1721 research outputs found
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Optimization of energy consumption and costs of wood drying with use of different drying techniques
No full textDolgotrajnost in energijska potratnost sušenja lesa povečuje tudi stroške, ki so med največjimi med lesnopredelovalnimi postopki. Analiza stroškov zahteva vsestransko obravnavo z vrednotenjem stroškov investicije, energije in dela kot tudi upoštevanje razvrednotenja zaradi napak ali dodane vrednosti kakovostnega osušenega lesa. V raziskavi smo nadgradili računalniški model sušilnega procesa z ekonomskim vrednotenjem različnih sušilnih tehnik. S primerjavo stroškov različnih sušilnih postopkov smo predpostaviti prehodno vlažnost lesa, pri kateri bi s kombinacijo več načinov sušenja dosegli najboljše ekonomske rezultate. Metoda je bila preverjena na sušenju bukovine debeline 38 mm s kombinacijo sušenja na prostem in komorskega sušenja. V zimskih mesecih je sušenje na prostem smotrno do vlažnosti 40 %, v najugodnejših klimatskih razmerah pa je optimalna vlažnost prehoda iz sušenja na prostem v komorsko sušenje 23 %. Predstavljeno metodo je mogoče uporabiti tudi za optimizacijo različnih tehničnih postopkov sušenja lesa
Dendrochronological dating of rural buildings in Sevno, Slovenija
No full textThe owners of the Matičkova farm (Sevno, Slovenia) intended to reconstruct the house and the pigsty in agreement with their original appearance. Knowledge on the age and history of the buildings and the timber used for constructions would help to do this. For this purpose 62 samples of wood were taken from the constructions and wood identification and dendrochronological dating were done in accordance with standard methods. The structures have been made of oak (Quercus spp.), sweet chestnut (Castanea sativa), beech (Fagus sylvatica), alder (Alnus glutinosa), birch (Betula pendula), willow (Salix spp.), and Scots pine (Pinus sylvestris). 18 samples of oak, one sample of chestnut and one sample of beech have been dendrochronologically dated. Based on the end dates of different timber elements we assumed that the
house was most likely built at the end of 1877 or soon after that. The pigsty was built after 1927. In both objects we could determine when the repairs or reconstructions of the structures took place. In the project was involved a group of students of the Department of Wood Science and Technology
Effects of heterospecific and conspecific vibrational signal overlap and signal-to-noise ratio on male responsiveness in Nezara viridula (L.)
No full textAnimals often communicate in environments with high levels of biotic noise that arises from the signals of other individuals.
Although effects of background biotic noise on mate recognition and discrimination have been widely studied in air-born sound
communication, little is known about incidental interference between signallers that use substrate-borne vibrational signals. In
this study we investigated the ability of males of the southern green stink bug Nezara viridula (L.) (Heteroptera: Pentatomidae) to
recognize conspecific female song in the presence of biotic noise originating from conspecific and heterospecific vibrational
signals. We tested male responsiveness on a bean plant in playback experiments. One leaf was vibrated with conspecific female
song, while to the other one we simultaneously applied either heterospecific female signal or various altered conspecific signals
with different temporal parameters. We tested males in three levels of biotic noise, ranging from +6dB to –6dB and we compared
male responsiveness in each treatment with response obtained in unilateral treatment with unaltered conspecific female calling
song. Male responsiveness was reduced in the presence of heterospecific signals or when background noise from conspecific
signals obscured the species-specific temporal pattern of conspecific female song. By contrast, the presence of two sources of
conspecific female songs had a positive effect on male responsiveness, for as long as the signal repetition rate of perceived song
did not differ from the species-specific value. In the presence of interfering background signals, searching activity was less
affected than male signalling. Increased signal-to-noise ratio restored male responsiveness to the level expressed in unilateral
stimulation with conspecific female song. The results are discussed with regard to male behavioural strategies for vibrational
communication in a noisy environment
Review of faecal pellet-group count methods for estimating deer numbers
Get PDFKnowledge of abundance and local densities of deer populations is important inmanagement as well as in biological context. Faecal pellet-group count method, widely used around the world for estimating deer numbers, has been almost neglected in our country. Therefore, we have prepared a comprehensive overview of the method with recommendations for Slovenia to enhance its use. In principle, there are two ways to perform the faecal pellet-group count method, i.e. clearance plot and standing crop method. The latter is not recommended in a daily management practice, as it requires faecal pellet-groupdecay rate estimation, which is rather season and microhabitat specific. Sampling can be done on sampling plots of different shapes and sizesor with the line transect method. Sampling design depends on expected deer densities and ground cover dependent pellet-group detectability. Since distinct habitats are used differentially by the deer, study area stratification on specific habitat types regarding the expected deer densitiesis recommended. Within the species, defecation rates (i.e. number of pellet-groups per day) vary according to season, animal age and gender; nevertheless, due to comparative reasons we recommend the use of constant defecation rates (i.e. 25 for the red deer, 20 for the roe deer, respectively). Moreover, multiple samplings are needed to cover seasonal variety in habitat use. Sampling design is of a major importance for the success of the method and has the biggest impact on the precision of deer numbers/densities estimates, therefore much effort should be devoted to this stage
Phytoremediation of metal contaminated soil with the use of tree seedlings
No full textPhytoremediation was performed on two research plots at Poček military training ground. The first research plot (polluted with Pb
and Cu) is situated at the shooting range and the second in its close vicinity, where soil is less loaded with metals. Seedlings of five
species (Alnus glutinosa L., Acer pseudoplatanus L., Betula pendula Roth., Pinus sylvestris L., Salix caprea L.) were planted on plots
according to the standardised system; in addition, growth parameters and metal contents in roots, stems and shoots were measured as
well. Although seedlings accumulate only Cd (BCF = 1.2) in their roots, and the rest of metals are taken up in smaller concentration
and species specific, the majority of tree species have the potential for remediation and especially for phytostabilisation. Favourable
ratio between bioaccumulation and translocation was determined for all species with the exception of Salix caprea, which was effective
in taking up Cd in leaves (TF = 6.9). The results of our study have shown that Pinus sylvestris is the most suitable species regarding
growth parameters and metal uptake, whereas the least suitable is Salix caprea
V sortno listo Republike Slovenije se vpiše sorta krompirja (Solanum tuberosum L.), z odobrenim imenom KIS Kokra, registrska številka sorte SOT194
Get PDFScat analysis of gray wolves (Canis lupus) in Slovenia
Get PDFGray wolf (Canis lupus) is an opportunistic predator, hunting mainly large mammals. Its diet varies substantially between different regions; it is necessary, therefore, to obtain reliable data from different parts of the wolf's range. In Slovenia, the wolf's diet has been poorly studied. In the present preliminary analysis, we analyzed 30 wolf scats collected throughout the wolf range in the country. We determined prey species using microscopic analysis of ground hairs and inspection of teeth and postcranial skeletal remains. For each prey group we calculated the frequency of occurrence and estimated the consumed biomass. In Slovenia, the wolf's main prey are cervids (Cervidae), which were found in 87% of samples and represented 85% of consumed biomass. To a lesser extent, wolves were feeding on young wild boar (Sus scrofa; 7% of scats, 5% of consumed biomass) and on remains of domestic animals (7% of scats, 10% of consumed biomass)
Osmotic component of water potential and stress adaption of adult Pedunculate oaks (Quercus robur L.) in stands with different tree density
No full textPressure volume curves were applied to define differences in stress adaptation between two managed forest complexes and virgin forest remnant; in Murska šuma, Krakovo forest and Krakovo old growth forest. Species response between adult stands after stronger thinning and comparable stand without any silvicultural measures within same forest complex was compared in two consecutive years, 2003 and 2004. Significant differences in osmotic potential (full turgor) component for plots in Murska šuma in 2003 as well as in Krakovo forest between managed forest and old growth-forest were confirmed. In all cases, values became more negative, indicating slight capability of oaks to adapt with increasing drought stress. Reaction/stress adaptation of forests after thinning indicated well adapted mechanism to address drought stress in spite of the age. We may connect such improved drought response with increased individual space for growth and lower stand density