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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: 1114; Prenosov: 380
Celotno besedilo (1,42 MB)
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Ključne besede: piezometri, hidrološki monitoring, Ljubljansko barje, mokrišče, podnebne spremembe, blaženje, raba zemljišč, sprememba rabe zemljišč, toplogredni plini
Objavljeno v DiRROS: 14.12.2020; Ogledov: 1162; Prenosov: 399
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Ključne besede: biogospodarstvo, raba lesa, kaskadna raba, tokovi lesa, krožno gospodarstvo
Objavljeno v DiRROS: 11.12.2020; Ogledov: 1219; Prenosov: 358
Celotno besedilo (425,22 KB)

Ključne besede: Poplar, Willow, Black Walnut, Black Locust, international commission, FAO, national report, questionnaire, genetics, forest protection, legislation, categorisation, forest products, ecology, Slovenia
Objavljeno v DiRROS: 11.12.2020; Ogledov: 1299; Prenosov: 409
Celotno besedilo (147,28 KB)

Povzetek: Invasive alien species (IAS) are an important threat to forests. One of the best ways to manage potential IAS is through early detection and rapid response (EDRR) strategies. However, when dealing with IAS in forests, EU regulations are divided between phytosanitary regulations and IAS regulations. A version of EDRR for the former has been in place in the EU for more than 15 years while the latter is still in the process of being implemented. During 2019, a workshop was held to gather international experts on different plant health pests and IAS. The purpose of this workshop was to identify the opportunities and difficulties in applying the EDRR system in the EU phytosanitary and IAS legislation to four species for providing suggestions to improve the EDRR system. The model species are well known and come from different trophic levels. These species were the American pokeweed (Phytolacca americana), the grey squirrel (Sciurus carolinensis); and the plant health pests Geosmithia morbida and Emerald ash borer (Agrilus planipennis). We identified the similarities in the challenges of early detection, rapid response and communication of these species. For all species, difficulties in species identification, knowledge gaps on the pathways of spread, a lack of resources and uncertainty over which national government service was the competent authority were identified as the main challenges. Other challenges like public perception for the grey squirrel or methodological problems were species-specific. Regarding the rapid response: public perception, determination of the eradication area, sufficient scientific capacity and the lack of resources were common challenges for all species. Therefore, collaboration between institutes dealing with plant health pests and IAS can lead to better control of both groups of unwanted %organisms in forests.
Ključne besede: early warning system, plant health legislation, EU IAS legislation, alien species, Geosmithia morbida, Emerald ash borer, American pokeweed, Grey squirrel, rapid response system
Objavljeno v DiRROS: 11.12.2020; Ogledov: 1607; Prenosov: 595
Celotno besedilo (995,71 KB)
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