71. 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, original scientific article Abstract: 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.
Keywords: Vaganov-Shashkin model, climate-growth correlations, tree rings, process-based modelling, dendroTools, dendroclimatology
Published in DiRROS: 21.10.2020; Views: 1334; Downloads: 1071
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72. Timeline of leaf and cambial phenology in relation to development of initial conduits in xylem and phloem in three coexisting sub-Mediterranean deciduous tree speciesJožica Gričar, Andreja Vedenik, Gregor Skoberne, Polona Hafner, Peter Prislan, 2020, original scientific article Abstract: It is unclear how the anticipated climate change will affect the timing of phenology of different tree organs/tissues and thus the whole-tree functioning. We examined the timing of leaf phenology and secondary growth in three coexisting deciduous tree species (Quercus pubescens Willd., Fraxinus ornus L. and Ostrya carpinifolia Scop) from a sub-Mediterranean region in 2019. In addition, we investigated the relationship between leaf and cambial phenology and the onset of the potential functioning of initial conduits, as determined by the completed differentiation process (vessels) or final size (sieve tubes). For this purpose, leaf development was monitored and the microcores of cambium and the youngest phloem and xylem increments were repeatedly collected at 7-10-day intervals during the growing season. The results revealed differences in the timing of leaf development and seasonal radial growth patterns in spring among the studied tree species, depending on wood porosity. We found that cambial cell production started in all cases in the first half of March. However, in ring-porous Q. pubescens and F. ornus, radial growth in the stem occurred more than a month before buds were swollen, whereas in diffuse-porous O. carpinifolia, these two events were detected at almost the same time. The end of cambial cell production occurred earliest in F. ornus (mid-July) and two weeks later also in the other two species. The widest initial earlywood vessels and early phloem sieve tubes were found in Q. pubescens, the narrowest initial earlywood vessels in O. carpinifolia and the narrowest early phloem sieve tubes in F. ornus. This indicates differences in the e%ciency of conducting systems among the studied species. This novel approach of studying phloem phenology and anatomy in relation to leaf and xylem development contributes to a better understanding of how different tree species adapt their structure of secondary vascular tissues in response to environmental change.
Keywords: Quercus pubescens, Fraxinus ornus, Ostrya carpinifolia, earlywood, early phloem, vessel, sieve tube, radial growth
Published in DiRROS: 21.10.2020; Views: 1359; Downloads: 972
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73. Timeline of autumn phenology in temperate deciduous treesInge Dox, Jožica Gričar, Lorène Julia Marchand, Sebastien Leys, Paolo Zuccarini, Charly Geron, Peter Prislan, Bertold Mariën, Patrick Fonti, Holger Lange, Josep Peñuelas, Jan Van den Bulcke, Matteo Campioli, 2020, original scientific article Abstract: Cessation of xylem formation or wood growth (CWG) and onset of foliar senescence (OFS) are key autumn phenological events in temperate deciduous trees. Their timing is fundamental for development and survival of trees, ecosystem nutrient cycling, the seasonal exchange of matter and energy between the biosphere and atmosphere and affect the impact and feedback of forests to global change. A large-scale experimental effort and improved observational methods have allowed us to compare the timing of CWG and OFS for different deciduous tree species in Western Europe, in particularly silver birch, a pioneer species, and European beech, a late-succession species, at stands of different latitudes, of different levels of site fertility, and for two years with contrasting meteorological and drought conditions i.e., the low-moderately dry 2017 and the extremely dry 2018. Specifically, we tested whether foliar senescence started before, after or concurrently with CWG. OFS and CWG occurred generally between late September and early November, with larger differences across species and sites for OFS. Foliar senescence started concurrently with CWG in most cases, except for the drier 2018 and, for beech, at the coldest site, where OFS occurred significantly later than CWG. Behavior of beech in Spain, the southern edge of its European distribution, was unclear, with no CWG, but very low wood growth at the time of OFS. Our study suggests that OFS is generally triggered by the same drivers of CWG or when wood growth decreases in late summer, indicating an overarching mechanism of sink limitation as a possible regulator of the timing of foliar senescence.
Keywords: autumn phenology, xylem formation, foliar senescence, cambium, chlorophyll, radial growth, wood, decidiuous trees, common aspen, common beech, pedunculate oak, silver birch
Published in DiRROS: 10.06.2020; Views: 2053; Downloads: 1289
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74. Inter-individual variability in spring phenology of temperate deciduous trees depends on species, tree size and previous year autumn phenologyLorène Julia Marchand, Inge Dox, Jožica Gričar, Peter Prislan, Sebastien Leys, Jan Van den Bulcke, Patrick Fonti, Holger Lange, Erik Matthysen, Josep Peñuelas, Paolo Zuccarini, Matteo Campioli, 2020, original scientific article Abstract: We explored the inter-individual variability in bud-burst and its potential drivers, in homogeneous mature stands of temperate deciduous trees. Phenological observations of leaves and wood formation were performed weekly from summer 2017 to summer 2018 for pedunculate oak, European beech and silver birch in Belgium. The variability of bud-burst was correlated to previous' year autumn phenology (i.e. the onset of leaf senescence and the cessation of wood formation) and tree size but with important differences among species. In fact, variability of bud-burst was primarily related to onset of leaf senescence, cessation of wood formation and tree height for oak, beech and birch, respectively. The inter-individual variability of onset of leaf senescence was not related to the tree characteristics considered and was much larger than the inter-individual variability in bud-burst. Multispecies multivariate models could explain up to 66% of the bud-burst variability. These findings represent an important advance in our fundamental understanding and modelling of phenology and tree functioning of deciduous tree species.
Keywords: leaf unfolding, wood formation, coloration, Pedunculate oak, European beech, Silver birch
Published in DiRROS: 10.06.2020; Views: 1994; Downloads: 1172
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75. Določanje vlažnosti drv z električnim uporovnim merilnikomPeter Prislan, Domen Arnič, Špela Ščap, Nike Krajnc, Aleš Straže, 2020, professional article Abstract: Vsebnost vode (vlažnost) je med pomembnejšimi kazalniki kakovosti drv. Za čim učinkovitejše in okolju prijazno delovanje Uredba o emisiji snovi v zrak iz malih kurilnih naprav navaja, da mora biti vsebnost vode v drveh manj kot 20 %. Za hitro preverjanje vsebnosti vode v drveh bi bila smiselna uporaba električnih uporovnih merilnikov. V pričujočem prispevku primerjamo meritve, opravljene z elektrouporovnimi merilniki različnih izvedb ter referenčno gravimetrično metodo. Rezultati kažejo, da gravimetrični metodi najbolj primerljive rezultate kažejo uporovni merilniki, ki omogočajo kompenzacijo gostote lesne vrste in temperature. V prispevku razpravljamo o uporabi različne terminologije in definicije lesne vlažnosti (t.j. relativna in absolutna vlažnost lesa, vsebnost vode) ter predlagamo postopek za čim boljšo oceno vlažnosti z enostavnimi elektro-uporovnimi merilniki.
Keywords: lesna goriva, lesna biomasa, vsebnost vode, kakovost drv
Published in DiRROS: 06.04.2020; Views: 2272; Downloads: 714
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76. Raba lesa v slovenskem biogospodarstvuDomen Arnič, Peter Prislan, Luka Juvančič, 2019, original scientific article Abstract: Krčenje zalog fosilnih goriv, netrajnostno izkoriščanje naravnih virov in podnebne spremembe so dejavniki, ki pospešujejo prehod v biogospodarstvo. Tovrsten prehod omogočajo tehnologije in novo znanje pretvorbe biomase v različne produkte, med seboj povezane v kaskadnih in (energetsko in snovno) krožnih proizvodnih ciklih. Eno ključnih področij biogospodarstva je področje rabe lesa, ki trenutno prispeva eno tretjino k skupni dodani vrednosti slovenskega biogospodarstva. Glede na stanje v državah s primerljivimi naravnimi in strukturnimi danostmi Slovenija v razvoju biogospodarstva zaostaja. V pričujočem delu smo predstavili generične dejavnike, ki vplivajo na razvoj biogospodarstva ter pripravili pregled stanja slovenskega biogospodarstva na področju rabe lesa. Stanje slovenskega biogospodarstva uvrščamo v širši evropski okvir ter ocenjujemo nadaljnje možnosti razvoja rabe lesa.
Keywords: biogospodarstvo, lesna biomasa, obnovljivi viri energije, raba lesa, biorafinerije, kaskadna raba lesa
Published in DiRROS: 20.12.2019; Views: 2795; Downloads: 787
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77. Kakovost pelet na slovenskem trgu 2015Peter Prislan, Nike Krajnc, Mitja Piškur, 2015, treatise, preliminary study, study Keywords: kakovost pelet, mehanska obstojnost, vsebnost vode, delež pepela, lastnosti pelet
Published in DiRROS: 12.07.2017; Views: 2646; Downloads: 791
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78. Annual cambial rhythm in Pinus halepensis and Pinus sylvestris as indicator for climate adaptationPeter Prislan, Jožica Gričar, Martin De Luis, Klemen Novak, Edurne Martinez Del Castillo, Uwe Schmitt, Gerald Koch, Jasna Štrus, Polona Mrak, Magda Tušek-Žnidarič, Katarina Čufar, 2016, original scientific article Abstract: To understand better the adaptation strategies of intra-annual radial growth in Pinus halepensis and Pinus sylvestris to local environmental conditions, we examined the seasonal rhythm of cambial activity and cell differentiation at tissue and cellular levels. Two contrasting sites differing in temperature and amount of precipitation were selected for each species, one typical for their growth and the other represented border climatic conditions, where the two species coexisted. Mature P. halepensis trees from Mediterranean (Spain) and sub-Mediterranean (Slovenia) sites, and P. sylvestris from sub-Mediterranean (Slovenia) and temperate (Slovenia) sites were selected. Repeated sampling was performed throughout the year and samples were prepared for examination with light and transmission electron microscopes. We hypothesized that cambial rhythm in trees growing at the sub-Mediterranean site where the two species co-exist will be similar as at typical sites for their growth. Cambium in P. halepensis at the Mediterranean site was active throughout the year and was never truly dormant, whereas at the sub-Mediterranean site it appeared to be dormant during the winter months. In contrast, cambium in P. sylvestris was clearly dormant at both sub-Mediterranean and temperate sites, although the dormant period seemed to be significantly longer at the temperate site. Thus, the hypothesis was only partly confirmed. Different cambial and cell differentiation rhythms of the two species at the site where both species co-exist and typical sites for their growth indicate their high but different adaptation strategies in terms of adjustment of radial growth to environmental heterogeneity, crucial for long-term tree performance and survival.
Keywords: Aleppo pine, Pinus halepensis, Scots pine, Pinus sylvestris, cambium, light microscopy, Mediterranean environment, temporate environment, transmission electron microscopy, xylem
Published in DiRROS: 12.07.2017; Views: 3298; Downloads: 1490
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79. "Za posavski gozd in les"Nike Krajnc, Matjaž Harmel, Špela Ščap, Aleksandra Krajnc, Matevž Triplat, Peter Prislan, Mitja Piškur, 2015, final research report Keywords: Posavje, gozdovi, lesna industrija, gozdno-lesna veriga
Published in DiRROS: 12.07.2017; Views: 2773; Downloads: 801
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80. Analiza potencialnih lokacij za nove dejavnostiAleksandra Krajnc, Matevž Triplat, Matjaž Harmel, Peter Prislan, Nike Krajnc, 2014, treatise, preliminary study, study Keywords: proizvodne dejavnosti, lesnopredelovalni obrati, industrija, prostorski načrti
Published in DiRROS: 12.07.2017; Views: 2575; Downloads: 834
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