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1.
Rast in kakovost metasekvoje (Metasequoia glyptostroboides Hu et Cheng) v živem arhivu pri Ljubljani
Iza Petek, Gregor Božič, Dušan Jurc, Maja Jurc, Kristjan Jarni, Robert Brus, 2022, izvirni znanstveni članek

Povzetek: Analizirali smo živi arhiv metasekvoje (Metasequoia glyptostroboides Hu et Cheng) na obrečnem rastišču ob Savi pri Ljubljani. Osnovan je bil v letih 1993 in 1994 s sadikami, vzgojenimi iz originalnih semen z območja na Kitajskem, kjer je bila vrsta opisana (klasično nahajališče oz. locus classicus). Drevesa v nasadu so bila prvič izmerjena spomladi leta 2000 in nato še leta 2006, spomladi v letu 2020 pa smo meritve ponovili. V starosti 30 let je povprečno drevo merilo v višino 20,7 m, povprečni premer koreninskega vratu na višini debla 0,1 m je znašal 72,3 cm, povprečni premer debla na prsni višini pa 51,4 cm. Ugotovili smo, da je pogostnost reproduktivnih organov, torej storžev in moških cvetov, povezana s premerom in višino drevesa. Užlebljenost debla je zelo variabilna in povezana s premerom, zelo variabilno je tudi zmanjšanje premera z višino. Povezave med omenjenimi znaki in lego drevesa v nasadu nismo ugotovili. Svetloba oziroma lega v nasadu ni edini dejavnik, ki vpliva na lastnosti posameznega drevesa, vzrok je tudi genetska variabilnost med drevesi.
Ključne besede: Metasequoia glyptostroboides, semenski nasad, rast, kakovost, Slovenija
Objavljeno v DiRROS: 11.08.2022; Ogledov: 3; Prenosov: 5
.pdf Celotno besedilo (694,92 KB)

2.
Good survival of broadleaf tree species in a four-year-old plantation in the Slovenian Karst
Nina Škrk, Kristjan Jarni, Robert Brus, 2022, izvirni znanstveni članek

Povzetek: Six broadleaf tree species (Celtis australis L. – Mediterranean hackberry, Quercus petraea (Matt.) Liebl. – sessile oak, Fagus sylvatica L. – European beech, Prunus avium L. – wild cherry, Juglans regia L. – Persian walnut and Acer pseudoplatanus L. – sycamore maple) were planted in 2012 in a trial in the Slovenian Karst on two sites differing in productivity to test their suitability for use in the conversion of old pine stands into ecologically more stable broadleaf forests and to investigate their possible response to the harsher growth conditions predicted in the future. The selected economically interesting tree species have higher timber quality than broadleaves which regenerate naturally (e.g., Ostrya carpinifolia, Fraxinus ornus, Quercus cerris). Measurements were taken in 2017, after four growth seasons. All planted species except Fagus sylvatica had a high survival rate. In total, 70% of all seedlings survived, which shows promising potential. The survival rate was higher at the site on flat terrain than at the site on a slope. Prunus avium was the most successful of all planted species in terms of survival rate, at 83%, and other measured parameters (height, height increment, stem diameter, vitality and quality), and Fagus sylvatica was the least successful, with a survival rate of only 20%. Celtis australis had the highest survival rate, at 87%. Acer pseudoplatanus had the largest differences in measured parameters between the more and less productive sites among all planted species. Quercus petraea showed high resistance to xeric conditions and is expected to be the most successful in conversions. All planted species except Fagus sylvatica show favourable initial potential for the future conversion of Karst pine forests.
Ključne besede: forest conversion, broadleaves, survival rate, seedlings quality, climate change
Objavljeno v DiRROS: 28.06.2022; Ogledov: 396; Prenosov: 171
.pdf Datoteka (3,13 MB)

3.
Biotic threats for 23 major non-native tree species in Europe
Elisabeth Pötzelsberger, Martin M. Gossner, Ludwig Beenken, Anna Gazda, Michal Petr, Tiina Ylioja, Nicola La Porta, Dimitrios N. Avtzis, Elodie Bay, Maarten De Groot, Kristjan Jarni, Nikica Ogris, Marjana Westergren, 2021, izvirni znanstveni članek

Povzetek: For non-native tree species with an origin outside of Europe a detailed compilation of enemy species including the severity of their attack is lacking up to now. We collected information on native and non-native species attacking non-native trees, i.e. type, extent and time of first observation of damage for 23 important non-native trees in 27 European countries. Our database includes about 2300 synthesised attack records (synthesised per biotic threat, tree and country) from over 800 species. Insects (49%) and fungi (45%) are the main observed biotic threats, but also arachnids, bacteria including phytoplasmas, mammals, nematodes, plants and viruses have been recorded. This information will be valuable to identify patterns and drivers of attacks, and trees with a lower current health risk to be considered for planting. In addition, our database will provide a baseline to which future impacts on non-native tree species could be compared with and thus will allow to analyse temporal trends of impacts.
Objavljeno v DiRROS: 21.02.2022; Ogledov: 163; Prenosov: 185
.pdf Celotno besedilo (1,60 MB)
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4.
Differences in growth and log quality of Douglas-Fir (Pseudotsuga menziesii (Mirb.) Franco) provenances
Peter Smolnikar, Robert Brus, Kristjan Jarni, 2021, izvirni znanstveni članek

Povzetek: Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is a non-native conifer from western North America that was introduced into European forests at the end of the 19th century. Plantations of Douglas-fir in Europe have shown good performance, quality, and resilience to exacerbating climatic conditions. However, all these qualities strongly depend on provenance. A total of 1061 surviving trees of fifteen different Douglas-fir provenances were measured in a Slovenian provenance trial that was established within the framework of the 1966/1967 IUFRO seed collection program. We found significant differences among provenances with respect to survival rate, growth performance, and log quality. The total recorded yield of the 46-year-old stand was 602.9 m3/ha, and the average survival rate was 43%. The correlation of juvenile tree heights in 1985 and their average breast height diameters in 2017 is positive and significant. Based on vitality and diameter, the best performing provenances were Yelm and Cathlamet. The provenance with the best log quality assessed through branchiness is Jefferson (Olympic Peninsula, western Washington). All the most promising provenances for western Slovenia (Central Europe) originate from the low-altitude western coast of Washington (WACO), with the Cathlamet provenance showing the best combination of good growth, survival rate, and log quality
Ključne besede: coniferous plantation, IUFRO provenance trial, non-native species, variability, growth, branching
Objavljeno v DiRROS: 05.03.2021; Ogledov: 601; Prenosov: 447
.pdf Celotno besedilo (510,73 KB)
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5.
Uspevanje omorike (Picea omorika (Pančić) Purk.) v generativnem semenskem nasadu Počivalnik pri Postojni
Sebastian Bambič, Kristjan Jarni, Gregor Božič, Robert Brus, 2020, izvirni znanstveni članek

Povzetek: Omorika (Picea omorika (Pančić) Purk.) je endemična drevesna vrsta z Balkanskega polotoka, ki dobro uspeva tudi v Sloveniji in bi bila na nekaterih rastiščih v manjših deležih lahko zanimiva alternativa navadni smreki (Picea abies (L.) Karst.). Raziskavo smo opravili v nasadu omorike pod vrhom hriba Počivalnik med Uncem in Postojno. Drevesa so bila posajena leta 1988 in so zdaj v fazi drogovnjaka. Izmerili smo jim prsni premer in ocenili zdravstveno stanje. Izračunali smo deleže dreves različnih zdravstvenih stanj za posamezne provenience in fenotipe, izdelali model nasada, napravili analizo variance in post hoc test. Ugotovili smo, da imajo provenience velik vpliv na vitalnost dreves, ne pa tudi na debelinski prirastek. Vitalnost dreves se prav tako razlikuje med posameznimi fenotipi. Korelacijo med fenotipi in prsnimi premeri smo potrdili pri dveh od petih fenotipov (B; tip 'semidichotomy', C; tip 'serbica'). Vpliv fenotipa na debelinski prirastek je v različnih proveniencah različen. Glede na našo raziskavo bi bil ob morebitni uporabi za Dinarski kras v Sloveniji najprimernejši semenski material provenience Šargan, najprimernejša fenotipa pa C (tip 'serbica') in F (tip 'argentea'), oba sicer najbolj zaželena tudi v hortikulturi.
Ključne besede: Picea omorika, provenienca, fenotip, vitalnost, ujma, pogozdovanje
Objavljeno v DiRROS: 18.11.2020; Ogledov: 2986; Prenosov: 956
URL Povezava na celotno besedilo
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6.
Fotografski natečaj
Robert Brus, Kristjan Jarni, 2019, drugi članki ali sestavki

Ključne besede: fotografski natečaji, razpis, gozdarstvo
Objavljeno v DiRROS: 08.08.2019; Ogledov: 1964; Prenosov: 495
.pdf Celotno besedilo (193,82 KB)

7.
Možnosti pridobivanja in uporabe gozdnega reprodukcijskega materiala navadnega koprivovca (Celtis australis L.) v Sloveniji
Kristjan Jarni, Nika Žgur, Filip Mehmedovič, Robert Brus, 2018, izvirni znanstveni članek

Povzetek: Navadni koprivovec (Celtis australis L.) je drevesna vrsta, značilna za mediteranske in toplejše submediteranske gozdove, kjer se pojavlja posamično ali v manjših skupinah. Ima izjemno kakovosten les, je prilagojen suši ter odporen proti boleznim, škodljivcem in onesnaženju. V preteklosti je bil pri gospodarjenju z gozdovi večinoma spregledana vrsta. V primeru, da bi ga v prihodnje želeli močneje vnašati v gozdove, bi le-to potekalo prek umetne obnove, za kar pa nimamo ustreznega gozdnega reprodukcijskega materiala kot tudi izkušenj z generativnim razmnoževanjem in vzgojo sadik. V raziskavi smo analizirali dva sestoja koprivovca pri Brestovici in Opatjem selu na Krasu. Analiza je pokazala, da velikost obeh sestojev in dobra prilagojenost lokalnim razmeram potrjujeta primernost, da sestoja uvrstimo med gozdne semenske objekte, večja pomanjkljivost je le številčno pomanjkanje dreves z odličnimi fenotipskimi lastnostmi. V prid odobritve govori tudi dejstvo, da boljših tovrstnih sestojev v Sloveniji nimamo. Rezultati kalivosti semena so v nadaljevanju pokazali, da je generativno razmnoževanje navadnega koprivovca razmeroma preprosto in da je najboljši način setev semena na prosto takoj po nabiranju, tj. v mesecu septembru, ko se plodovi črno-vijolično obarvajo. Visoka kalitev predhodno stratificiranega semena je dosežena tudi pri spomladanski setvi na prosto.
Ključne besede: seme, kalitev, semenski objekti, navadni koprivovec, gozdni reprodukcijski material
Objavljeno v DiRROS: 13.11.2018; Ogledov: 3273; Prenosov: 2322
.pdf Celotno besedilo (1,59 MB)
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8.
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: 3349; Prenosov: 2115
.pdf Celotno besedilo (1,78 MB)
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9.
Sexual dimorphism and distribution OF Daphne laureola L. in the Bohor area
Miha Jagrič, Kristjan Jarni, Robert Brus, 2013, izvirni znanstveni članek

Povzetek: Gynodioecious Daphne laureola L. is one of six species of the genus Daphne L. native to Slovenia. The main goals of this research were to determine the distribution of Daphne laureola in the Bohor area, the sexual structure of populations and its correlation with site conditions, and whether morphological differences exist between females and hermaphrodites beyond those of flower structure. Four research plots located on the north side of Bohor were selected - two in each altitude range. A total of 277 plants were studied to determine the sexual structure of the populations, 90 of which were additionally studied for sexual dimorphism. The species was recorded for the first time in quadrant 9959/1 of the Central European flora mapping grid, extending its previously known distribution. The share of female plants was between 3.17% and 47.17% and was lower at higher altitudes. The frequency of plants, morphological traits, and the proportion of female individuals are highly correlated with environmental factors. Plants bore more flowers at higher altitudes, and leaves were longer, with rounder tips and sharper bases.The majority of morphological differences between females and hermaphrodites were minor and not statistically significant.
Objavljeno v DiRROS: 12.07.2017; Ogledov: 3141; Prenosov: 1644
.pdf Celotno besedilo (834,27 KB)

10.
Analysis of the influece of ungulates on the regeneration of Dinaric fir-beech forests in the research site Trnovec in the Kočevje forest managementregion
Kristjan Jarni, Dušan Robič, Andrej Bončina, 2004, izvirni znanstveni članek

Povzetek: In the period 1970-2000, 152 fenced-in areas were built in the Kočevje Forest Management Region with an aim to protect tree seedlings and saplings from ungulatesć activity and to monitor the influence of roe and red deer on natural regeneration. The average surface area of fenced areas is 0.71 ha. Using the pair comparison technique (fenced vs. unfenced areas), the structureand the composition of the natural regeneration of tree species as well as complete shrub and herb vegetation were analysed in the research site Trnovec. Furthermore, the vegetation was investigated using the Braun-Blanquetmethod. The research results show significant differences between fenced and unfenced areas, both in tree species composition and in theheight structure of the sapling community. In fenced areas the total numberof saplings taller than 50 cm is higher and an increase is also evident in the number of saplings of silver fir Abies alba, sycamore Acer pseudoplatanus, elm Ulmus glabra and other minor tree species. There are also significant differences in species composition and in the abundance of plant species in the herb layer. The results show that natural regeneration of Dinaric fir-beech forests is successful, provided the influence of ungulates is excluded.
Ključne besede: natural forest regeneration, Fagus sylvatica, roe deer, fir-beech forest, Abies alba, fenced area, seedling browsing, Kočevje forest region, research site Trnovec
Objavljeno v DiRROS: 12.07.2017; Ogledov: 3096; Prenosov: 1328
.pdf Celotno besedilo (420,75 KB)

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