An analytical model of layered continuous beams with partial interaction

Starting with the geometrically non-linear formulation and the subsequent linearization, this paper presents a consistent formulation of the exact mechanical analysis of geometrically and materially linear three-layer continuous planar beams. Each layer of the beam is described by the geometrically linear beam theory. Constitutive laws of layer materials and relationships between interlayer slips and shear stresses at the interface are assumed to be linear elastic. The formulation is first applied in the analysis of a three-layer simply supported beam. The results are compared to those of Goodman and Popov (1968) and to those obtained from the formulation of the European code for timber structures, Eurocode 5 (1993). Comparisons show that the present and the Goodman and Popov (1968) results agree completely, while the Eurocode 5 (1993) results differ to a certain degree. Next, the analytical solution is used in formulating a general procedure for the analysis of layered continuous beams. The applications show the qualitative and quantitative effects of the layer and the interlayer slip stiffnesses on internal forces, stresses and deflections of composite continuous beams

Preservation of forest soil and vegetation in the Capercaillie (Tetrao urogallus L.) habitat within the eastern Karavanke region an the eastern Kamnik-Savinja Alps in Slovenia

V študiji smo preuevali talne in vegetacijske razmere na devetih reprezentativnih ploskvah v habitatu divjega petelina (Tetrao urogallus L.) v visokogorju vzhodnih Karavank in vzhodnih Kamniško-Savinjskih Alp. Raziskave so potekale na ploskvah v razlinih gozdovih na rastiših divjega petelina, ki so bile sistematino izbrane glede na geološko podlago, ekspozicijo in stopnjo ohranjenosti gozdov. V drugotnih smrekovjih, ki so nastali na zarašenih pašnikih in porašajo distrina rjava tla na andezitnih grohih in na gnajsih, smo v primerjavi talnih lastnosti z dobro ohranjenim bukovimi gozdovi na podobnih rastiših zasledili znake degradacijskih procesov. V gozdovih na apnencih in dolomitih je bila rastlinska vrstna pestrost mnogo veja kot v gozdovih na nekarbonatnih kamninah. Floristina sestava in struktura vegetacijesta jasno nakazala stopnjo ohranjenosti oz. spremenjenosti gozdov tako na karbonatni kot tudi nekarbonatni matini podlagi.In the high-montane zone of the eastern Karavanke range and the eastern Kamnik-Savinja Alps of Slovenia, the soil and vegetation conditions on nine representative plots in the Capercaillie (Tetrao urogallus L.) habitat were studied. The research was carried out on plots in different forest types within the Capercaillie leks, selected with regard to the different bedrock, exposure and level of forest degradation. By contrast to the well preserved beech forest, degradation processes in dystric soil on andesite tuff and gneiss of secondary spruce forest in the abandoned pastures were detected. In the forests on limestone and dolomite, the plant species diversity is much higher than in the forests on non-carbonate bedrock. On carbonate and non-carbonate bedrock, too, the level of preservation of forests (secondary forest in pastures vs. co-natural forests on permanent forest land) is significantly reflected in the floristic composition and vegetation structure

Vegetation requirements of the black grouse habitat (Tetrao Tetrix L.) in Pohorje MTS.

Ruševec se na Pohorju (severno-vzhodna Slovenija) pojavlja na grebenskih legahv zahodnem delu pogorja. V rastitvenih sezonah 2000 in 2001 smo napravilipopis aktivnosti sub-populacij na šestih znanih rastiščih in tako izločili ploskve potencialnega habitata. Na njih smo raziskovali odločilne vegetacijske strukture. V primerjavo sta vključeni tudi dve opuščeni rastišči.Vse popisne ploskve (400x400m) so bile razdeljene na 256 osnovnih ploskvic. Ugotavljamo, da so štiri aktivna rastišča. med seboj relativno homogena, od njih pa se jasno ločita obe opuščeni rastišči. Razlike med srednjimi vrednostmi ocenjevanih značilnosti vegetacijskih tipov (pokrovnost borovnice, brusnice, jesenske vrese, zeliščne plasti, delež travišč in traviščv zaraščanju, grmovne plasti, sklep krošenj smreke in jerebike v drevesni plasti ter mravljišč) so statistično značilne. Trend upadanja abundance ocenjevanih značilnosti habitata je opazen od zahoda do opuščenih rastišč na vzhodu, od zaledja stabilne alpske populacije proti robu ob subpanonskem fitogeografskem območju. Pokrovnost borovnice na aktivnih rastiščih je 19%, na opuščenih 5%, pokrovnost zeliščne plasti ocenjevanih vrstje 38%, na opuščenih 11%, število mravljišč je 13,7/ha, na opuščenih rastiščih 8/ha. Primerjava med vegetacijskimi tipi je pokazala, da so najprimernejši habitati na mestih, kjer se prepletajo barjanski ekosistemi (12%), travišča (15%), zaraščajoča travišča (41 %), gozd (31 %) in vodne površine (1 %), vendar ob pogoju, da območje ni v nadaljnjem zaraščanju in ni preveč obljudeno.The Black Grouse inhabits mountain ridges in the western part of the Pohorje Mts (1543 m a.s.l., NE Slovenia). In the mating periods (2000, 2001), we carried out a survey of six known pairing areas and thus separated plots of potential habitat. In comparison, two abandoned display grounds were also incorporated. The base sampling areas (400 x 400 m) were divided into 256 square planes. It was discovered that the four active display grounds were relatively homogenous, while the two abandoned grounds clearly differed from them. The differences of the observed vegetation type characteristics (cover of blueberry, cranberry, autumn heather, herb layer, share of pastures including those now being overgrown, the abundance of bush layer, crown density of Norway spruce, mountain ash and anthills) are statistically significant. This declining tendency was noticeable from the display grounds in the west to the abandoned display grounds in the east, from the hinterland of a stable Alpine population towards the edge of the sub-Pannonian phytogeographic region. Cover value of blueberry on active display grounds is 19%, abandoned display grounds 5 %, herb layer 38% (11%), the number of anthills is 13.7/ha (8/ha). A comparison between vegetation types and richness of herbal and shrub layer has shown that the most suitable habitats for the Black Grouse are places with interchanging swampland ecosystems (12%),pastures (15%), partially overgrown pastures (41%), forest (31%) and water areas (1%), although on preliminary condition that the area is not beingfurther overgrown and overpopulated, by human

Uznemiravanje i predacija tetrijeba na pjevalištima u Alpskom i Dinarskom prostoru

Capercaillie (Tetrao urogallusL.) populations in central and south-east Europe cover fragmented edge habitats and are recorded to decline since 1960ies. Capercaillie leks in Slovenia are present at the south-eastern edge of the Alpine metapopulation and at north-western edge of Dinaric. These populations were monitored at leks in two periods in 1980 (466 monito red leks) and 2000 (599). All leks were monitored by local specialists (hunters and/or foresters) and main causes of observed lek populations decline were addressed to each endangered lek. Special emphasis was given to predation at leks, as suggested by D. Jenkins (2008). The six named reasons in 1980ies af fected 39 leks with logging of old-growth forests (at 71.8% of leks) and con struction of forest roads (7.7%) as most pronounced. In 2000 nine reasons affected 92 leks: (i) mountain tourism (26.1%), (ii) cutting of old-growth fo rests (19.60%), (iii) predators attacks (18.5%), (iv) forest management in spring time (9.8%), (v) pastures of livestock with wire fences in forests (6.5%), (vi and vii) berries picking and overgrowing the last pastures in forest-land scape, (viii) constructions of forest roads and (ix) infrastructure. The most profound change in reasons between 1980 and 2000 mapping data were: pre dation at leks, mountain tourism development, increasing of forest manage ment in spring time, wild pasturage of cattle and sheep in forests, overgrowing the last pastures in forest-landscape. A comparison of the increasing percen tage of leks endangered by predators since 1980 has shown positive correla tions with increasing of the main predator populations’ densities. Population density of martens (Martessp.) and wild boar (Sus scrofa) increased for 150% since 1980, while red fox (Vulpes vulpes) density increased only after 1990. Our results confirmed the assessment of reasons for threats to leks based on descriptions and experiences of observers as a suitable approach for caper caillie habitat risk assessment. Results for past decline and differences regar ding to the negative impacts on lek habitats are important guidelines for foresters and wildlife managers concerning sustainable forest management and maintenance of capercaillie populations.Populacije tetrijeba (Tetrao urogallusL.) u središnjoj i jugois toč noj Europi obuhvaća fragmentirani rub staništa,. Brojnost je u opadanju još od 1960. Staništa (pjevališta) tetrijeba u Sloveniji prisutna su na jugois toč nom rubu alpske metapopulacije i na sjeverozapadnom rubu dinarske me tapopulacije. Te populacije praćene su na pjevalištima u dva razdoblja, u 1980. g. (466 praćenih lokaliteta) i 2000. g. (599). Svi lokaliteti pratili su lo kalni stručnjaci (lovci i / ili šumari). Promatrali su glavne uzroke pada popu lacija u staništima, koje su utvrdili za svaki ugroženi lokalitet. Poseban na glasak istraživanja bila je predacija staništa, kao što je predložio D. Jen kins (2008). Glavni razlozi (od šest) ugrožavanja pjevališta (39 pjevališta) u 1980. g. bili su: sječa starih šuma (na 71,8 % lokaliteta) i izgradnje šumskih cesta (7,7 %) i branja šumskih plodova (7,7 %), dok je u 2000. g. bilo devet razloga na 92 ugrožena lokaliteta: (i) planinski turizam (26,1 %), (ii) sječa starih šuma (19,6 %), (iii) predatori (18,5 %), (iv) šumski radovi tijekom pro ljeća (9,8 %), (v) ispaša stoke u šumama, žičane ograde (6,5 %), (VI i VII) branje šumskih plodova i zaraštanje pašnjaka, (viii) izgradnja šumskih cesta (ix) i ostale infrastrukture. Najznačajniji razlozi promjena i ugrožavanja stani š ta između 1980. i 2000. g. bili su: razvoj planinskog turizma, predatora na staništima, radovi u šumama u proljeće, divlje pašarenje goveda i ovaca u šu-mama, zaraštanje posljednjih pašnjaka u šumskim područjima. Usporedba po većanja postotaka ugroženih lokaliteta od grabežljivaca od 1980 godine pokazala su pozitivne korelacije s povećanjem gustoće populacija glavnih grabežljivaca. Gustoća naseljenosti kuna (Martes spp.) i divlje svinje (Sus scrofa) porasla je za 150 %, dok se gustoća naseljenosti lisice (Vulpes vulpes) povećala od 1990. g. (za 35 %). Naši rezultati potvrđuju ocjenu uzroka nega tivnog utjecaja na pjevališta, a temelje se na opisima i iskustvima promatrača kao prikladan pristup za procjene rizika za staništa tetrijeba. Spoznaje o uzro cima sadašnjeg pada pojavnosti tetrijeba nameću donošenje smjernica koje bi omogućile promjenu načina gospodarenja šumama i divljači u cilju podizanju kvalitete staništa za ovu vrstu

Preservation of forest soil and vegetation in the Capercaillie (Tetrao urogallus L.) habitat within the eastern Karavanke region an the eastern Kamnik-Savinja Alps in Slovenia

In the high-montane zone of the eastern Karavanke range and the eastern Kamnik-Savinja Alps of Slovenia, the soil and vegetation conditions on nine representative plots in the Capercaillie (Tetrao urogallus L.) habitat were studied. The research was carried out on plots in different forest types within the Capercaillie leks, selected with regard to the different bedrock, exposure and level of forest degradation. By contrast to the well preserved beech forest, degradation processes in dystric soil on andesite tuff and gneiss of secondary spruce forest in the abandoned pastures were detected. In the forests on limestone and dolomite, the plant species diversity is much higher than in the forests on non-carbonate bedrock. On carbonate and non-carbonate bedrock, too, the level of preservation of forests (secondary forest in pastures vs. co-natural forests on permanent forest land) is significantly reflected in the floristic composition and vegetation structure