61. Kakovostna lesna goriva za vsakogar : koristne informacije za vse, ki se ogrevajo z lesomNike Krajnc, Mitja Piškur, Peter Prislan, Matevž Triplat, 2014, professional monograph Keywords: energetski viri, ogrevanje, drva, lesni sekanci, lesni peleti Published in DiRROS: 05.01.2022; Views: 1291; Downloads: 406 Full text (4,32 MB) |
62. Stanje žagarske panoge v Sloveniji v letu 2019Špela Ščap, Nike Krajnc, Peter Prislan, 2021, original scientific article Abstract: Z raziskavo, opravljeno v letu 2020, smo želeli ugotoviti stanje žagarske panoge v Sloveniji v letu 2019 (t.j. ocena števila obratov, ocena razžagane količine lesa, uporaba ostankov in vpliv pandemije covid-19 na poslovanje). Pred izvedbo raziskave smo iz različnih podatkovnih baz zbrali seznam 1.128 poslovnih subjektov, ki imajo kot C16 (Obdelava in predelava lesa) registrirano primarno ali sekundarno dejavnost. Izpolnjene vprašalnike nam je posredovalo 588 podjetij, od katerih se jih 328 ukvarja z razžagovanjem hlodovine. V letu 2019 je skupna evidentirana količina razžagane hlodovine znašala 1,71 milijona m3, od tega so z 84 % prevladovali iglavci. Žagarski obrati, ki so sodelovali v anketi, so v letu 2019 proizvedli 633.894 m3 žaganega lesa. Proizvodnja žagovine in lesnega prahu je znašala 237.389 ton, kosovnih ostankov pa 252.655 m3. Epidemija nalezljive bolezni covid-19 in ukrepi za njeno zajezitev so v obdobju od marca do maja 2020 (prvi val) vplivali na poslovanje podjetij v primarni lesnopredelovalni industriji; 63 % sodelujočih podjetij v tem sklopu vprašanj je občutilo posledice epidemije. Keywords: žagarstvo, žagan les, žagarski obrat, predelava okroglega lesa, iglavci, listavci Published in DiRROS: 18.12.2021; Views: 1351; Downloads: 391 Full text (416,31 KB) |
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65. Climatic regulation of leaf and cambial phenology in Quercus pubescens : their interlinkage and impact on xylem and phloem conduitsJožica Gričar, Jernej Jevšenak, Polona Hafner, Peter Prislan, Mitja Ferlan, Martina Lavrič, Dominik Vodnik, Klemen Eler, 2022, original scientific article Abstract: Increased frequency and severity of stressful events affects the growth patterns and functioning of trees which adjust their phenology to given conditions. Here, we analysed environmental effects (temperature, precipitation, VPD and SWC) on the timing of leaf phenology, seasonal stem radial growth patterns, and xylem and phloem anatomy of Quercus pubescens in the sub-Mediterranean in the period 2014%2019, when various adverse weather events occurred, i.e. spring drought in 2015, summer fire in 2016 and summer drought in 2017. Results showed that the timings of leaf and cambium phenology do not occur simultaneously in Q. pubescens, reflecting different environmental and internal constraints. Although year-to-year variability in the timings of leaf and cambial phenology exists, their chronological sequence is fairly fixed. Different effects of weather conditions on different stages of leaf development in spring were observed. Common climatic drivers (i.e., negative effect of hot and dry summers and a positive effect of increasing moisture availability in winter and summer) were found to affect the widths of xylem and phloem increments with more pronounced effect on late formed parts. A legacy effect of the timing of leaf and cambial phenology of the previous growing season on the timing of phenology of the following spring was confirmed. Rarely available phloem data permitted a comprehensive insight into the interlinkage of the timing of cambium and leaf phenology and adjustment strategies of vascular tissues in Mediterranean pubescent oak to various environmental constraints, including frequent extreme events (drought, fire). Our results suggest that predicted changes in autumn/winter and spring climatic conditions for this area could affect the timings of leaf and stem cambial phenology of Q. pubescens in the coming years, which would affect stem xylem and phloem structure and hydraulic properties, and ultimately its performance. Keywords: pubescent oak, leaf development, radial growth, initial earlywood vessel, sieve tube, anatomy, cambial cell production, extreme weather events Published in DiRROS: 06.09.2021; Views: 1181; Downloads: 427 Full text (7,00 MB) This document has many files! More... |
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69. Gostota lesa - metode določanja in pomen pri razvoju gozdno lesnega biogospodarstvaDomen Arnič, Miha Humar, Davor Kržišnik, Luka Krajnc, Peter Prislan, 2021, original scientific article Abstract: Gostota lesa je fizikalna lastnost, ki je enostavno določljiva in nakazuje na številne druge lastnosti lesa in s tem tudi na njegovo uporabnost v lesno-predelovalni industriji, gradbeništvu ali energetiki. Ker je odvisna od vlažnosti ter poroznosti, se v stroki pojavljajo različne definicije gostot lesa, med katerimi je največkrat uporabljena gostota lesa v absolutno suhem stanju. Namen prispevka je predstavitev različnih načinov določanja gostote lesa ter pomen hitrega in natančnega določanje tega parametra kakovosti pri razvoju gozdno lesnega biogospodarstva. V stroki obstaja več neposrednih in posrednih metod določanja gostote; najbolj običajen in razširjen je volumetrični pristop, sledi postopek ocenjevanja gostote s penetrometrom, rezistografom, visokofrekvenčno denzitometrijo, rentgenskimi žarki, infrardečo spektroskopijo ter mikrovalovi. Les je surovina, ki ji bo v prihodnosti pomen še naraščal, saj je ključna za razvoj trajnostnega biogospodarstva. Natančno in pravočasno določanje gostote lesa bo omogočalo ustrezno razporejanje in usmerjanje tokov te surovine med posameznimi konvencionalnimi in novimi sektorji (področji rabe) in posledično bolj učinkovito in trajnostno rabo. Keywords: lastnosti lesa, gostota lesa, rezistograf, penetrometer, rentgenska denzitometrija, visokofrekvenčna denzitometrija, gozdno lesno biogospodarstvo Published in DiRROS: 28.03.2021; Views: 4494; Downloads: 2633 Full text (2,07 MB) This document has many files! More... |
70. Transition dates from earlywood to latewood and early phloem to late phloem in Norway SpruceJožica Gričar, Katarina Čufar, Klemen Eler, Vladimir Gryc, Hanuš Vavrčík, Martin De Luis, Peter Prislan, 2021, original scientific article Abstract: Climate change will affect radial growth patterns of trees, which will result in different forest productivity, wood properties, and timber quality. While many studies have been published on xylem phenology and anatomy lately, little is known about the phenology of earlywood and latewood formation, also in relation to cambial phenology. Even less information is available for phloem. Here, we examined year-to-year variability of the transition dates from earlywood to latewood and from early phloem to late phloem in Norway spruce (Picea abies) from three temperate sites, two in Slovenia and one in the Czech Republic. Data on xylem and phloem formation were collected during 2009-2011. Sensitivity analysis was performed to determine the specific contribution of growth rate and duration on wood and phloem production, separately for early and late formed parts. We found significant differences in the transition date from earlywood to latewood between the selected sites, but not between growth seasons in trees from the same site. It occurred in the first week of July at PAN and MEN and more than two weeks later at RAJ. The duration of earlywood formation was longer than that of latewood formation; from 31.4 days at PAN to 61.3 days at RAJ. In phloem, we found differences in transition date from early phloem to late phloem also between the analysed growth seasons; from 2.5 weeks at PAN to 4 weeks at RAJ Compared to the transition from earlywood to latewood the transition from early phloem to late phloem occurred 25-64 days earlier. There was no significant relationship between the onset of cambial cell production and the transition dates. The findings are important to better understand the inter-annual variability of these phenological events in spruce from three contrasting temperate sites, and how it is reflected in xylem and phloem anatomy. Keywords: Picea abies, xylem formation, phloem formation, cambium, tracheid, sieve cell, conifer, temperate environment Published in DiRROS: 22.03.2021; Views: 1306; Downloads: 925 Full text (1,27 MB) This document has many files! More... |