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Query: "author" (Urša Vilhar) .

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30 let spremljanja stanja gozdov v Sloveniji
Gregor Božič, 2015

Keywords: gozdarstvo, elektronske knjige, monitoring gozdov
DiRROS - Published: 12.07.2017; Views: 2727; Downloads: 934
.pdf Fulltext (3,81 MB)

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Trace elements and nitrogen content in naturally growing moss Hypnum cupressiforme in urban and peri-urban forests of the Municipality of Ljubljana (Slovenia)
S. Berisha, Mitja Skudnik, Urša Vilhar, M. Saboljević, Saša Zavadlav, Zvonka Jeran, 2017

Abstract: We monitored trace metals and nitrogen using naturally growing moss Hypnum cupressiforme Hedw. in urban and peri-urban forests of the City Municipality of Ljubljana. The aim of this study was to explore the differences in atmospheric deposition of trace metals and nitrogen between urban and peri-urban forests. Samples were collected at a total of 44 sites in urban forests (forests within the motorway ring road) and peri-urban forests (forests outside the motorway ring road). Mosses collected in urban forests showed increased trace metal concentrations compared to samples collected from peri-urban forests. Higher values were significant for As, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Tl and V. Within the motorway ring road, the notable differences in element concentrations between the two urban forests were significant for Cr, Ni and Mo. Factor analysis showed three groups of elements, highlighting the contribution of traffic emissions, individual heating appliances and the resuspension of contaminated soils and dust as the main sources of trace elements in urban forests.
Keywords: heavy metals, biomonitoring, Ljubljana, ICP-MS, elemental analysis, factor analysis, traffic emissions
DiRROS - Published: 12.07.2017; Views: 2433; Downloads: 701
.pdf Fulltext (2,38 MB)

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Odvisnost med nastopom fenofaz pri bukvi in navadnem divjem kostanju v Kočevju ter povprečnimi mesečnimi temperaturami zraka v obdobju od leta 1961 do 1990
Urša Vilhar, Lučka Kajfež-Bogataj, 2003

Abstract: Analiza nastopa fenoloških faz gozdnega drevja in grmovja v dolgem časovnem nizu nam pojasnjuje odvisnost med časom pojavljanja določene fenofaze ter meteorološkimi razmerami. Na lokaciji Kočevje smo ugotavljali korelacijo med nastopom fenofaz za bukev (Fagus sylvatica L.) ter navadni divji kostanj (Aesculus hippocastanum L.) ter povprečnimi eno-, dvo- in tromesečnimi temperaturami zraka za obdobje od leta 1961 do 1990. Korelacije so tesnejše, če uporabimo povprečja temperatur dveh ali treh zaporednih mesecev. Največji delež pojasnjene variabilnosti pri bukvi smo dosegli z modelom za napoved začetka rumenenja listja (58 %). Kot prva pojasnjevalna spremenljivka se pojavlja povprečna temperatura v mesecih februarju, marcu in aprilu, kot drugapa povprečna temperatura mesecev julija, avgusta in septembra. Pri navadnem divjem kostanju smo največji delež pojasnjene variabilnosti dosegli zmodelom za napoved začetka splošnega cvetenja (65 %), na katero najbolj vplivajo povprečne temperature mesecev aprila in maja ter mesecev januarja, februarja in marca. Na splošno je začetek rumenenja listja pri bukvi dober kazalec temperaturnih razmer rastišča.
Keywords: fenologija, bukev, navadni divji kostanj, fenološka postaja Kočevje, temperatura zraka
DiRROS - Published: 12.07.2017; Views: 2854; Downloads: 1017
.pdf Fulltext (613,06 KB)

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Biodiversity of types of ectomycorrhizae in a norway spruce stands on Pokljuka
Urša Vilhar, Igor Smolej, Tadeja Trošt Sedej, Lado Kutnar, Hojka Kraigher, 2004

Abstract: Types of ectomycorrhizae were studied in soil cores from a young regeneration center in an autochthonous Norway spruce stand on Pokljuka (Triglav National Park, 1200 m.a.s.l.). Soil cores of equal volume (274 ml, 0 - 18 cm deep) weretaken from 33 sampling plots. In the samples all the roots were counted and types of ectomycorrhizae briefly characterized. From these data diversity indices (species diversity (d) and Shannon- Weaver index of diversity (H)) were calculated. Interactions among mycorrhizae, light regime and survival of spruce seedlings were studied. Out of about 50,000 root tips approximately 1 %were non-mycorrhizal, 63 % were old unviable mycorrhizae and 36 % were identifiable ectomycorrhizal root tips, forming 27 different types of ectomycorrhizae. Sixteen types of ectomycorrhizae were briefly characterized. The Shannon diversity index for types of ectomycorrhizae was high (3.13) with respect to the above-ground diversity of vegetation (1.7). The direct site factor was shown to be negatively correlated to ~Piceirhiza cornuta. The diffuse site factor was negatively correlated to Cortinarius sp. (obtusus type) and positively correlated to Inocybe sp. The ground vegetation cover waspositively correlated to Piceirhiza gelatinosa and the total vegetation cover to Elaphomyces sp.
Keywords: ectomycorrhizae, types of ectomycorrhizae, Norway spruce, natural regeneration, Pokljuka
DiRROS - Published: 12.07.2017; Views: 2577; Downloads: 932
.pdf Fulltext (1,79 MB)

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