logs using a four point bending test. The trees for this study were felled at the age of 20 years and consequently the percentage of juvenile wood is relatively high. Green logs behave differently when stressed in comparison to dry timber. The flexural stiffness is significantly lower and the load-deflection response is highly non-linear. The test results are useful for designing further green round log testing, especially when studying wind throw in standing trees, as they can give a clearer picture of the stresses that can be expected. There are significant differences in static and dynamic modulus of elasticity between bottom and top logs from the same tree. More logs will have to be tested to further characterize the nature of those differences. The authors would like to thank Colm Walsh and Gonzalo González Fernández for their help with the testing. The first author would like to gratefully acknowledge the support from a Teagasc Walsh Fellowship in the conduct of this work. peer-reviewed