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Keywords: tujerodne drevesne vrste, Alpe, invazivne drevesne vrste
Published in DiRROS: 12.08.2022; Views: 104; Downloads: 33
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Abstract: 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.
Keywords: Metasequoia glyptostroboides, semenski nasad, rast, kakovost, Slovenija
Published in DiRROS: 11.08.2022; Views: 113; Downloads: 35
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Abstract: Riparian forests are among the most diverse terrestrial ecosystems, yet their biodiversity is increasingly threatened by habitat degradation, climate change, river regulation and invasive species. We investigated deadwood, widely recognized as an indicator for forest biodiversity, in riparian forests of the Mura-Drava-Danube Transboundary Biosphere Reserve. The Biosphere Reserve is a conservation area that spans five countries and three rivers located in south-eastern Europe. In detail, we analyzed the drivers of lying deadwood volume, occurrence and decay related to floodplain type, silvicultural management, and climatic conditions using regression models. Lying deadwood occurrence and volume significantly decreased as distance from the river edge increased, indicating that river dynamics likely play a role in deadwood accumulation in riparian forests. Deadwood volume was also positively influenced by stand basal area, a parameter that can be directly addressed by silvicultural management. Deadwood decay was affected positively by temperature and negatively by precipitation, highlighting the importance of climatic conditions on decay progression. However, in order to draw more accurate conclusions about the drivers and dynamics of deadwood in riparian forests, further monitoring efforts that consider river flooding and flow regime, deadwood transport and saproxylic organism activity in addition to forest management and site conditions, are needed.
Keywords: alluvial forest, hardwood floodplain, deadwood decay, Mura-Drava-Danube transboundary biosphere, reserve, riparian area, softwood floodplain, UNESCO biosphere reserve, wetlands
Published in DiRROS: 18.07.2022; Views: 105; Downloads: 79
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Abstract: Provenance trials are a valuable source of information, especially in species such as European beech (Fagus sylvatica L.), which will likely increase its distribution due to global warming. The current study compares radial increment and wood density of beech provenances in the juvenile development stage from contrasting environments in Europe (Belgium, Slovenia, Czech Republic, Italy) planted at a mesic to wet site in Slovenia and a xeric site in Hungary. Existing data (past measurements of diameters and height) were combined with new measurements of tree height, diameter, dendrochronological and resistance drilling density measurements to assess differences in provenance radial growth. The wood density data were evaluated using a Bayesian general linear model. In order to study the differences in radial increment in more detail, two weather-wise contrasting years (2014 and 2017) were selected from the last decade, based on calculations of the 12-month Standardized Precipitation-Evapotranspiration Index. The differences in average tree-ring width among provenances at each sampled site appeared to be relatively small when averaged over a whole decade of data. However, according to year-to-year data, some provenances grew faster than others, especially in favorable weather conditions. In unfavorable conditions, the differences in tree-ring widths among provenances were smaller. For most provenances, variation in tree-ring widths within the same provenance increased in unfavorable conditions. The difference between the provenances with the highest and lowest wood densities at both locations did not exceed 5%. The model results indicate that the Idrija (Slovenia) provenance probably has a higher median wood density than other studied provenances at both sites. Although the current study confirmed some differences in wood density between provenances and trial locations, the differences are negligible in practice due to their low magnitude and the fact that the analyzed trees were still juvenile. As beech has a diffuse-porous wood, negligible differences in wood density would also be expected in adult trees. Beech provenances for planting in relation to changing weather should probably be chosen for their ability to survive more extreme weather events rather than to improve radial increment or wood density, especially as the differences in wood density of juvenile trees are relatively small.
Keywords: Fagus sylvatica, tree-ring width, common garden, resistance drilling
Published in DiRROS: 15.04.2022; Views: 161; Downloads: 218
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Keywords: sadnja, setev, obnova gozdov, ocena uspešnosti
Published in DiRROS: 17.01.2022; Views: 336; Downloads: 0
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