111. Bukovina - povezave med kakovostjo dreves, hlodovine in žaganega lesaJurij Marenče, Dominika Gornik Bučar, Bogdan Šega, 2016, izvirni znanstveni članek Povzetek: V raziskavi smo preučevali količinsko-kakovostni izkoristek bukovine od stoječega drevesa do žaganega lesa. Zanimala nas je ocena kakovosti posameznih dreves in njen vpliv na kakovostne razrede proizvodov iz tega lesa. Pri razvrščanju stoječih dreves smo upoštevali aktualno 5-stopenjsko lestvico ocenjevanja kakovosti Zavoda za gozdove Slovenije (ZGS). Pri ocenjevanju gozdnih sortimentov smo uporabljali standard SIST EN 1316-1:2013, pri ocenjevanju žaganega lesa pa pravila Evropskega združenja žagarske industrije (EOS). Na vzorcu ocenjenih in nato posekanih dreves smo ugotavljali povezave med kakovostjo dreves, iz njih izdelanih sortimentov okroglega lesa in kakovostjo končnih žagarskih izdelkov. V vzorec so bila enakovredno zajeta drevesa vseh petih kakovostnih stopenj. Pri izdelavi gozdnih sortimentov smo dobili največ hlodov B-kakovosti (51 %) in največ žaganega lesa EOS-C-kakovosti (52 %). Iz bukovih dreves odlične kakovosti smo dobili 35 % najkakovostnejših sortimentov in iz teh sortimentov 8 % najkakovostnejšega žaganega lesa. Odločilni kriterij razvrščanja po kakovosti so pri sortimentih okroglega lesa slepice in pri žaganem lesu mrtve in trhle grče.
Ključne besede: listavci, bukev, kakovost, napake lesa, žagan les
Objavljeno v DiRROS: 12.07.2017; Ogledov: 5154; Prenosov: 2662
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112. Presoja varovalnega učinka gozda pred snežnimi plazovi : primer ruske ceste pod VršičemAndrej Rozman, Jurij Diaci, 2016, izvirni znanstveni članek Povzetek: Cesto na Vršič ogrožajo snežni plazovi, gozdovi nad njo pa opravljajo zaščitno in varovalno funkcijo pred njimi. Analizirali smo potencialno ogroženost dela ceste in gozda nad njo, opravili presojo zaščitne funkcije gozda pred snežnimi plazovi ter določili smernice in ukrepe za nadaljnji razvoj gozda in krepitev njegovega varovalnega učinka. Na objekt raziskave smo postavili mrežo 21 raziskovalnih ploskev. Po modificirani metodi NaiS (Frehner in sod., 2005) smo izločili in opisali sestoje ter primerjali njihovo dejansko stanje s ciljnim, ki zagotavlja zaščito pred snežnimi plazovi. Glede na naklon in pokritost z gozdom smo naredili karto, ki kaže najbolj ogrožena območja pred snežnimi plazovi. Ugotovili smo, da noben sestoj ne zagotavlja popolne in trajne zaščitne funkcije. Največji problem sta pomlajevanje in zagotavljanje raznomerne strukture sestojev. Najpomembnejše smernice za nadaljnji razvoj gozda so pospeševanje raznomerne in raznodobne strukture, zagotavljanje pomladka, vzgoja čim večjega števila nosilcev stabilnosti ter zagotavljanje dobre vitalnosti in zadostne gostote dreves.
Ključne besede: varovalni gozdovi, varovalna funkcija gozdov, zaščitna funkcija gozdov, snežni plazovi, upravljanje varovalnih gozdov, smernice za upravljanje z gozdovi, gojenje varovalnih gozdov
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4813; Prenosov: 2266
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113. Sobivanje jelke in bukve v Dinaridih : usmeritve za ohranitveno gospodarjenje z jelkoJurij Diaci, Dušan Roženbergar, Thomas Andrew Nagel, 2010, pregledni znanstveni članek Povzetek: Drevesna sestava jelovo-bukovih gozdov se v prostoru in času spreminja. Nanjo vplivajo številni naravni in antropogeni dejavniki, ki delujejo neposredno ali posredno. Oblikovanje usmeritev za gojenje gozdov zato zahteva dobro poznavanje delovanja lokalnih ekoloških, zgodovinskih, gospodarskih in splošnih okoljskih dejavnikov. V prispevku prikazujemo sintezo štirih skupin raziskav, ki smo jih izpeljali v dinarskih jelovo-bukovih gozdovih v zadnjem desetletju in obravnavajo: 1) ekologijo pomlajevanja v manjših in srednjih vrzelih, 2) odziv sestojev v pragozdu Perućica na motnje srednjih jakosti (vetrolomi), 3) dolgoročne spremembe v vrstni sestavi pragozdov v jugovzhodni Evropi, in 4) odvisnost pomlajevanja v gospodarskih gozdovih od gozdnogojitvenega sistema. Namen prispevka je prikazati vlogo jelke v razvoju jelovo-bukovega gozda ter poudariti procese, ki vodijo v njeno sobivanje ali izločanje. Raziskave ekologije pomlajevanja nakazujejo, da je jelka uspešnejša na posebnih mikrorastiščih (hladnejše in vlažnejše razmere, odmrla drevesa, večja skalovitost, nižji pH tal, skromne svetlobe razmere). Na vetrolomnih površinah srednjih jakosti prevlada bukev, jelka pa se nasemeni kasneje v strnjena bukova mladovja. Naše raziskave niso potrdile hipoteze o lažjem uveljavljanju jelke v večjih sestojnih vrzelih gospodarskih gozdov. Spremembe vrstne sestave pragozdov v Sloveniji in jugovzhodni Evropi nakazujejo nazadovanje jelke v zadnjih petdesetih letih, kar je posledica več skupin vzrokov, še posebej zračnega onesnaženja in objedanja po divjadi. V Sloveniji je zmanjševanje deleža jelke v Dinaridih izrazito hitro. Primerjave z jugovzhodno Evropo kažejo, da so sicer raznovrstne strategije uveljavljanja jelke v Sloveniji neuspešne zaradi visokih gostot velikih rastlinojedih parkljarjev.
Ključne besede: jelka, Abies alba, bukev, Fagus sylvatica L., sobivanje, medsebojno nadomeščanje, objedanje mladja, propadanje gozdov, gojenje gozdov, Dinaridi, Dinarsko gorstvo
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4634; Prenosov: 2002
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114. Bucking of conifers using the woody H60 processor on the Syncrofalke 3 T cable yarder in Alpine foothillsJurij Marenče, Jernej Vadnjal, Boštjan Košir, 2009, izvirni znanstveni članek Povzetek: The paper investigates mechanized bucking of conifers with a processor mounted on a cable crane system in the mountain conditions of the Alpine foothills. It analyses the measurement accuracy of various log types and explains its effect on the market price of these products. In the studied area, trees were felled by chain saw and the full-tree method was used to skid the felled trees to the cable yarder site using the Syncrofalke cable crane with a mounted Woody H 60 processor head. Further wood processing operations were carried out at the yarder site. Length measurement accuracy was illustrated through the frequency distribution and the modus of various lengths. The share of logs within a 5 cm interval - modus - (the best five) was 54.3%. The difference between the nominal log length and the minimum required length resulted in a loss of 4.38% of the total log value. Further more, it was established that the first quarter of the stem actually contained 64% of the total stem value. This means that the first cross-cut was responsible for nearly 50% of the total loss and the second crosscut pushed the figure to 80%. The present research only considered the losses incurred either by positive or negative cross-cut allowance or by insufficiently accurate length measurement of a certain log type.
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4172; Prenosov: 1860
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115. Zgradba in razvoj pragozdov in ohranjenih bukovih gozdov v EvropiTihomir Rugani, Thomas Andrew Nagel, Dušan Roženbergar, Dejan Firm, Jurij Diaci, 2008, pregledni znanstveni članek Ključne besede: bukev, Fagus sylvatica L., pragozdovi, gozdni rezervati, struktura gozdov, dinamika gozdov, režimi motenj, gojenje gozdov
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4717; Prenosov: 1931
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116. Assessing maximum loads when skidding wood uphill with tractorsBoštjan Košir, Jurij Marenče, 2008, izvirni znanstveni članek Povzetek: 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.
Ključne besede: tractor, skidding wood, maximum slope, maximum load
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4380; Prenosov: 1823
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117. Technical parameters dynamics of WOODY 110 cable skidder within the range of stopping due to overload in uphill wood skiddingJurij Marenče, Boštjan Košir, 2008, izvirni znanstveni članek Povzetek: The article deals with uphill wood skidding with WOODY 110 skidder and the changes taking place in technical parameters: slip, torque, tractive forces, and weight distribution of a loaded tractor in the last three meters of skidding, which is defined as a range of stopping due to overload. The test was performed on a concave skid trail, where tractor loaded with 8 meter long fir logs stopped at the 32% incline. It stopped somewhat later when skidding with butt-end forward in comparison to skidding with top-end forward. The loadweight with butt-end forward was 31.69 kN, whereas with top-end forward itweighed 33.53 kN. The measured speeds showed minute changes until the last meter, but decreased swiftly after stopping. Regarding some technical parameters, there were almost no changes at the end of stopping, two exceptions being the slip, which increased in the range of stopping, and the forward torque, which decreased in this range. The results showed that the hydrostatic transmission was efficient, considering that in a relatively well-controlled slip (the slip values increase only in the last three meters, which approximately equals the half of tractor's length) there was less grounddamage.
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4242; Prenosov: 1835
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118. Pomladitvena ekologija drugotnih visokogorskih smrekovih gozdov v JelendoluElizabeta Rozman, Jurij Diaci, 2008, izvirni znanstveni članek Povzetek: Pomlajevanje visokogorskih smrekovih gozdov v Jelendolu je oteženo zaradi spleta dejavnikov. Jeseni leta 2003 smo v veliki vrzeli, malih vrzelih in pod sklenjenim sestojem na mreži 5 x 5 m postavili skupaj 227 ploskvic velikosti 1,5 x 1,5 m z namenom ugotoviti splošne pomladitvene razmere in glavne zaviralne dejavnike pomlajevanja. Na ploskvicah smo zbrali podatke o ekološkihrazmerah (relief, lega, nagib, globina tal, sestava površja, direktnoin difuzno sončno sevanje), vrsti in pokrovnosti pritalne vegetacije ter vrstah, gostoti, višinah in priraščanju mladja. Asimetrija v osvetljenostije vidna tako v smeri N-S kot E-W. Glede na porazdelitev direktnein difuzne svetlobe smo ploskvice razdelili na štiri skupine. Smreka je dobro pomlajena (28.605 na ha), zlasti izrazit je rob velike vrzeli, vendargostota mladja ni značilno odvisna od svetlobe. Nasprotno pa pomanjkanjesvetlobe onemogoča nadaljnji razvoj v sestoju in v malih vrzelih. Rezultati so pokazali, da svetlobne razmere na 1.500 m n.v. niso edini dejavnik, ki vpliva na uspešnost pomlajevanja. Velik pomen imajo še zlasti lesni ostanki, medtem ko je vpliv zeliščne plasti (prevladujeta Festuca altissima All. in Calamagrostis arundinacea (L.) Roth.) in globine tal negativen. Največji problem je še vedno objedanje.
Ključne besede: visokogorski gozdovi, smrekovi gozdovi, pomlajevanje, ekološki dejavniki, sončno sevanje, vrzeli, Jeledol
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4678; Prenosov: 1986
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119. Measuring the limits of uphill timber skidding with a WOODY 110 forestry tractorBoštjan Košir, Jurij Marenče, 2007, drugi znanstveni članki Povzetek: The paper deals with the test results of uphill skidding of wood with a WOODY 110 cable skidder. The aim of the study was to find the limits of uphill skidding in relation to load size, log orientation and the slope. The trial was prepared on a test track of concave shape in the forest and with pre-designed loads of different sizes. The loads were skidded uphill once withbutt-end and then with top-end forward, until the tractor stopped because of the slope. The results show that butt-end forward skidding is more efficient. The difference between maximum loads at specific maximum slopes is almost constant (0.53 t). Proper load formation (butt-end forward if possible)is more important when skidding on steeper slopes.
Ključne besede: forestry, tractor, skiiding, maximum slope, maximum load
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4324; Prenosov: 1945
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120. Wheelslip in skidding with the AGT 835 T adapted farm tractorJurij Marenče, Boštjan Košir, 2007, izvirni znanstveni članek Povzetek: The paper presents a wheelslip measurement method for small farm tractors (AGT835 T) adapted for skidding, with mechanical and hydrostatic mechanical transmissions. The research focused on uphill skidding, as slip values measured in uphill skidding are higher than in downhill skidding. A comparisonwas made of the performance of tractors carrying equal load but equipped with mechanical and hydrostatic transmission systems. The hydrostaticdrive causes higher negative load values in downhill skidding, and slightly higher slippage. As for hydrostatic tractors, wheelslip is higher in uphill skidding than in downhill skidding. The increase in the sloping of the terrain causes wheelslip to rise progressively. When a tractor travels uphill,slip is linked to a loss of energy. Wheelslip measurements are therefore important for determining the optimum conditions for individual tractor types.
Ključne besede: skidding, farm tractor, wheelslip, measurement
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4439; Prenosov: 1936
Celotno besedilo (722,66 KB) |
