11. Resin yield of Pinus nigra and Pinus sylvestris in the Slovenian KarstDomen 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: 5026; Prenosov: 3293
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12. Sexual dimorphism and distribution OF Daphne laureola L. in the Bohor areaMiha 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: 4597; Prenosov: 2426
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13. Analysis of the influece of ungulates on the regeneration of Dinaric fir-beech forests in the research site Trnovec in the Kočevje forest managementregionKristjan 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: 4500; Prenosov: 2016
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14. Morphological variability of Fraxinus angustifolia Vahl in the north-western BalkansKristjan Jarni, Marjana Westergren, Hojka Kraigher, Robert Brus, 2011, izvirni znanstveni članek Povzetek: Fraxinus angustifolia Vahl is a species native in the north-western Balkans, where it has a divided range. Most of its range is
located in flood-prone riparian sites in the Pannonian plain but the species is also found on humid sites along some rivers in the
Submediterranean region. We analysed morphologic variation within and between five populations (14 trees/population) located in the Subpannonian and Submediterranean region of Slovenia. Thirty two characters were assessed on ca. 80 leaves from
each tree which were divided depending on exposure to sunlight (sun and shade leaves), and 8 traits on each fruit (ca. 50 fruits/
tree). A hierarchically designed experiment using analysis of variance confirmed the significant contribution of all the analysed
hierarchical levels of variation to the total variation. The results show that the differences between the trees in a single population are the greatest factor of variability of leaves, followed by differences between populations and differences which are the result of variation in exposure to sunlight. Leaves in shade positions are typically larger than those in sunny positions, and they
have broader and shorter-pointed leaflets; in this feature they are very similar to the leaves of F. excelsior. Stepwise discriminant
analysis showed that the traits which refer to the leaflet number and length are the best differentiating traits between individual populations. The Submediterranean population Dragonja stands out with the smallest leaves and the population Lijak from
the same region is the most similar to Dragonja for most morphological traits. In general, phenotypic differences between the
Subpannonian and the Submediterranean populations of F. angustifolia are minor and indistinct. Based on the differences ascertained by the study, we can only confirm the presence of F. angustifolia subsp. oxycarpa (Bieb. ex Willd.) Franco et Rocha Alfonso in this part of its natural range.
Objavljeno v DiRROS: 12.07.2017; Ogledov: 2875; Prenosov: 1316
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17. Izdelava registra plus dreves divje češnje (Prunus avium L.) v SlovenijiKristjan Jarni, Domen Gajšek, Gregor Božič, Hojka Kraigher, Robert Brus, 2017, izvirni znanstveni članek Povzetek: Divja češnja (Prunus avium L.) je zaradi ekološkega pomena in kakovostnega lesa za gojenje vse bolj zanimiva manjšinska drevesna vrsta, vendar je težavno zagotavljanje ustreznih količin njenega kakovostnega gozdnega reprodukcijskega materiala. S pomočjo Zavoda za gozdove Slovenije smo na območju vse Slovenije evidentirali 127 kandidatov za plus drevesa divje češnje. V drugem krogu smo na podlagi enotnega ocenjevanja znakov izbrali 107 fenotipsko najboljših dreves in jih bomo vključili v register plus dreves divje češnje. V register vključena drevesa bo mogoče uporabiti za izvedbo programa žlahtnjenja divje češnje in za osnovanje semenske plantaže, ki bo omogočala pridobivanje zadostnih količin genetsko izboljšanega gozdnega reprodukcijskega materiala. Register bo lahko služil tudi kot vzorčni primer še za druge manjšinske drevesne vrste.
Ključne besede: divja češnja, Prunus avium L., plus drevesa, semenska plantaža, gozdni reprodukcijski material, žlahtnjenje gozdnega drevja, Slovenija
Objavljeno v DiRROS: 22.06.2017; Ogledov: 4781; Prenosov: 881
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