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This paper describes the emissions of Volatile Organic Compounds (VOC) emitted by solid Spruce (Picea abies) and Poplar (Populus alba) wood treated at 200 °C and 180 °C. The emissions of VOC from heat treated wood and air-dried (natural) wood were compared with GC-MS analysis. The focus was on the influence of temperature, on the quality and quantity of volatile organic compounds, especially on the amount of emitted phenol and furfural. Furfural and phenol are typical chemicals produced as a result of thermal degradation of wood components. The emission was analyzed as a function of time after heat-treatment. The influence of the finishing with waterborne lacquer on VOC emission was also investigated. The results of this research have shown that heat treated wood emitted more VOC-components of furfural and phenol than untreated wood (natural wood). The amount of emitted VOC declines with increasing the time between wood modification and measurement of VOC emissions emitted by tested samples. Heat treated wood finished by waterborne lacquer emitted a very high concentration of Buthoxy-ethanol. The finished surface does not decrease the amount of emissions escaping from heat-treated spruce and poplar wood., U radu su predstavljeni rezultati istraživanja emisije hlapljivih organskih spojeva (VOC) iz cjelovitog drva smreke (Picea abies) i drva topole (Populus alba), toplinski obrađenoga pri 180 i 200 °C. Emisije VOC-a iz toplinski obrađenog drva i iz prosušenoga neobrađenog (prirodnog) drva uspoređene su primjenom GC-MS analize. Naglasak istraživanja bio je na utjecaju temperature na kvalitetu i količinu hlapljivih organskih spojeva, posebice na količinu emitiranog fenola i furfurala. Furfural i fenol tipični su kemijski spojevi koji nastaju toplinskom degradacijom drvnih komponenata. Emisija VOC-a analizirana je u ovisnosti o vremenu nakon toplinske obrade. Istraživan je i utjecaj završne obrade drva premazima na bazi vode na emisiju VOC-a. Rezultati istraživanja pokazali su da toplinski obrađeno drvo emitira više VOC komponenata furfurala i fenola nego neobrađeno (prirodno) drvo. Količina emitiranog VOC-a smanjuje se s porastom vremenskog razmaka između toplinske obrade drvnih uzoraka i mjerenja emisije VOC-a. Toplinski obrađeno drvo koje je završno obrađeno vodenim lakom emitiralo je vrlo visoku koncentraciju butoksietanola. Završna obrada toplinski obrađenog drva vodenim lakom nije pridonijela smanjenju emisije VOC-a iz toplinski obrađenog drva smreke i topole.

U radu su korišteni podaci izmjere 377 modelnih stabala smreke koja su mjerena u oborenom stanju na širem području unutar državnih raznodobnih sastojina u Kantonu 10 (Hercegbosanski Kanton). Za određivanje volumena krupnog drveta stabala primijenjena je metoda sekcioniranja sa sekcijama nejednakih apsolutnih dužina (najčešće od 1 – 2 m). Za izravnanje veličina volumena krupnog drveta od prsnog promjera i visine stabala primijenjena je metoda višestruke regresijske analize. Za procjenu parametara korištenih funkcija, testiranje značajnosti njihovih razlika te provođenje raznih transformacija, kao softversko rješenje korišteni su StatGraphics Centurion XVII. i Statistica 8.0. U cilju izbora „najboljeg“ modela za procjenu volumena krupnog drveta testiran je veći broj poznatih dendrometrijskih dvoparametarskih volumnih funkcija. Kvaliteta izjednačenja i prikladnost testiranih modela ocjenjivani su na bazi utvrđenih veličina osnovnih statističkih pokazatelja za karakteriziranje jačine korelacijskih veza. Najbolje ocjene parametara pokazao je model V7=a0+a1d1,3+a2h+a3d1,3h+a4d1,32+a5 d1,32h uz utvrđeni koeficijent determinacije: R2 = 0,99 i veličinu standardne greške regresije Sey=0,24 m3. Testirajući značajnost razlika između stvarnih volumena stabala iz uzorka i volumena tih istih stabala utvrđenih primjenom odabranog regresijskog modela, utvrđen je prosječni postotak odstupanja od 0,44%. To znači da su u prosjeku za 0,44% niži volumeni u odnosu na stvarne volumene na uzorku od 377 stabala smreke, što ukazuje da je ovaj regresijski model upotrebljiv za primjenu u praktičnom radu, jer je taj prosječni postotak manji od 1%., For assessment of growing stock in B&H forestry praxis as scientific baseline we are using volume tables and tariffs (Drinići dr. 1990). Having in mind the fact that these are constructed based on volume coefficients of the trees taken from German tree volume tables, which originate from single-age assortments, it is justified to suspect that by applying these tables one will get certain differences in quantity of large wood mass related to the actual status of those volumes. It is known that trees of the same tree species coming from single-age assortments are more full-bodied because they have larger volume coefficients compared to the trees of the same species from variable aged and selection forest assortments. That is why the objective of this research is to find “the best” regression model for levelling of volume of large wood of spruce, as dependent variable depending on diameter at breast height and tree height, as independent variables. To achieve this objective we have selected 377 model trees of spruce that were measured in felled condition on wider area of state owned variable aged assortments in Canton 10 (Livno Canton). To determine volume of large wood of trees we applied section method with sections of uneven absolute lengths (most often from 1 – 2 m). For levelling of volumes of large wood depending on diameter at breast height and tree height we applied method of multi-regression analysis. Quality of levelling and appropriateness of tested models was evaluated on the basis of determined values of basic statistical indicators for characterisation of the strength of correlation connections. The best values of the parameters showed model: V7=a0+a1d1,3+a2h+a3d1,3h+a4d1,32+a5 d1,32h with determined determination coefficient: R2 = 0,99 and size of standard regression error: Sey=0,245 m3. By testing significance of differences between actual/real tree volumes from the sample and volume of those trees determined by application of selected regression model by using t-test of pairs, no statistically significant differences were recorded. Average percentage of deviation was -0.44%. That means that in average we get 0.44% lower volumes comparing to the actual volumes in the sample of 377 spruce trees which shows that this regression model is usable for application in practice, because that average percentage is less than 1%. Statistically significant differences were recorded between volumes of trees of selected regression model and volume tables and models of other authors (Stojanović i dr. 1978; Banković i dr. 2003; Špiranec, 1976.). Those deviations vary in the range from 2.53% up to 22.7%. The largest deviations were determined exactly in model that is used in B&H (Stojanović i dr. 1978) and are in amount of 22.7% while the lower deviations were determined for volumes estimated by using model created for spruce trees from Sub-Alpine belt for area of Kopaonik (Banković i dr. 2003) and those amount to 2.53%.

Mechanisation used in forest utilisation has an impact on the occurrence of damage in stand and on forest land. The research in this work had the objective of determining damage on fir trees and other tree species during felling and processing of trees and their skidding using the forest cable-skidder. The research wasconducted in mixed beech and fir forests in the area of FMA “Glamočko”, M.U. “Hrbinje-Kujača”. The following data were gathered on damaged trees: tree type, breast height diameter, economic importance of the tree, amount of damage, location of damage, cause of damage, types of damage. Damage was recorded on a total of 305 trees, 133 trees of silver fir (Abies alba), 130 trees of European beech (Fagus sylvatica), 33 trees of European spruce (Picea abies), 8 trees of rowan/mountain-ash (Sorbusaucuparia) and one tree of sycamore (Acer pseudoplatanus). The overall damage intensity was 18.7%, but together with the old damages, the overall number of ‘wounds’ is 496. According to this, when the old damage isalso considered, then the intensity of damage amounts to 30.6%. The largest amount of damage is in the diameter sub-class ranging from 10 to 14.99 cm. According to the cause of damage, the largest amount of damage occurred during the wood extraction phase (217 trees), while during the felling phase, 88 trees or 29% were damaged. Since the wood extraction phase is divided into the winching and skidding phases, the total number of damaged trees during the winching phase amounted to 157 or 52%, while during the skidding phase, the number of damaged trees was 60 or 19%. To reduce damage to the trees during following operations in forest utilisation, it is necessary to perform more frequent training of all employees working on forest utilisation, to increase controls in execution of operations during forest utilisation, modernise machines used during forest exploitation, and in quality manner open compartments with forest road infrastructure., Mehanizacija koja se koristi u iskorištavanju šuma utječe na pojavu oštećenja u sastojini i na šumskom tlu. Istraživanja u ovom radu su imala za cilj utvrđivanje oštećenja na stablima jele i drugih vrsta drvća pri sječi i izradi drvnih sortimenata te privlačenju šumskim zglobnim traktorom.Istraživanja su obavljena u mješovitim šumama bukve i jele sa smrekom na području ŠGP „Glamočko”, G.J. „Hrbinje-Kujača“. Prikupljeni su sljedeći podaci o oštećenim stablima: vrsta drveća, prsni promjer stabla, privredna važnost stabla, broj oštećenja, mjesto oštećenja, uzrok oštećenja, vrsta oštećenja.Oštećenja su evidentirana kod ukupno 305 stabala, 133 stabala jele (Abies alba), 130 stabala bukve (Fagus sylvatica), 33 stabla smreke (Picea abies), osam stabala jarebike (Sorbus aucuparia) i jedno (1) stablo gorskog javora (Acer pseudoplatanus). Ukupan intenzitet oštećenja je iznosio 18,7%, a kad tome pridodamo i stara oštećenja, ukupan broj ozljeda iznosi 496. Prema tomu, kada se u obzir uzmu i stara oštećenja, tada intenzitet oštećenja iznosi 30,6%. Najveći broj oštećenja se nalazi u debljinskom stepenu od 10 do 14,99 cm.Prema uzroku oštećenja, najveći broj oštećenja je nastao prilikom faze privlačenja (217 stabala), dok je prilikom sječe oštećeno 88 ili 29% stabala. Kako je faza privlačenja podijeljena na fazu primicanja i privlačenja, ukupan broj oštećenih stabala tijekom faze primicanja iznosio je 157 ili 52%, dok je tijekom privlačenja broj oštećenih stabala iznosio 60 ili 19%.Da bi se prilikom sljedećih operacija iskorištavanja šuma smanjile štete na stablima, potrebna je češća edukacija svih djelatnika koji obavljaju poslove iskorištavanja šuma, potrebno je povećati kontrole obavljanja svih poslova prilikom iskorištavanja šuma, modernizirati strojeve koji se koriste prilikom eksploatacije šuma te na kvalitetan način otvoriti odjele šumskim komunikacijama.

Fenološke razlike prevladujočih drevesnih vrst na območju Pahernikove posesti smo ocenjevali na podlagi satelitskih posnetkov misije Sentinel-2. Analizirali smo normirane diferencialne vegetacijske indekse (NDVI) v obdobju od 29. marca do 15. oktobra 2017. Na podlagi razlik v vegetacijskem indeksu NDVI je mogoče ocenjevati fenološki razvoj prevladujočih drevesnih vrst bukve (Fagus sylvatica L.), smreke (Picea abies L. (Karsten)) in macesna (Larix decidua Mill.) v gozdnih sestojih. Na območju posesti ugotavljamo omejitve ocenjevanja fenološkega razvoja smreke v mešanih sestojih smreke in jelke (Abies alba Mill.), ki imajo podobne vrednosti NDVI. Pri bukvi pa smo ugotovili manjšanje vrednosti NDVI na posnetkih 21. aprila in 5. oktobra z višanjem nadmorske višine, kar povezujemo s poznejšim olistanjem in hitrejšim rumenenjem listov bukve na višjih nadmorskih višinah. Phenological differences of the prevailing tree species in the area of the Pahernik%s estate were estimated on the basis of satellite images by the Sentinel-2 mission. We analyzed the normalized difference vegetation indices (NDVI) in the time period from March 29 to October 15, 2017. It is possible to estimate phenological development of the prevailing tree species European beech (Fagus sylvatica L.), Norway spruce (Picea abies L. (Karsten)), and European larch (Larix decidua Mill.) in forest stands, on the basis of the differences in the vegetation index NDVI. We found limitations in assessing the phenological development of Norway spruce in the mixed Norway spruce and silver fir (Abies alba Mill.) stands, because of the similar NDVI values of Norway spruce and silver fir. We found the decrease of NDVI on the images of April 21 and October 5 with increasing elevation of the beech stands, which we associate with later start of leaf-out and faster start of autumn leaf colouring of the beech trees growing on higher elevations.

V diplomskem delu smo analizirali površino bukovega (Fagus sylvatica L.) in smrekovega (Picea abies (L.) Karst.) lesa, po obdelavi z dielektrično barierno razelektritveno (DBD) plazmo s plavajočo elektrodo. Znano je, da na učinek obdelave površin lesa s plazmo vplivajo zunanji (lastnosti materiala in plina, dimenzije elektrod in reaktorja, električna moč, čas tretiranja itd.) in notranji (lastnosti plazme) dejavniki. Pojav plazme smo posneli s fotokamero in analizirali z računalniškim programom. Z določanjem stičnih kotov vode na obdelanih in neobdelanih površinah lesa smo preučili vpliv spreminjanja zunanjih parametrov naprave na omočljivost lesa. Zunanji parametri, ki smo jih spreminjali, so bili podajalna hitrost, razdalja med dielektrikoma (RME) in oddaljenost površine lesa od dielektrikov (RMES). Z vrstičnim elektronskim mikroskopom smo opazovali strukturo in topografijo površin vzorcev. Izmerjene sive vrednosti analiziranih razelektritev pri obdelavi lesa bukve so bile višje kot pri obdelavi lesa smreke. Rezultati so pokazali, da se stični kot kapljic vode zmanjša z zniževanjem podajalne hitrosti. Površino smrekovega lesa voda bolje omaka pri RMES 0,5 mm, pri bukovini pa pri 1 mm. Optimalna razdalja pri smrekovem vzorcu med elektrodama je 8 mm, pri bukovem pa so najboljši rezultati pri 10 mm. In this thesis, we analysed the surface of beech (Fagus sylvatica L.) and spruce (Picea abies (L.) Karst.) wood after treatment with dielectric barrier discharge (DBD) plasma with a floating electrode. It is known that the effects of plasma treatment of wood surfaces are influenced by external (material and gas properties, electrode and reactor dimensions, electrical power, treatment time, etc.) and internal (plasma properties) factors. Plasma appearance was recorded with a camera and analysed using a computer program. By determining the contact angles of water on treated and untreated wood surfaces, the effect of changing the external parameters of the device on the wettability of wood was examined. The external parameters we varied were the speed of samples, the distance between the dielectrics (RME) and the distance between the wood surface and the dielectrics (RMES). Using the scanning electron microscope, the structure and topography of the sample surfaces were observed. The measured grey values of analysed discharge in the treatment of beech wood were higher than in the treatment of spruce wood. The results showed that the contact angle of the water droplets decreases as the speed of samples decreases. The surface of spruce wood is better wetted with water at RMES 0.5 mm and the surface of beech wood at 1 mm. The optimum RME for the spruce specimen is 8 mm, and for the beech, the best results are at 10 mm.

Proučevali smo vpliv temperature stiskanja na utrjevanje urea-formaldehidnih (UF) lepil. Uporabili smo dve vrsti UF lepil proizvajalca Basf: Kaurit 345 z nižjo vsebnostjo prostega formaldehida in Kaurit 350 z višjo vsebnostjo. Preizkušanci so bili standardni in sicer iz javorjevega furnirja, debeline 0,6 mm. Preizkušanci so se po razrezu klimatizirali pri sobnih pogojih: 23 °C in 55 % vlažnostjo. Kinetiko utrjevanja UF lepil smo izvedli z ABES (Automated Bonding Evaluation System) instrumentom. Lepilna mešanica je bila skozi vse poizkuse konstantna, sestavljena iz 100 utežnih deležev vodne raztopine lepila in 1,5 % katalizatorja - amonijevega sulfata (glede na suho snov lepila). Testiranje je potekalo pri različnih temperaturah stiskanja: 80, 100, 120, 150, 170 °C. Trajanje stiskanja smo prilagajali glede na razvoj strižne trdnosti. Ko je ABES izmeril strižno trdnost večjo od 0, smo meritev pri enakem času stiskanja ponovili vsaj trikrat. Testirali smo tudi vpliv pH vrednosti različnih furnirjev na utrjevanje UF lepil. Ker katalizator zniža pH vrednost mešanice ter pospeši utrjevanje UF lepil, smo enak princip znižanja pH vrednosti ugotavljali s pomočjo različnih lesnih vrst. Vsaka lesna vrsta ima različno pH vrednost, ki tako dodatno pripomore k spremembi kislosti oz. bazičnosti lepilne mešanice med stiskanjem. Testirali smo preizkušance šestih različnih drevesnih vrst (javor, bukev, hrast, oreh, smreka, brest). S pomočjo termočlena smo raziskali spreminjanje temperature v lepilnem spoju med vročim lepljenjem. Ugotovili smo, da je imela temperatura stiskanja bistveni vpliv na hitrost utrjevanja lepila in da hlajenje preizkušanca po stiskanju ni vplivalo na trdnost spoja. Lepilo z višjim deležem formaldehida je utrjevalo hitreje. We studied the effect of pressing temperature on hardening of urea-formaldehyde (UF) adhesives. We used two types of UF adhesives pre-prepared by manufacturer Basf: Kaurit 345 with a lower content of free formaldehyde and Kaurit 350 with a higher content. For testing of kinetics, we used ABES (Automated Bonding Evaluation System) instrument. To preform standard tests, we used maple veneers, with thickness of 0,6 mm. All veneer was prepared and then left for two day at room conditions of 23 °C and 55 % air humidity, to acclimate. Every test has constant adhesive mixture, consisted of 100 weight units of aqueous adhesive solution and 1,5 % catalyst (ammonium sulphate) (according to dry quantity of glue). Bonding strength was investigated at different pressing temperatures: 80, 100, 120, 150 and 170 °C. Times of gluing were adjusted according to feedback of shear strength. If ABES measured sear strength higher than 0 N/mm2, we carried out at least two more tests of strength. pH value of wood was measured. With usage of different veneers, we tested its influence on bond development. For this test, we used six different species (maple, beech, oak, walnut, spruce, elm). With use of thermocouple we investigated temperature changes in bond during gluing process. We found out that the pressing temperature had a significant influence on hardening time. Cooling specimens after gluing process did not have big effect on joint strength. Adhesive with more formaldehyde was curing faster.

V zadnjih letih se je v Sloveniji zelo povečala gradacija gozdov zaradi delovanja smrekovega lubadarja. Les lubadark na trgu dosega nižjo ceno, kot n-razvrednoten les. Uporaba lesa lubadark je v veliki meri odvisna od njegovih lastnosti. Zato smo pomodrelem lesu in kontrolnemu nepomodrelem lesu določili klasične sorpcijske lastnosti, dinamično sorpcijo vodne pare, kapilarni vlek, lastnosti namakanja in odpornost proti glivam razkrojevalkam ter upogibno trdnost in tlačno trdnost. Na podlagi vseh naštetih parametrov smo ugotovili, da pomodrel les hitreje vpija vodo, a ima še vedno enake mehanske lastnosti kot nepomodrel les. In the recent years the damage of forest due to the bark beetles attack has increased considerably. Bark beetle damaged wood has considerably lower price than non-damaged wood. However, the use of such material depends on its relevant properties. Therefore, classic sorption properties, dynamic sorption of water vapour, capillary water uptake, long-term water uptake, durability, bending strength and compressive strength on control and bark beetles damaged spruce wood were determined. Based on all of these parameters, we can conclude that bark beetle damaged wood absorbs more liquid water, but has comparable mechanical properties as reference spruce wood.

V magistrskem delu obravnavamo žledolom, ki je ob koncu januarja in začetku februarja 2014 povzročil gmotno škodo ne le na vegetaciji, temveč tudi na energetski in železniški infrastrukturi. Po dosedanjih ocenah gre za enega izmed najobsežnejših žledolomov na območju Slovenije v zadnjih desetletjih. V raziskavi nas je zanimala prostorska razporeditev sprememb v biomasi bukovih in smrekovih sestojev na z žledom prizadetih območjih, zaznanih s pomočjo satelita Landsat. V raziskavo sta bili zajeti občini Tolmin in Dobrova - Polhov Gradec. Na omenjenih območjih smo primerjali stanje bukovih in smrekovih sestojev pred ledeno ujmo ter po njej. Medtem ko so nam Landsat satelitski posnetki služili kot orodje za determinacijo območij negativnih sprememb v rastlinski biomasi, smo s pomočjo LiDAR podatkov izračunali različne izpeljanke, kot so digitalni model reliefa (DMR), digitalni model krošenj (DMK) in digitalni model površja (DMP). Izračunano gmotno škodo smo finančno ovrednotili na podlagi podatkov povprečnih odkupnih cen lesa, pridobljenih s strani Statističnega urada Republike Slovenije (SURS). Analiza podatkov, izračun izpeljank ter izdelava tematskih kart in grafikonov je potekala s pomočjo programske opreme ArcGIS. In this master’s thesis we examine the problem of the ice storm, which caused material damage not only on vegetation, but also on energy and railway infrastructures. According to previous estimates, this destructive ice storm was one of the most extensive in Slovenia in recent decades. In the study, we examined the spatial dimension of changes in the biomass of beech and spruce forest stands in affected areas, detectable using the Landsat satellite. The study’s research covers municipalities of Tolmin and Dobrova - Polhov Gradec. While the Landsat satellite imagery was used as a tool for determining areas of negative changes in biomass, various variables such as digital elevation model (DEM) and digital surface model (DSM) were calculated by using the LiDAR data. The material damage was financially evaluated according to the national average purchase prices of wood. The data analysis, the calculation of variables, and the production of thematic maps and charts were carried out using the ArcGIS software.

V zadnjem času se razvija vse več okolju ter ljudem prijaznih oblik zaščite lesa. Ena od okolju prijaznih alternativ je tudi termična modifikacija lesa. Ena največjih pomanjkljivosti termične modifikacije je poslabšanje mehanskih lastnosti. Zato smo pred termično modifikacijo les impregnirali še s spojinama bicin ali tricin, da bi videli, če lahko s tem ohranimo odpornost termično modificiranega lesa na vodo in obenem izboljšamo mehanske lastnosti tega lesa. Smrekove in bukove vzorce smo tako zaščitili, nato pa testirali njihove lastnosti. Testirali smo sorpcijske lastnosti, navzem kapilarne vode, stični kot kapljic. Modificiranemu lesu smo določili tudi mehanske lastnosti, in sicer upogibno trdnost, tlačno trdnost in trdoto. Rezultati so pokazali, da impregnacija lesa s tema spojinama pred termično modifikacijo poveča ravnovesno vlažnost in vpijanje kapilarne vode. Mehanske lastnosti se v večini primerov izboljšajo. Lately, more and more environmentally and people friendly types of wood protection are being developed. One of those friendly alternatives is thermal modification of wood. One of the biggest disadvantages of thermal modification is deterioration of mechanical properties. Therefore, prior to thermal modification we impregnated wood with compounds bicine and tricine to see if this can preserve resistance of thermally modified wood to water and at the same time improve its mechanical properties. We impregnated and thermally modificated spruce and beech samples, and then tested their properties. We tested sorption properties, capillary water absorption and contact angle of water. We also determined mechanical properties, namely bending strength, compressive strength and hardness. The results showed that the impregnation of wood with these compounds prior to thermal modification increases moisture content of modified wood and absorption of capillary water. Mechanical properties are improved in most cases.

Zaradi velikih količin manj vrednega pomodrelega lesa, nas zanima, ali lahko takemu lesu dvignemo dodano vrednost s postopkom termične modifikacije. Pomodrele in kontrolne vzorce smrekovine smo modificirali pri dveh temperaturah in na njih izvedli več testov. Zanimala nas je izguba mase po modifikaciji, sprememba barve, tlačna trdnost, upogibna trdnost, stični kot, kratkotrajni in dolgotrajni navzem tekoče vode ter sorpcijske lastnosti. Testi so pokazali, da ima modificiran pomodrel les malo slabše mehanske lastnosti kot nepomodrel. Vse ostale, za termično modificiran les bolj pomembne lastnosti, pa so se izboljšale. Stični kot se je pomodrelim vzorcem po termični modifikaciji znatno povečal, na kontrolne vzorce pa ni imel bistvenega vpliva. Na kratkotrajni in dolgotrajni navzem vode je imela termična modifikacija velik vpliv. Navzem pomodrelih in kontrolnih vzorcev se je zmanjšal na primerljivo vrednost. Termična modifikacija je izboljšala tudi sorpcijske lastnosti ravnovesna vlažnost vseh vzorcev je padla, povečala pa se je tudi sposobnost oddajanja vlage oz. sušenja. Celotna serija poskusov nam je pokazala, da lahko s termično modifikacijo pomodrel les znatno izboljšamo in mu tako dvignemo dodano vrednost. Due to large quantities of blue stained wood with low market value, we aimed to determine whether we can increase its market value with the process of thermal modification. Blue stained and control samples were thermally modified at two different temperatures. A series of tests were then performed. Mass loss, colour change, compressive strength, bending strength, contact angle, short-term and long-term liquid water uptake, and sorption properties were determined. Results have shown that thermally modified wood has deteriorated mechanical properties, but all the other properties have improved with the process of thermal modification. Thermal modification significantly improved contact angle of blue stained specimens, whereas control specimens remained more or less the same. Same goes for short-term and long-term water uptake, both of which performed poorly prior to thermal modification compared to control specimens. Thermal modification improved the blue stained specimens to the point, where the results were comparable to control specimens. Equilibrium moisture content of all thermally modified specimens decreased. Drying velocity was also improved by thermal modification. The series of the performed tests showed that it is possible to improve blue stained wood's properties with thermal modification and therefore greatly increasing its market value.

The aim of the long standing forest ecosystem research was to asses the physiological state of Norway spruce (Picea abies (L.) Karst.) on the basis ofthe needle biochemical parameters in the area infl uenced by sulphur emissions from the Šoštanj Thermal Power Plant (ŠTPP). The total sulphur content, photosynthetic pigments, ascorbic acid (vitamin C) and f -tocopherol(vitamin E) were analysed in current and one year old needles from the seventh whorl from the top in fi ve 60-100 year old spruce trees in autumn every year; the results of current needles are presented in this paper. Ten differently polluted sampling plots were selected in profile: Lajše, Topolšica, Laze, Veliki Vrh, Graška gora, Zavodnje, Brneško sedlo, Kramarica, Kope and Smrekovec. Dominant air pollutants were sulphur dioxides,nitrogen oxides and ozone. Results show that the condition of Norway spruce has improved since 1995 and particularly since 2000 due to installation of desulphurization devices on Units 4 and 5 of the TPPŠ, part ofunexplained fl uctuations in investigated parameters are most probably consequences of variations in climatic conditions. Z dolgoletnimi raziskavami gozdnega ekosistema smo želeli oceniti fi ziološko stanje smreke (Picea abies (L.) Karst.) na osnovi meritev fizioloških parametrov v iglicah smrek vplivnega območja Termoelektrarne Šoštanj (TEŠ). V članku prikazujemo rezultate meritev celokupnega žvepla, fotosintetskih pigmentov, askorbinske kisline (vitamin C) in ?-tokoferola (vitamin E) v iglicah tekočega letnika sedmega vretena 60- do 100-letnih smrek, vzorčenih v jesenskem obdobju tekočega leta. Izbranih je bilo 10 različno onesnaženih vzorčnih mest: Lajše, Topolšica, Laze, Veliki Vrh, Graška gora, Zavodnje, Brneško sedlo, Kramarica, Kope in Smrekovec, izpostavljenih predvsem imisijam žveplovega dioksida, dušikovega oksida in ozonu. Rezultati so pokazali, da se stanje smreke izboljšuje zaradi zgrajenih čistilnih naprav na bloku 4 (1995) in 5 TEŠ (2000). Del nepojasnjenih nihanj vrednosti preučevanih parametrov je po vsej verjetnosti posledica delovanja klimatskih razmer v tem obdobju.

Pri proučevanju propadanja gozdnega drevja na območju Slovenije so sodelavci Inštituta za gozdno in lesno gospodarstvo začeli l. 1985 nabirati vzorce iglic smreke, črnega in rdečega bora na točkah 16x16 km bioindikacijske mreže. Arhivirani rastlinski material smo uporabili za splošno oceno preskrbljenosti gozdnega drevja z mineralnimi hranili na točkah mreže za obdobje od 1987 do 1991 leta. V enoletnih iglicah smo poleg skupnih vsebnosti žvepla določili še vsebnosti glavnih rastlinskih hranil: dušika, magnezija, fosforja, kalija in kalcija. Ocena je pokazala slabo preskrbljenost gozdnega drevja z dušikom in fosforjem. Vsebnosti magnezija so v petih letih nihale od dobre (preskrbljenosti na večini bioindikacijskih točk) do slabše preskrbljenosti, razmeroma ugodne pa so prehranske razmere glede vsebnosti Ca in K.

Norway spruce trees from the subalpine stand are exposed not only to high UV-B radiation but also to a complex of other environmental factors, suchas high photosynthetically active radiation, extreme temperature conditions, deficient water and mineral supply, which might cause stress responses. Current year needles from the subalpine stand exhibited lower photochemical efficiency and total chlorophyll content compared to samples from lower altitudes. The result suggested that young needles were most vulnerable to stress factors, since the protective mechanisms were not fully developed. Current+1 year needles from the subalpine stand exhibited lower ETSvalues and higher total UV-B absorbing compounds, which may be interpreted as most successful protection against UVB radiation of current+1 year needles among the three needle age classes. Despite the obtained results, the effect of a single stress factor on spruce could not be easily drawn out. Still, we may assume that the spruce is quite tolerant to high UV-B radiation and other extreme environmental factors in the mountains. Rastline, ki uspevajo v gorah, so pogosto izpostavljene stresnim razmeram, predvsem povečani jakosti sevanja UV-B, skrajnim temperaturnim razmeram ter pomanjkanju vode in hranil. Odziv smreke na okoljske razmere je kompleksen. Pri enoletnih iglicah v visokogorju smo izmerili manjšo fotokemično učinkovitost in vsebnost klorofilov, kar kaže na občutljivost mladih iglic, kjer zaščitni mehanizmi še niso dokončno razviti. Pri starejših iglicah razlika ni bila več statistično značilna, zato sklepamo, da se poškodbe v drugem in tretjem letu preprečijo ali popravijo. Pri dveletnih iglicah smreke z visokogorskega rastišča je bil dihalni potencial značilno manjši in vsebnostUV-B absorbirajočih snovi značilno večja, kar pojasnjujemo s tem, da so dveletne iglice z visokogorskega rastišča med tremi starostnimi razredi najbolj odporne proti UV-B sevanju. Iz rezultatov sicer ne moremo sklepati, v kolikšni meri je k odzivu rastline prispeval posamezni stresni dejavnik, vendar lahko trdimo, da je smreka razmeroma dobro prilagojena na velike jakosti UV-B sevanja in stresne razmere, kakršne vladajo v visokogorju.

In managed Dinaric montane fir (Abies alba Mill.) and European beech (Fagus sylvatica L.) forests, the light response of young beech and fir in gap microsites was studied during three consecutive growing periods (2009, 2010, and 2011) under controlled environmental conditions in stands of single-tree and irregular shelterwood silvicultural system. According to maximal quantum yield, the different response between species in microsite light categories was evidenced for silver fir on microsites with predominating diffuse light and for beech on microsites with predominating direct light, respectively. Abundance and change of share in microsite light categories was compared over different elevation belts on comparable sites between two silvicultural systems. The share of forest edge area was bigger in the irregular shelterwood system. Change in width of forest edge (20, 30 and 40 m) did not affect the proportion and share of the microsite in both regions of different silvicultural system. Separation of microsite areas between both silvicultural systems, evident in lower elevation belts was not evident in the most conflict and highest elevation zone, while the absolute values of all categories above 700 m in both systems were almost identical, indicating the same, small-scale irregular shelterwood system, known also as the freestyle silvicultural approach.

Proučevanje reagiranje posameznih drevesnih vrst na različne stopnje presvetlitve, razvoj krošnje, prirastki

Boron compounds are very effective fungicides, but they leach from wood in wet environments, unfortunately. In order to improve boron fixation, boric acid, borax and copper(II) sulphate were combined with polyvinyl acetate emulsion (PVA). Selected preservative solutions were chosen for impregnation of Norway spruce wood specimens (Picea abies). Wood blocks were exposed to three wood decay fungi Antrodia vaillantii, Gloeophyllum trabeum and Trametes versicolor according to the mini block procedure. Part of impregnated specimens was leached according to the EN 1250-2 procedure. The results showed that addition of PVA emulsion slightly improves copper and boron fixation. Spruce wood impregnated with the lowest concentration of boron based solutions (cB = 0.1%) was found resistant against tested fungi. In contrast, wood blocks impregnated with copper were sufficiently protected against G. trabeum and T. versicolor but not against A. vaillantii. Furthermore, PVA itself has a negative impact on fungal growth, and it improves performance of boron and copper based aqueous solutions. Borove spojine učinkovito delujejo proti glivam razkrojevalkam, a se na žalost v vlažnem okolju izpirajo iz lesa. Z namenom doseči čim boljšo vezavo v les, smo borovo kislino, boraks in bakrov(II) sulfat pentahidrat kombinirali s polivinil acetatno (PVA) emulzijo. Z izbranimi pripravki smo impregnirali vzorce smreke (Picea abies) in jih izpostavili trem različnim glivam razkrojevalkam lesa (Antrodia vaillantii, Gloeophyllum trabeum in Trametes versicolor) po postopku mini blok. Del impregniranih vzorcev smo izpirali v skladu s standardom SIST EN 1250-2. Ugotovili smo, da dodatek PVA-emulzije rahlo izboljša vezavo borovih in bakrovih ionov v les. Smrekovina, impregnirana s pripravki z najnižjo koncentracijo borovih učinkovin (cB = 0,1 %), je odporna na vse testne glive, medtem ko je les, zaščiten z raztopinami na osnovi bakra, dobro zaščiten pred glivama Gloeophyllum trabeum in Trametes versicolor in neustrezno zaščiten pred glivo Antrodia vaillantii. Dodatek emulzije PVA že sam po sebi nekoliko zavre delovanje gliv in izboljša delovanje bakrovih in borovih učinkovin.

The Zasavje district has been heavily affected by air pollution due to mining,the presence of a coal-fired power plant, and industry. The extent of forest damage differs according to location because of specific climatic and orographic characteristics. Norway spruce damage was estimated by two methods at 10 locations in the Zasavje district using the Slovenian forestry method for the estimation of forest damage (KOVA et al. 1995), and a Czech method forestimation of damage to the branching system and needle loss and discoloration (CUDLIN & CHMELIKOVA 1995). Comparison of the results obtained by the two methods gave similar damage assessments at heavily polluted sites, although the data obtained by the two methods differ due to several environmental parameters. The Czech method did not give as good results as wasexpected. A possible reason might be that spruce trees in the investigated locations are less damaged than those in the Czech Republic, where the method was developed. Zasavje je zaradi rudarjenja, termoelektrarne in bazične industrije že od nekdaj močno onesnaženo. Stopnje poškodovanosti gozdov na posameznih lokacijah v tem območju se razlikujejo zaradi specifičnih klimatskih in orografskih značilnosti. Poškodovanost smreke (Picea abies (L.) Karst) smo ugotavljali na 10 zasavskih lokacijah z dvema metodama: slovensko gozdarsko metodo za ugotavljanje poškodovanosti gozdov (KOVAČ et al. 1995) in češko metodo za ugotavljanje poškodovanosti razvejitve in iglic (CUDLIN / CHMELIKOVA 1995). Na močno onesnaženih točkah so rezultati, ki smo jih dobili z uporabo posameznih metod, podobni, nekoliko se razlikujejo le zaradi nekaterih dejavnikov okolja. Rezultati češke metode so bili slabši od pričakovanj. Razlog bi lahko bilo dejstvo, da so smreke na obravnavanih lokacijah manj poškodovane kot smreke, ki so jih Čehi uporabili pri razvoju omenjene metode.

Reliability of growing stock estimation using tariffs in forest with varied micro site conditions was analysed in case of high karst fi r-beech forest fora spruce tree. Reference bole volumes were calculated with Swiss's three parametric volume functions. Adequate tariffs were selected with standard method, using mean tree diameters and heights, which were calculated from adapted height curves. Adequate tariffs for single sampling plots are different for up to 3 tariff's classes. Difference between growing stock calculated by tariffs and reference growing stock for a spruce tree's stand is-2.8%, whereas for single sampling plots the differences are greater, from -7.0 to 8.6%. The hitherto used tariffs underestimated growing stock by -18.1%in the presented case. Our conclusion is that if tariff for a defi ned area (forest stand or compartment) is representative, with correct method used, the reliability of growing stock estimation is good regardless the varied micro site conditions. Representative selection of tariffs is provided for with measuration on sampling plots that well represent the defi ned area. V mikrorastiščno pestrem visokokraškem jelovo-bukovem gozdu smo na primeru drevesne vrste smreke ugotavljali zanesljivost ocenjevanja lesne zaloge s tarifami. Referenčne volumne dreves smo ugotovili s pomočjo švicarskih trovhodnih volumenskih funkcij. Ustrezno tarifo smo izbrali po ustaljeni metodi, na podlagi srednjega premera in srednje višine, ki smo jo odčitali iz prilagojene višinske krivulje. Razlike med tarifami posameznih vzorčnih ploskev so do 3 tarifne razrede. Odstopanje med lesno zalogo, ugotovljeno s tarifami in referenčno lesno zalogo za smrekov sestoj, je -2,8 %; pri posameznih ploskvah pa so odstopanja večja, od -7,0 do 8,6 %. Dosedanje (prenizko izbrane) tarife dajo v konkretnem primeru za -18,1 % prenizko oceno lesne zaloge. Sklepamo lahko, da v primeru, če je tarifa za površino (odsek, sestoj) izbrana korektno in reprezentativno, dobimo z njo dobro oceno lesne zaloge tudi na mikrorastiščno pestri površini. Reprezentativni izbor tarife zagotovimo z meritvami na vzorčnih ploskvah, ki dobro predstavljajo površino.

Forest damages caused by red deer and some other large herbivore species occasionally feeding on tree bark, are a grave ecological and economic problem in many parts of the world. Winter supplemental feeding is commonly used to mitigate the problem, but its effects are poorly known. This study, carried out at Pohorje (Slovenia) and including over 2,300 trees, used binary logistic regression to analyse the effects of supplemental feeding and many other factors on the probability of bark stripping on spruce. The probability of bark stripping depends on distance from the forest edge, density, age and tree species diversity of stands, slope and aspect of terrain, and red deer density contrary to expectations, it is not related to distance from feeding places. As much as 35% of spruce trees were damaged. The damage was the highest in younger, denser pure spruce stands, whose favourable protective and microclimatic conditions (thinner snow cover, higher effective temperatures) make them a preferred winter habitat for red deer. They contain,however, little other food but bark. To prevent / diminish bark stripping we propose a stronger thinning of such stands. Supplemental feeding may reduce damage only in exceptional cases, when animals are lured and concentrated in less sensitive areas, but in general we advise against the use of this measure due to its other negative effects. Poškodbe gozdov, ki jih zaradi hranjenja z drevesno skorjo povzročajo jelenjad in nekatere druge vrste velikih rastlinojedov, so v mnogih delih sveta resen ekološki in ekonomski problem. Pogosto se ga skuša reševati z zimskim dopolnilnim krmljenjem, katerega učinki pa niso preučeni. V raziskavi,ki je potekala na Pohorju in je zajemala prek 2.300 dreves, smo z logistično regresijo analizirali vplive krmljenja in številnih drugih dejavnikov na pojavljanje poškodb smreke zaradi lupljenja. Pojavljanje poškodb je odvisno od oddaljenosti od gozdnega roba, gostote, starosti in vrstne pestrosti sestojev, nagiba in ekspozicije terena in gostote jelenjadi, proti pričakovanjem pa ne od oddaljenosti od krmišč poškodovanih je bilo kar 35 % smrek. Zlasti so poškodovani mlajši, čisti, gosti smrekovi sestoji, saj so zaradi ugodnih varovalnih in mikro-klimatskih razmer (plitvejša snežna odeja, višje efektivne temperature) priljubljen zimski habitat jelenjadi, v katerem pa razen skorje skoraj ni hrane. Za preprečevanje poškodb zato svetujemo močnejša redčenja takih sestojev. S krmljenjem je verjetno škode mogoče zmanjšati le izjemoma, kadar z njim živali odtegnemo na manj občutljiva območja, sicer pa rabo tega ukrepa zaradi drugih negativnih učinkov v splošnem odsvetujemo.

Navadna smreka (Picea abies (L.) Karst.) je zaradi svoje razširjenosti, zgradbe lesa in dolge življenjske dobe razmeroma pogost objekt dendrokronoloških raziskav. Doslej objavljene slovenske smrekove kronologije so bile sestavljene na podlagi širin branik, prispevek pa predstavlja prve denzitokronologije v Sloveniji in opisuje metodo določanja maksimalne gostote kasnega lesa branike (MXD). Raziskava je potekala na dveh različnih smrekovih rastiščih - Pokljuki in Sorškem polju. Na obeh lokacijah smo v vzorec zajeli po 13 dreves. Rezultati, dobljeni na Sorškem polju, so pokazali višje vrednosti MXD in manjše število značilnih let. Analiza je pokazala tudi pozitivno korelacijo med MXD in temperaturami v avgustu in septembru. Norway spruce (Picea abies (L.) Karst.) is frequently the object of dendrochronological research owing to its distribution, wood structure and longevity. The Norway spruce chronologies published in Slovenia so far have been based on tree-ring widths. This article presents the first density chronologies and describes the method of determining maximum latewood density (MXD). Two different sampling sites were selected (Pokljuka and Sorško polje) and 13 sampling cores were taken from each site. The results showed positive correlation between MXD and temperatures in August and September. Furthermore,higher MXD values and less pointer years were observed at the lowland Sorško polje site.

Seasonal dynamics of xylem formation were studied at a cellular level in Norway spruce (Picea abies) from the lowland forests Sorsko polje (350 m a.s.l.) and the sub-alpine site Pokljuka (1200 m a.s.l.) in Slovenia during the growing season 2003. Th e pinning technique and sampling of intact tissue were performed at weekly intervals to assess the usefulness of both methods for examining wood formation. Pinning induced desiccation of diff erentiated xylem, necrosis of cambial cells and undiff erentiated xylem derivatives, and formation of callus, traumatic resin canals and wound-wood. Th e border between cambial cells and radially expanding cells located inside the callus was a reliable mark for defi ning the xylem increment reached from the time of wounding. Intact tissue sampling was superior for precise investigations of cambial activity, various developmental stages of tracheids, and for secondary phloem formation.

Analizirali smo poškodovanost bukovih gozdov v Sloveniji zaradi snega. V analizo smo vključili 22.609 oddelkov na bukovih rastiščih, na katerih je bil delež bukve vsaj 10 % celotne lesne zaloge sestojev. Količino, strukturo in pogostnost poškodb sestojev zaradi snega smo primerjali s poškodbami bukovih gozdov zaradi vetra in žleda. Največji delež v sanitarnem poseku so imeli vetrolomi, nato snegolomi, takoj zatem žledolomi. Pri snegolomih in vetrolomih je praviloma delež poškodovanih dreves iglavcev precej višji, pri žledolomih pa sta bila deleža listavcev in iglavcev skoraj enaka. V bukovih gozdovih je zaradi snega najbolj poškodovano drevje mlajših in srednjedobnih razvojnih faz. Izmed preučevanih treh klimatskih, štirih sestojnih in petih rastiščnih spremenljivk so bili v model binarne logistične regresije pojavljanja snegolomov vključene količina snega v spomladanskih mesecih (marec, april, maj), fitoregija, skalnatost, naklon terena in matična podlaga. Verjetnost za poškodovanost bukve zaradi snega se povečuje s povečevanjem količine zapadlega snega v spomladanskih mesecih, s povečevanjem naklona terena in z zmanjševanjem skalnatosti. V primerjavi z alpskim območjem je verjetnost poškodb pri enaki količini snega na območju preddinarskih gozdov za 4,2-krat, na območju dinarskih za 3,4-krat in na območju predalpskih bukovih gozdov za 1,9-krat večja. V bukovih gozdovih je bukev manj dovzetna za poškodbe zaradi snega kot smreka, zato lahko razloge za relativno visok sanitarni posek v bukovih gozdovih delno razložimo s spremenjenostjo gozdov zaradi primesi iglavcev. Sneg v bukovih gozdovih v največji meri poškoduje drevje mlajših in srednjedobnih razvojnih faz, zato so z vidika stabilnosti ustreznejša pogostejša redčenja nižjih jakosti. The aim of our study was to analyse snow damage in beech stands in Slovenia. 22.609 compartments with at least 10 % of European beech (Fagus sylvatica) in the total growing stock were included in the research. Amount, structure and frequency of snow breakages in beech forests were compared to damage due to other disturbance agents, namely wind and ice, while factors influencing the occurrence of snow damage were analysed in the second part of the study. The largest share in the sanitary felling accounted to windthrows, followed by snow and ice damage. Conifers were relatively more damaged compared to deciduous species by snow and wind, yet their proportions in ice damage were similar. The majority of damage occured in trees of younger and middle-aged developmental stages. Three climatic, four stand and five site variables have been tested in the binary logistic regression model. Statistically significant predictors were the sum of snow cover in spring months (March, April, May), phytogeographical region, rockiness, slope inclination, and bedrock. The probability of occurrence of snow damage increases with the increasing amount of snow in spring months, with increasing slope inclination, and with decreasing rockiness. The probability of snow damage occurrence in beech forests, at the constant amount of snow, was 4,2-times higher in the predinaric region, 3,4-times higher in dinaric region and 1,9-times higher in the prealpine phytogeographical region if compared to the alpine phytogeographical region. Beech was found as less susceptible to snow damage compared to spruce, therefore the reasons for relatively high sanitary fellings can partly be explained by alterations in forests due to the admixture of spruce. In terms of stands' mechanical stability, thinnings ought to be of lower intensities and carried out in shorter intervals.

Structural indices are often proposed as guiding measures for increasing structural heterogeneity. However, few studies have examined the association between such indices and conventional stand attributes. The primary objectives of this study were to evaluate changes in structural heterogeneity and tree species diversity at different plot sizes and to quantify the relationships between conventional stand attributes (mean tree diameter, absolute tree density, basal area, species proportion) and structural indices in a mixed old-growth forest in Southeast Europe. Paired tests were used to identify significant changes in structural heterogeneity with increased plot area, while the relationships between stand attributes and analyzed indices (Gini, diameter differentiation, species mingling, and Shannon&rsquo, s index) were evaluated with Pearson&rsquo, s correlations. The index values of Gini, diameter differentiation, and tree species mingling were rather stable with the increase of plot size, whereas tree species diversity increased significantly with the increase of plot area from 200 m2 to 1500 m2. The measures of tree species mingling and tree species diversity were strongly associated with each other, while their association with diameter variability was weak to moderately strong. Tree species mingling index was strongly associated with the changes in tree species proportions. However, conventional stand attributes were generally not strongly correlated with the examined indices. For restoring and maintaining old-growth characteristics, forest managers may use structural indices to increase small-scale structural heterogeneity, tree species mingling, and diversity, but only as an additional set of measures, not as surrogates for conventional stand attributes.

Primerjali smo različne volumenske funkcije za ocenjevanje volumnov dreves. S pomočjo sekcijskih meritev (Newtonova metoda) smo izračunali prave ocene volumnov dreves 88 posekanih smrek na Pokljuki. Te smo uporabili za izdelavo regionalnih trovhodnih volumenskih funkcij, (dvovhodnih) deblovnic in tarif. Standardna napaka ocene povprečne vrednosti volumna drevesa je najmanjša pri trovhodnih volumenskih funkcijah (5,0 %), nato pri deblovnicah (11,7 %) in največja pri tarifah (15,1 %). Zanesljivost in uporabnost izdelanih regionalnih ter drugih volumenskih funkcij smo preverili na dveh hektarskih raziskovalnih ploskvah. Ugotovili smo, da s prirejenimi nemškimi deblovnicami smrekam določimo previsoke volumne. Ker volumne iz teh deblovnic uporabljamo tudi pri določanju prirejenih tarif na Slovenskem, je s takim postopkom določen tarifni razred z vsaj za 5 % previsokimi volumni dreves. Various volume functions used for tree volume estimations were compared by the authors. Using section measurements (Newtonʼs method), they calculated the real tree volumes of 88 felled spruce trees on the Pokljuka plateau. The real tree volumes were used to form regional three-entry volume functions, (two-entry) volume tables, and tariff functions. The standard error of the average tree volume estimation is the lowest for three-entry volume functions (5.0%), then for volume tables (11.7%), and the highest for tariffs (15.1%). The reliability and applicability of the developed regional and other volume functions was verified on two one-hectare research plots. It was established that by applying the adapted German volume tables, the measured spruce volumes were too high. As the volumes measured in this manner are used when determining the adapted tariffs in Slovenia, this procedure results in a tariff class of at least 5% too high tree volumes.

V diplomski nalogi sem izvedel statično analizo strešne konstrukcije spomeniško zaščitenega objekta Šenkova domačija s pomočjo programa SAP2000. Spremljal sem kronološko propadanje elementov ostrešja in izdelal parametrično študijo petih računskih statičnih modelov. Osnovni model je sestavljen iz štirih okvirjev s statičnim sistemom povezja s trapeznim vešalom z dodatnim sredinskim stebrom. Mehanske lastnosti smerkovega lesa iz ostrešja, ki so bile potrebne za statično analizo, sem pridobil z laboratorijskimi preiskavami (tlačna in upogibna trdnost, elastični in strižni modul). Raziskoval sem vpliv propadanja posameznih leg in posledično postopnega deformiranja ostrešja na nalegajoče se spodnje poškodovano kamnito zidovje in preverjal, ali je glavni razlog za poškodbe zidov ravno deformacija ostrešja. Najbolj poškodovano je severno zidovje, ki je skoraj v celoti ločeno od ostalega dela objekta. Zato sem se osredotočil predvsem na reakcije in pomike v podporah severne kapne lege, ki leži na poškodovamen zidovju. Z uporabo Evrokodov sem določil obtežbe in upošteval obtežne kombinacije za mejno stanje nostilnosti (MSN). Ugotovil sem, da se je severno zidovje deformiralo zaradi vpliva deformacij ostrešja in posledičnih sprememb prenosa obtežbe ter posedkov. To zidovje namreč nima temeljev. Postavljeno je neposredno na skale, ki ležijo v mehki prodnati zemljini. Ostrešje je bilo dolgo časa brez žlebov, hiša pa brez drenaže, zato je meteorna voda spirala slabo nosilna temeljna tla, kar je vzrok za posedanje severnega zidovja. V določenem obdobju je bilo treba severno kapno lego točkovno podpreti. To pomeni, da je bilo spodnje zidovje nekaj časa brez ugodne vertikalne obremenitve. Posledica točkovnega podpiranja so močno povečane horizontalne reakcije na SV in SZ vogalu zidovja, ki so sprožile začetek nastanka razpok severnega zidovja. This thesis presents the static analysis of the heritage protected Šenk homestead's roof structure with the use of the structural analysis program SAP2000. For this purpose I have analyzed the chronological decay of roof structure elements and made a parametrical study of six static roof structure models. The basic model has four frames with a trapeze shaped triple roof static system Mechanical parameters for the calculation of spruce elements (compressive strength, bending strength, elastical mosulus, shear modulus) for statical analysis were gained by laboratorical testing of spruce samples. I have researched how gradual decay of the roof structure have influenced the deformation of the underlying stone walls. The northern walls are the most damaged with the widest cracks and are almost completely seperated from the rest of the house. Vertical reactions and displacemants of the roof wall plate roller supports were therefore the main focus of this analysis. Dead load, live load, snow load and wind load are assesed using Eurocode standards. Static analysis is based on the method of limit state load (MSN). Analysis shows that the main reason for the north wall deformation is the influence of deformed roof structure and ground setlement. The house is without a foundation and its walls sit directly on rocks that are laying in in soft gravel soil. The house was without gutters and drainage for a long time. Rainwater was therefore able to wash away the soft subgrade causing additional subgrade subsidence. The roof wall plate had to be supported at some point in time, which means that the north wall was without vertical load and consequently constant compressive stress, that had a positive effect on it. As a result the northern wall was able to deform even more. Point supported roof wall plate caused greatly increased horizontal reactions in NE and NW corner of the north wall, that have triggered the beginning of the formation of cracks.

Temporal dynamics of cambial activity and wood and phloem formation was monitored in European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst.) at the sites Panška reka near Ljubljana (400 m a.s.l.) and on Menina planina (1200 m a.s.l.) from 2006 until 2014. The monitoring is based on histometrical analysis of stem tissues of adult trees including cambial zone, xylem (wood) and phloem. Samples (micro cores) for analyses were taken from trees using a Trephor tool at weekly intervals during the growing seasons. Micro cores were embedded in paraffin in order to cut cross-sections and make permanent slides for observations under the light microscope. We always measured the width or counted the number of cells in the cambium, forming xylem and forming phloem increments. The measurements or counting were performed along three radial files of xylem and phloem growth rings and the cambial zone. We recorded the phases of xylem formation: PC – post-cambial extension growth, SW – deposition of secondary wall and lignification, MT – mature cells. In phloem we separately recorded the formation of early and late phloem. Research on beech was conducted in 2006 and from 2008 until 2014, and on spruce from 2009 until 2014. The monitoring and sampling continues. We present some main findings on the beginning, dynamics and cessation of processes which lead to formation of wood and phloem annual growth layers in beech and spruce from both sites. We show how the processes depend on climatic factors. We also present how the spruce data included in a global data set of conifers helps to predict how tree productivity (and survival) will change due to climatic change. The described processes and their variability are still poorly understood it is therefore necessary to continue the research presented. The results provide basic knowledge to better understand productivity of trees and forest stands, wood quality, the impact of climate change on tree growth and survival, accumulation of carbon and other processes.

The purpose of this study is to investigate the productivity and cost of the Urus MIII skyline yarder during extraction of timber from spruce stands in northeast Turkey. The productivity of Urus MIII skyline yarder was determined by using the methods of work and time study. The research results implies that some working characteristics of the Urus MIII skyline yarder such as fuel consumption, load volume, yarding distance, speed of the carriage, time consumption per phases have an important impact on productivity of the skyline yarder. The results indicated that the productivity of Urus MIII skyline yarder was 10.63 m³/hr for average 253 m. Daily productivity was found 84.80 m³. The unit cost of yarder was found to be 30.00 €/hr. Also, the average fuel consumption was 5 liter/hr., Cilj je ovog rada istražiti produktivnost i troškove žičare Urus MIII tijekom iznošenja drva iz sastojina smreke u sjeveroistočnoj Turskoj. Produktivnost žičare Urus MIII određena je uporabom povratne metode studija rada i vremena. Rezultati istraživanja ukazuju da neke radne karakteristike žičare Urus MIII, kao što su potrošnja goriva, obujam tovara, udaljenost iznošenja, brzina iznošenja i utrošeno vrijeme po ciklusu, imaju važan učinak na produktivnost žičare. Dobiveni rezultati pokazuju da je produktivnost žičare Urus MIII iznosila 10,63 m³/h za srednju udaljenost iznošenja drva od 253 m. Dnevna produktivnost bila je 84,80 m³. Jedinični trošak rada žičare iznosi 30.00 €/h. Također, prosječna potrošnja goriva iznosila je 5 litara/h.

V srednji Evropi je veter glavni abiotski dejavnik dinamike gozdov. V gozdovih največkrat povzroča motnje nizkih jakosti, dokaj pogosto tudi srednjih, redkeje pa motnje velikih jakosti, kakršna se je leta 2008 zgodila na območju prelaza Črnivec. V naši raziskavi smo s Kendallovim tau-b korelacijskim koeficientom in binarno logistično regresijo poskušali raziskati, ali lahko s podatki s stalnih vzorčnih ploskev (SVP) analiziramo pojavljanje vetrolomov v izbranem območju gozdov. Številne sestojne in rastiščne spremenljivke so bile statistično značilno povezane s stopnjo poškodovanosti sestojev na SVP. Med razvojnimi fazami smo najvišjo stopnjo poškodovanosti evidentirali v debeljakih, v mladovju in drogovnjaku poškodbe niso bile evidentirane. Sestoji z večjim deležem smreke so bili bolj poškodovani kot sestoji z manjšim. Največjo stopnjo poškodovanosti sestojev smo ugotovili v sestojih s primesjo listavcev < 25 % lesne zaloge, medtem ko vsestojih z deležem listavcev Ž 75 % poškodb nismo zabeležili. V pojasnjevalni model pojava vetroloma na SVP je bilo vključenih sedem spremenljivk: nadmorska višina, lega, nagib, matična podlaga ter lesne zaloge smreke, jelke in bukve. V razpravi so podani komentarji rezultatov in nekatere usmeritve za gospodarjenje z gozdovi. In Central Europe wind was recognized as the main abiotic factor of forest stand dynamics. It mostly causes low-severity disturbances, but also disturbances of moderate severity are frequent, whereas high-severity disturbances are rare. However, one such disturbance happened at the broader area of the mountain pass Črnivec in the year 2008. In the study, Kendall tau-b correlation coefficient and binary logistic regression were used to find out whether the data from permanent sample plots (PSP) can be used to analyze the occurrence of a windthrow on a study site. Various stand and site factors were statistically significantly associated with the damage level in aparticular stand. The highest damage level within the development phases was recorded in mature stands, whereas no damage was documented in regeneration, thicket stage and pole stage stands. Stands with a higher share of conifers were more severely damaged than those with a lower share of conifers. The most severe damages were found in stands with < 25 % of broadleaves in stand volume, while in stands with the share of broadleaves Ž 75 % no damage was registered. The explanatory model of windthrow occurrence at PSP level included seven variables: altitude, exposition, slope, bedrock type, and stand volume of spruce, fir and beech, respectively. Additionally, the acquired results were discussed and some forest management guidelines were proposed.

Dolgoročno dinamiko jelovo-bukovih gozdov v Sloveniji v treh prostorsko ločenih objektih (Leskova dolina, Trnovo in Jelovica) smo proučevali s podatki, ki smo jih pridobili iz gozdnogospodarskih načrtov in gozdarskih kart. Podatkovna zbirka GIS je obsegala podatke iz obdobja po letu 1897 za Trnovo, po letu 1899 za Jelovico in po letu 1912 za Leskovo dolino. Za analizirano obdobje smo ugotovili znatne spremembe proučevanih sestojnih znakov (debelinske strukture, lesne zaloge, raznolikosti debelinske strukture in drevesne sestave). Med objekti je različna velikost in usmerjenost sprememb sestojnih znakov. Nanje vplivajo mnogi dejavniki med pomembnejšimi so prejšnja raba gozdov, vpliv velikih rastlinojedov in rastiščne razmere. The long-term dynamics of silver fir-European beech forest stands in Slovenia were studied in three geographically dislocated study areas, Leskova dolina, Trnovo and Jelovica. In the study archival forest management plans and maps for the past century were used to create the GIS database. It included the data for the period after 1897 for Trnovo study area, after 1899 for Jelovica study area, and after 1912 for Leskova dolina study area. Substantial changes in diameter structure, stand volume, tree size diversity and tree species composition were documented, significantly differing between the study areas. Found stand dynamics were underpinned by a complex array of influential factors, among which past forest use, the impact of large ungulates and site conditions stood out.

Predstavljamo povezave med vizualno ugotovljenimi značilnostmi konstrukcijskega žaganega lesa izdelanega iz slovenske smrekovine (Picea abies(L.) Karst.) in njegovimi mehanskimi lastnostmi. Posušen žagani les smo vizualno razvrstili v sortirne razrede na podlagi SIST DIN 4074-1. Rezultate vizualnega razvrščanja smo primerjali z dobljenimi odločilnimi lastnostmi (upogibna trdnost, modul elastičnosti in gostota). Upogibna trdnost je bila najbolj odvisna od širine branike (r=-0,52), deleža grč (r=-0,50), zvitosti (r=-0,23) in oddaljenosti od stržena (r=0,12). Sortirni razred je bil najpogosteje dodeljen na podlagi ocene grč, sledijo zvitost, prisotnost stržena in širina branike. 10 % preskušancev je bilo razvrščenih v razred S13,58 % v razred S10, 15 % v razred S7, 17 % pa je bilo izločenih. Ugotovljene karakteristične vrednosti sortirnih razredov S13, S10 in S7 so bile višje od zahtev SIST EN 338 za trdnostne razrede C30, C24 oz. C18. Rezultati raziskave predstavljajo osnovo, na podlagi katere bo omogočeno prevajanje sortirnih razredov v trdnostne. We present correlations between visually determined characteristics of structural sawn timber produced from Slovenian spruce (Picea abies (L.) Karst.) and its mechanical properties. Dried sawn timber was visually graded into sorting classes according to SIST DIN 4074-1. Results of visual grading were compared with grade determining properties (bending strength, modulus of elasticity and density). The main strength reducing charasteristics were the rate of growth (r =- 0.52), knot ratio (r =- 0.50), twist (r =- 0.23) and distance from the pith (r = 0.12). The most decisive factors to judge lower grade were however knots, followed by twist, the presence of pith and rate of growth. 10% of the specimens were graded to class S13, 58% to class S10, 15% to class S7, 17% of the specimens were rejected. The determined characteristicvalues of sorting classes S13, S10 and S7 were higher than the requirements of SIST EN 338 for the strength classes C30, C24 and C18 respectively. The results of this study represent a basis on which visual grades can be assigned to a strength classes.

V prvem delu diplomskega dela predstavljamo gozdni rezervat Smrečje. V drugem delu pa prikazujemo splošne pomladitvene razmere, izbrane ekološke dejavnike, ki zavirajo naravno pomlajevanje, in analizo razmerja med odraslim sestojem inmladjem v dveh odsekih, ki ju je prizadel vetrolom. V ta namen smo leta 2007postavili 211 vzorčnih ploskvic v devetih transektih. Na vsaki vzorčni ploskvici smo opisali vrsto, nagib in lego terena, zastiranje pritalne vegetacije, skal in lesnih ostankov. Sledilo je štetje osebkov, ki so na vzorčni ploskvici, ter na koncu še ocena difuzne svetlobe. V raziskavi smo potrdili negativen vpliv pritalne vegetacije na pomlajevanje smreke in bukve ter različne ekološke zahteve obeh drevesnih vrst. Ugotovili smo ugoden vpliv odmrlega lesa na pomlajevanje smreke ter razlike v zmesi mladja in odraslega sestoja. Nakazan je dolgoročen trend zmanjševanja smreke in povečanja listavcev. Raziskava je nakazala dolgotrajen in zahteven proces naravne obnove. In the first part of the graduate thesis an overview of the forest reserve Smrečje is given. In the second part two different stands damaged by wind-throw are compared concerning overall tree regeneration condition, selected ecological factors which hinder natural regeneration, and relation between mature stand and regeneration. For this purpose 211 research plots in nine transects were established in 2007. Relief, slope inclination, exposure as well as ground vegetation, coarse woody debris (CWD) and stone / rock coverage were estimated on each research plot. Additionally tree seedlings were counted according to height classes, and diffuse light was estimated. A negative relation between ground vegetation and Norway spruce and beech regeneration as well as their different ecological niches were confirmed. A positive relation between Norway spruce regeneration and CWD, as well as differences in mixture of regeneration and mature stand (succession) were established. A long term trend of decreasing share of Norway spruce and increasing share of broadleaves was shown. The research revealed a long-lasting and difficult process of forest natural regeneration