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1194. Red deer (Cervus elaphus) bark stripping on spruce with regard to spatial distribution of supplemental feeding placesKlemen Jerina, Mihec Dajčman, Miha Adamič, 2008, original scientific article Abstract: Forest damages caused by red deer and some other large herbivore species occasionally feeding on tree bark, are a grave ecological and economic problem in many parts of the world. Winter supplemental feeding is commonly used to mitigate the problem, but its effects are poorly known. This study, carried out at Pohorje (Slovenia) and including over 2,300 trees, used binary logistic regression to analyse the effects of supplemental feeding and many other factors on the probability of bark stripping on spruce. The probability of bark stripping depends on distance from the forest edge, density, age and tree species diversity of stands, slope and aspect of terrain, and red deer density; contrary to expectations, it is not related to distance from feeding places. As much as 35% of spruce trees were damaged. The damage was the highest in younger, denser pure spruce stands, whose favourable protective and microclimatic conditions (thinner snow cover, higher effective temperatures) make them a preferred winter habitat for red deer. They contain,however, little other food but bark. To prevent / diminish bark stripping we propose a stronger thinning of such stands. Supplemental feeding may reduce damage only in exceptional cases, when animals are lured and concentrated in less sensitive areas, but in general we advise against the use of this measure due to its other negative effects.
Keywords: red deer, Cervus elaphus, bark stripping, Norway spruce, Picea abies, forest damages, supplemental feeding, Slovenia, environmental factors
Published in DiRROS: 12.07.2017; Views: 4337; Downloads: 1948
 Full text (597,09 KB) |
1195. Dinamika ksilogeneze pri gradnu v letu 2007Jožica Gričar, 2008, original scientific article Abstract: S svetlobnim mikroskopom smo raziskali sezonsko dinamiko nastanka lesa pri gradnu (Quercus sessiliflora Salisb.) v rastni sezoni 2007. Konec marca so se delitve v kambiju že začele in število celic je naraslo na 10-11 slojev. Maksimalno celično produkcijo smo na ksilemski strani zabeležili v drugi polovici maja, ko smo ugotovili prek 100 ?m prirastka na teden. Kambijeva aktivnost se je zaključila do sredine avgusta in število celic je upadlo na 5-7 slojev. Oblikovanje sekundarne stene in lignifikacija v terminalnih celicah kasnega lesa pa sta potekala še nadaljnjih 4-5 tednov. Dinamika nastanka lesa pri gradnu se razlikuje od debelinske rasti iglavcev.
Keywords: Quercus sessiliflora, ksilogeneza, kambijeva aktivnost, traheja, rani les, kasni les
Published in DiRROS: 12.07.2017; Views: 4468; Downloads: 1933
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1196. Polifenoli v različnih vrstah macesna (Larix spp.)Janja Zule, Gašper Kozjan, 2008, review article Abstract: V članku so predstavljene različne vrste polifenolnih spojin, kot so npr. lignani, oligolignani in flavonoidi, ki jih najdemo v tkivih macesnov, to je dreves iz rodu Larix. Opisana je njihova biosinteza, kemijska struktura in lastnosti, med katerimi je poudarjen predvsem njihov antioksidativni potencial. Predstavljene so metode kvantitativne izolacije iz drevesnih tkiv in kemijske karakterizacije z uporabo sodobnih kromatografskih analiznih tehnik. Raziskave so pokazale, da so največje koncentracije lignanov in flavonoidov v grčah, vejah in skorji dreves. Najpomembnejši med flavonoidi v tkivih macesnov je taksifolin. Glavni predstavnik lignanov, ki jih bomo našli predvsem v grčah, je sekoizolaricirezinol, poleg njega pa sta zastopana tudi laricirezinol in ciklolaricirezinol. Polifenoli so ključnega pomena za obstojnost lesa, saj pomenijo učinkovito kemijsko zaščito pred različnimi okužbami. Zaradi visokih koncentracij bioaktivnih lignanov v grčah iglavcev bi slednje lahko rabile kot vir za tehnološko pridobivanje teh dragocenih komponent.
Keywords: macesen, Larix spp., polifenoli, lignani, oligolignani, flavonoidi, obstojnost lesa, antioksidativne lastnosti, kemijska karakterizacija
Published in DiRROS: 12.07.2017; Views: 4669; Downloads: 1910
Full text (646,56 KB) |
1197. Windstorm restoration efficiency using the Kidričevo windstorm (29 June, 2006) as a case studyGoran Paulinič, Janez Krč, 2008, original scientific article Abstract: Economic efficiency is one of the many essential demands regarding the technical management of windstorms. The main goal of this paper is to analyze a hypothetical scenario in which a forest owner works independently on windstorm restoration, using his own equipment and work power. Managing windstorm damage is a difficult and dangerous task, although a potentially lucrative endeavour as our investigation shows. A windstorm represents an opportunity for instant profit for forest owners who are independent of regular forest income. Economic damage is greater and longer lasting for owners with large forest properties and for farm households, which depend on regular forest income. We compared two potential scenarios in a wind-damaged area within the 2000-2010 forestry management period. First, we include a hypothetical scenario in which the windstorm did not occur. An inventory of regular thinning as well as simulation of future events based on past dynamics was done. We also performed a second scenario in which we assumed that private owners carry out windstorm restoration alone, although in reality felling has been carried out with short-wood technology (mechanized cutting). The results section presents the possibilities to attain reasonably high yield by dealing with the consequences of a minor windstorm.
Keywords: cost analysis, production effects, scenarios, windstorm, storm damage, forest
Published in DiRROS: 12.07.2017; Views: 3879; Downloads: 1821
Full text (624,35 KB) |
1198. Legal basis, standards and criteria for evaluating thermal conditions in forest workAnton Poje, Igor Potočnik, 2008, review article Abstract: In this discourse, the Slovene legal basis for thermal conditions at work, together with three international standards for studying thermal conditions SIST EN ISO 7730 (Thermal comfort), SIST EN 27243 (hot environments) and SIST EN ISO 11079 (cold environments), are presented. All three international standards list the criteria for evaluation of thermal conditions and represent the scientific research basis for studying work in practice. For efficient work safety, knowledge of the national legislation is implicit.
Keywords: international standards, working conditions, thermal conditions, legislation
Published in DiRROS: 12.07.2017; Views: 4441; Downloads: 1859
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1199. Assessing maximum loads when skidding wood uphill with tractorsBoštjan Košir, Jurij Marenče, 2008, original scientific article Abstract: The results of measuring maximum loads on different slopes when skidding uphill with WOO DY 110 cable skidder and adapted 4WD agricultural tractor AGT 835 are described in the article. Both tractors are very different and were chosen for the purpose of finding the limits of uphill skidding. Besides the slope, the pre-designated loads of different sizes and log orientation (butt-end or top-end forward) have been main variables. The trial was conducted on two concave shaped test skid trails in the forest. On the lower altitudes, the skid trails had small inclination, which slowly increased to 42% on the track where WOODY 110 was tested, and 27% where AGT 835 was measured. First the loads were skidded uphill with butt-end and then with top-end forward. The purpose was to choose too heavy loads, as we wished to stop tractors due to overload, but on different slopes. The proper load formation (butt-end forward if possible) in uphill skidding is most important on steeper skid trails. The dependency between maximum load and slope is linear. The calculated theoretical maximum load on horizontal surface enables us to make similar assessment for any other tractor weighing between 2 and 7 tons. For this purpose, John Deere 6220 and LIMB 80 LUXS adapted agricultural tractors for forest use were chosen and compared. The ratio between the tractor load on different slopes and tractor weight was calculated for all four tractors included in our comparison. Apart from the weight, tractor's engine torque (power) has the decisive influence on the load size. Maximum loads on different slope categories were calculated according to different engine powers.
Keywords: tractor, skidding wood, maximum slope, maximum load
Published in DiRROS: 12.07.2017; Views: 4304; Downloads: 1811
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1200. Analiza informacijskih vrzeli podatkov gozdne inventure v Sloveniji v luči zahtev Ministrske konference o varstvu gozdov v Evropi (MCPFE)Anže Japelj, Milan Hočevar, 2008, professional article Abstract: V okviru evropskega procesa MCPFE se stanje gozdov in trajnost gospodarjenja znjimi preverja na podlagi stanja ter sprememb šestih Helsinških meril in podrejenih kazalnikov trajnostnega gospodarjenja. Opredelili smo razhajanja - informacijske vrzeli - med informacijskimi zahtevami količinskih kazalnikov MCPFE in razpoložljivimi podatki gozdne inventure. Vrzeli smo opredelili na podlagi sedmih kakovostnih meril. Največji informacijski vrzeli smo z vidika podajanja stanja kazalnikov opredelili v okviru 3., z vidika sprememb pa 4. Helsinškega merila. Glavna vzroka za to sta, da gozdna inventura ne daje nikakršnih podatkov za dva kazalnika 3. in en kazalnik 4. Helsinškega merila, ter dejstvo, da podatki velikokrat obstajajo le za eno obdobje. Vrzelim botrujejo tudi neusklajenost definicij, prostorska nepopolnost podatkov in nepreglednost metodologij. Za zmanjšanje informacijskih vrzeli bi bilo treba vsisteme zbiranja podatkov vpeljati nove znake (npr. gozdni tipi, enodobni/raznodobni sestoji, tipi obnove), postopki bi morali temeljiti na jasnih statističnih načelih, ki jih je treba dokumentirati.
Keywords: MCPFE, gozdna inventura, gozdna statistika, informacijske vrzeli, trajnost, gospodarjenje z gozdovi
Published in DiRROS: 12.07.2017; Views: 4596; Downloads: 1945
Full text (462,90 KB) |
