61. 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, izvirni znanstveni članek Povzetek: 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.
Ključne besede: pubescent oak, leaf development, radial growth, initial earlywood vessel, sieve tube, anatomy, cambial cell production, extreme weather events
Objavljeno v DiRROS: 06.09.2021; Ogledov: 1060; Prenosov: 349
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65. Gostota lesa - metode določanja in pomen pri razvoju gozdno lesnega biogospodarstvaDomen Arnič, Miha Humar, Davor Kržišnik, Luka Krajnc, Peter Prislan, 2021, izvirni znanstveni članek Povzetek: 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.
Ključne besede: lastnosti lesa, gostota lesa, rezistograf, penetrometer, rentgenska denzitometrija, visokofrekvenčna denzitometrija, gozdno lesno biogospodarstvo
Objavljeno v DiRROS: 28.03.2021; Ogledov: 4322; Prenosov: 2552
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66. 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, izvirni znanstveni članek Povzetek: 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.
Ključne besede: Picea abies, xylem formation, phloem formation, cambium, tracheid, sieve cell, conifer, temperate environment
Objavljeno v DiRROS: 22.03.2021; Ogledov: 1226; Prenosov: 866
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67. Predlog kazalnikov stanja gozdno-lesnega sektorja v slovenskem biogospodarstvu : Javna gozdarska služba v letu 2020 : naloga 5: pripravljanje strokovnih podlag in predlogov normativov za opravljanje del v gozdovihDomen Arnič, Špela Ščap, Peter Prislan, Nike Krajnc, 2020, elaborat, predštudija, študija Ključne besede: biogospodarstvo, raba lesa, kaskadna raba, tokovi lesa, krožno gospodarstvo
Objavljeno v DiRROS: 11.12.2020; Ogledov: 1295; Prenosov: 378
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69. Mikroskopske tehnike za študij nastanka lesa pri bukviPeter Prislan, Jožica Gričar, Gerald Koch, Uwe Schmitt, Katarina Čufar, 2008, izvirni znanstveni članek Ključne besede: bukev, Fagus sylvatica L., nastanek lesa, svetlobna mikroskopija, UV mikrospektrofotometrija, transmisijska elektronska mikroskopija
Objavljeno v DiRROS: 17.11.2020; Ogledov: 1509; Prenosov: 459
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70. Growth-limiting factors and climate response variability in Norway spruce (Picea abies L.) along an elevation and precipitation gradients in SloveniaJernej Jevšenak, Ivan Tychkov, Jožica Gričar, Tom Levanič, Jan Tumajer, Peter Prislan, Domen Arnič, Margarita Popkova, Vladimir V. Shishov, 2020, izvirni znanstveni članek Povzetek: Norway spruce (Picea abies L.) is among the most sensitive coniferous species to ongoing climate change. However, previous studies on its growth response to increasing temperatures have yielded contrasting results (from stimulation to suppression), suggesting highly site-specific responses. Here, we present the first study that applies two independent approaches, i.e. the nonlinear, process-based Vaganov-Shashkin (VS) model and linear daily response functions. Data were collected at twelve sites in Slovenia differing in climate regimes and ranging elevation between 170 and 1300 m a.s.l. VS model results revealed that drier Norway spruce sites at lower elevations are mostly moisture limited, while moist high-elevation sites are generally more temperature limited. Daily response functions match well the pattern of growth-limiting factors from the VS model and further explain the effect of climate on radial growth: prevailing growth-limiting factors correspond to the climate variable with higher correlations. Radial growth correlates negatively with rising summer temperature and positively with higher spring precipitation. The opposite response was observed for the wettest site at the highest elevation, which positively reacts to increased summer temperature and will most likely benefit from a warming climate. For all other sites, the future radial growth of Norway spruce largely depends on the balance between spring precipitation and summer temperature.
Ključne besede: Vaganov-Shashkin model, climate-growth correlations, tree rings, process-based modelling, dendroTools, dendroclimatology
Objavljeno v DiRROS: 21.10.2020; Ogledov: 1297; Prenosov: 1027
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