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The effect of bedrock and species mixture on wood density and radial wood increment in pubescent oak and black pine
Luka Krajnc, Polona Hafner, Jožica Gričar, 2020, izvirni znanstveni članek

Povzetek: Wood density and radial wood increment were examined in trees of pubescent oak (Quercus pubescens Willd.) and black pine (Pinus nigra Arnold., subsp. nigra) in relation to stand mixture and underlying bedrock. Trees of both species from pure and mixed stands were sampled across two types of bedrock, limestone and flysch. Trees from each species were similar in age. Wood density was estimated in standing trees using resistance drilling and increment cores were taken from a smaller subsample of trees of both species. Tree-ring, earlywood and latewood widths were measured and compared to radial profiles of wood density. The influence of stand mixture, diameter at breast height and bedrock on wood density was examined using a Bayesian general linear model. Wood density was significantly higher in pubescent oak than in black pine. Stand mixture was found to affect wood density positively, although the magnitude of the effect was relatively small when compared to other influencing factors also included in the current study. The effect of diameter on wood density was positive on both bedrocks in pubescent oak and negative or neutral in black pine. The size of the effect varied by bedrock and species. On flysch bedrock, the influence of diameter on wood density was stronger than it was on limestone. These indirect bedrock effects on wood density are probably a result of different soil fertility rather than the bedrock itself. There was a notable difference in radial wood increment in both species across the two bedrocks, whereas the differences in densities were smaller. Higher wood densities found on flysch in the subsample of pubescent oaks are likely an effect of higher proportions of latewood, while the opposite trend was observed in black pine. Higher wood density was found on limestone in black pine despite higher latewood percentages on flysch. In the context of forest management, the species composition of the naturally occurring mixtures in the sub-Mediterranean region should be adjusted slightly to favor pubescent oak, since it is a climax species and will bind more carbon for longer than black pine due to higher wood densities. Future forest management should also promote the overall development of pubescent oak trees in sub-Mediterranean stands. The results are especially important in the European context, because the share of sub-Mediterranean stands is expected to rise with global warming.
Ključne besede: Karst, wood structure, resistograph, resistance drilling, Quercus pubescens, Pinus nigra, limestone, flysch
Objavljeno v DiRROS: 14.01.2021; Ogledov: 641; Prenosov: 31
.pdf Celotno besedilo (1,42 MB)
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3.
Effects of various cutting treatments and topographic factors on microclimatic conditions in Dinaric fir-beech forests
Janez Kermavnar, Mitja Ferlan, Aleksander Marinšek, Klemen Eler, Andrej Kobler, Lado Kutnar, 2020, izvirni znanstveni članek

Povzetek: Forest microclimate is strongly affected by local topography and management activities, as these directly alter overstory structure. In the present work we analysed the dependence of observed patterns of spatio-temporal microclimatic variations on topographic, canopy- and management-related factors. A forestry experiment was conducted in managed fir-beech forests in the Dinaric Mountains (Slovenia), which are characterized by rugged karstic terrain with numerous sinkholes. In 2012, cutting treatments representing a range in the intensity of overstory removal were performed: uncut controls (CON), 50% cut of stand growing stock (intermediate management intensity % IMI) and 100% cut (high management intensity % HMI) creating 0.4 ha canopy gaps. Fine-scale variation in aspect and slope and its effects on microclimate was assessed by comparing central, south-facing and north-facing within-sinkhole positions. We measured microclimatic variables (air temperature % T, relative humidity % RH) 0.5 m above the ground over three consecutive post-treatment growing seasons. Microclimatic variables showed an increase (T and vapour pressure deficit % VPD) or decrease (RH) with management intensity. Daily Tmax and VPDmax in HMI treatment were up to 5.9°C (on average 3.5°C) and up to 1.4 kPa (on average 0.6 kPa) higher than those in CON treatment, respectively, whereas daily RHmin was up to 22.7 (on average 13.0) percentage points lower. Regarding intra-seasonal patterns, microclimatic differences between treatments were largest during the summer. South-facing plots in the HMI treatment overall exhibited the most extreme conditions, i.e. the highest Tmax and lowest RHmin. Differences in microclimate between treatments were strongly modulated by canopy cover. The results also suggest that overstory removal increases topography-mediated variation in microclimate, as evidenced by significant differences in T, RH and VPD along the fine-scale topographic gradient within the created canopy gaps.
Ključne besede: tree cutting, air temperature, relative humidity, vapour pressure deficit, karst topography, canopy cover
Objavljeno v DiRROS: 08.10.2020; Ogledov: 824; Prenosov: 275
.pdf Celotno besedilo (1,59 MB)
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4.
Evaluating short-term impacts of forest management and microsite conditions on understory vegetation in temperate fir-beech forests : floristic, ecological, and trait-based perspective
Janez Kermavnar, Aleksander Marinšek, Klemen Eler, Lado Kutnar, 2019, izvirni znanstveni članek

Povzetek: Forest understory vegetation is largely influenced by disturbances and given local abiotic conditions. Our research focuses on the early response of understory vegetation to various forest management intensities in Dinaric fir-beech forests in Slovenia: (i) control, (ii) 50% cut of stand growing stock, and (iii) 100% cut of stand growing stock. Apart from identifying overstory removal effects, we were interested in fine-scale variation of understory vegetation and environmental determinants of its species composition. Vegetation was sampled within 27 karst sinkholes, which represent a dominant landform in studied forests. Within each sinkhole, five sampling plots, varying in slope aspect (centre, north, east, south, west), were established (135 in total), where pre-treatment (in 2012) and post-treatment (in 2014) floristic surveys were conducted. The sampled understory species were characterized in terms of Ellenberg's indicator values (EIVs) and plant functional traits (plant height, seed mass, specific leaf area, leaf dry matter content). Diversity metrics (species richness, total cover, Shannon index) increased in plots where the silvicultural measures were applied. Tree species richness also increased in 100% cutting. A redundancy analysis revealed that species composition was related to environmental variables, which are directly influenced by management interventions (overstory canopy cover, microclimate maximum daily temperature, soil properties thickness of organic soil layer) as well as by topographic factors (slope inclination and surface rockiness). EIVs for light were significantly affected by treatment intensity, whereas soil-related EIVs (moisture, reaction, nutrients) depended more on the within-sinkhole position. Canopy gaps, compared with uncut control plots, hosted a higher number of colonizing species with a higher plant height and smaller seeds, while leaf traits did not show a clear response. We found a negative correlation between pre-treatment species (functional) richness and post-treatment shifts in floristic (functional) composition. Plots with higher richness exhibited smaller changes compared with species-poor communities. Incorporating different perspectives, the results of this study offer valuable insights into patterns of understory vegetation response to forest management in fir-beech forests.
Ključne besede: canopy gap, microsite environment, Ellenberg indicator values, plant functional traits, compositional resistance, karst topography, fir-beech forest
Objavljeno v DiRROS: 06.12.2019; Ogledov: 1919; Prenosov: 1058
.pdf Celotno besedilo (1,95 MB)
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5.
Ectomycorrhizae of Norway spruce from its southernmost natural distribution range in Serbia
Marina Katanić, Saša Orlović, Tine Grebenc, Marko Bajc, Saša Pekeč, Milan Drekić, Hojka Kraigher, izvirni znanstveni članek

Povzetek: Norway spruce (Picea abies Karst.) reaches its southernmost limit in the mountainous regions of south Serbia and Bulgaria. The species is a regionally important timber species for the wood industry and a significant host for various ectomycorrhizal fungi, including edible species. We analysed ectomycorrhizal community and fine root parameters of high continental / subalpine Norway spruce stands at three sites (Stara planina, Kopaonik, Tara) located in protected areas in Serbia. In addition, we assessed the potential effects of altitude and growing season on the ectomycorrhizal diversity and fine root parameters. Using standardised sampling in combination with morpho-anatomical and molecular identification of ectomycorrhizae, we recorded 29 different anatomorphotypes. None of the identified fungi belonged to commercial edible fungal species. Compared to other Norway spruce ectomycorrhiza studies in central Europe, sites in Serbia exhibited lower species diversity and different dominant species composition, with Cenococcum spp. and Russula spp. as the dominant ectomycorrhizal fungi. A number of ectomycorrhizal types and the value of the species richness index differed between Stara planina and Tara in the autumn, but the influence of site and season on the studied diversity indices was not significant. The total number of fine roots increased in the spring, while percentage of vital ectomycorrhizal root tips increased in the autumn. This study was the first examination of Norway spruce ectomycorrhizal communities at the edge of the natural geographical range of the species.
Ključne besede: ectomycorrhiza, Picea abies Karst, community structure, fine roots
Objavljeno v DiRROS: 22.01.2019; Ogledov: 2035; Prenosov: 1171
.pdf Celotno besedilo (553,32 KB)
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6.
Resin yield of Pinus nigra and Pinus sylvestris in the Slovenian Karst
Domen Gajšek, Miha Brecelj, Kristjan Jarni, Robert Brus, 2018, izvirni znanstveni članek

Povzetek: The aim of our research was to study the impact of various environmental factors on the resin production of pines in the Slovenian Karst. Five plots were established % three in Pinus nigra (Arnold) stands and two in Pinus sylvestris (L.) stands. On each plot, the 19-20 most vigorous dominant or codominant trees with a minimum diameter at breast height (DBH) of 20 cm were selected and their resin yield analysed in 2012. Resin yield in P. nigra was considerably higher than that in P. sylvestris. The average resin yield per tree during the study period of 102 days was 1.144 kg for P. nigra and 0.612 for P. sylvestris. There were substantial differences in resin yield among individual trees in the study period: 0.336-2.487 kg for P. nigra and 0.249-1.270 kg for P. sylvestris. The resin yield in P. nigra was considerably higher for the trees with larger DBH, while this was not the case in P. sylvestris. Tree species was the most important factor in resin yield. Increased precipitation resulted in higher resin yields on most plots, whereas better site productivity positively affected resin yield on all P. nigra plots but not on P. sylvestris plots.
Ključne besede: Black pine, Scots pine, resin production, resin yield, Slovenian Karst
Objavljeno v DiRROS: 05.07.2018; Ogledov: 3332; Prenosov: 2102
.pdf Celotno besedilo (1,78 MB)
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7.
Genetic diversity of core vs. peripheral Norway spruce native populations at a local scale in Slovenia
Marjana Westergren, Gregor Božič, Hojka Kraigher, izvirni znanstveni članek

Povzetek: We investigated the levels of genetic diversity and population differentiation among core and peripheral populations of Norway spruce along an altitudinal gradient (from inversions to upper tree line) using isoenzymes (ISO) and nuclear simple-sequence repeats (SSR) markers on overlapping set of populations. Twenty-seven to seventy trees from 11 and 7 populations were genotyped with isoenzymes and SSRs, respectively. The results partially conform to the expectations of the central-peripheral hypothesis (CPH) and are consistent for both marker sets. Genetic differentiation among peripheral populations was low but significantly different from zero (FST-ISO = 0.013, FST-SSR = 0.009) and higher than that among core populations (FST-ISO = 0.007, FST-SSR = 0.005), conforming to central peripheral hypothesis. Contrastingly, levels of genetic diversity assessed by both richness and equitability measures did not significantly differ between peripheral and core populations (AR-ISO = 2.20 vs. 2.14, AR-SSR = 17.16 vs. 17.68, HE-ISO = 0.183 vs. 0.185, and HE-SSR = 0.935 vs. 0.935 for peripheral and core populations, respectively).
Ključne besede: central peripheral hypothesis, Picea abies (L.) Karst., genetic diversity, genetic differentiation, upper tree line, inversion
Objavljeno v DiRROS: 07.05.2018; Ogledov: 7346; Prenosov: 1326
.pdf Celotno besedilo (561,16 KB)
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Dendroekološka analiza rasti smreke (Picea abies (L.) Karst.) v okolici dveh termoelektrarn
Tom Levanič, Andreja Slapnik, 2006, izvirni znanstveni članek

Povzetek: Namen študije je bil analizirati širine branik pred obdobjem največjega onesnaževanja z SOo2, med tem obdobjem in po sanacijskih ukrepih, opravljenih na termoelektrarnah Šoštanj (TEŠ) in Trbovlje (TET). Analiza širin branik preživelih dreves na ploskvah bliže TET in TEŠ je pokazala, da so bile branike v obdobju največjega onesnaževanja znatno ožje kot tiste na manj vplivanih lokacijah. Izkazalo se je tudi, da je odziv dreves na klimatske vplive na bolj in manj vplivanih ploskvah sicer primerljiv - vsa drevesa so se odzivala enako, vendar tista bliže termoelektrarnam bolj, tista z bolj oddaljenih ploskev pa manj in so se tudi hitreje vrnila v stanje normalnega priraščanja kot prizadeta drevesa. Primerjava rasti s klimo je pokazala, da je večina pozitivnih in negativnih značilnih let sicer posledica klimatskih dejavnikov, vendar pa lahko nekatera značilna leta na ploskvah bliže virom onesnaževanja nedvoumno pripišemo postopnemu povečevanju proizvodnje v termoelektrarnah in posledičnemu povečevanju emisij SO2 v ozračje. Na osnovi teh ugotovitev sklepamo, da je vpliv termoelektrarn na debelinski prirastek drevja omejujoč. Proizvodna sposobnost rastišč ni izkoriščena, drevesa so v konstantnem stresu, na dodatne okoljske strese se odzivajo občutljiveje kot drevesa zunaj vplivnega območja, normalizacija rasti po nastopu ugodnih rastnih razmer pa je daljša. Po namestitvi odžvepljevalnih čistilnih naprav v TEŠ in postavitvi odvodnika v TET so se razmere za rast dreves v okolici termoelektrarn izboljšale, kar se kaže tudi v postopoma vedno manjših razlikah med rastjo dreves na vplivnih in manj vplivnih območjih. Izboljšanje rasti prizadetih dreves je bolj izrazito v okolici TEŠš, kjer je bila ekološka sanacija učinkovitejša; manj pa se je rast izboljšala v okolici TET, kjer je 360 m visoki odvodnik emisije samo razpršil na večje območje.
Ključne besede: onesnaženost zraka, SO2, žveplov dioksid, propadanje gozdov, dendroekologija, debelinski prirastek, smreka, Picea abies (L.) Karst., termoelektrarne, Slovenija
Objavljeno v DiRROS: 12.07.2017; Ogledov: 2965; Prenosov: 1086
.pdf Celotno besedilo (2,49 MB)

10.
Genetski vidik naravne obnove smrekovega sestoja na nastali raziskovalni ploskvi Šijec na Pokljuki
Gregor Božič, 2005, izvirni znanstveni članek

Povzetek: Namen raziskave je bil preveriti sposobnost naravnega obnavljanja genetskega vira Picea abies (L.) Karst. na objektu stalne raziskovalne ploskve Šijec na Pokljuki, Slovenija. Genetsko strukturo zrelega sestoja smreke in genetsko strukturo naravnega mladja v razlino velikih pomladitvenih jedrih smo preuili z elektroforetsko analizo 15 polimorfnih izoencimskih genskih lokusov desetih encimskih sistemov (GDH, F-EST, GOT, IDH, LAP, MDH, PGI, PGM, SKDH, 6-PGDH). Pod doloenimi pogoji je bila genetska struktura 101 dreves naravnega pomladka in 64 dreves sestoja, iz katerega je nastal, popolnoma primerljiva. Obnova smrekovega sestoja z naravnim pomlajevanjem zagotavlja trajno ohranjanje genskega vira smreke in je v primeru vejih pomladitvenih jeder tudi zagotoviloza neprekinjeno ohranjanje njegove prilagoditvene sposobnosti.
Ključne besede: Picea abies (L.) Karst., naravno pomlajevanje, genetska struktura, izoencimi, ohranjanje gozdnih genskih virov, genski viri
Objavljeno v DiRROS: 12.07.2017; Ogledov: 2961; Prenosov: 1233
.pdf Celotno besedilo (180,64 KB)

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