Poštovane čitateljice i čitatelji!

Od najvažnijih događanja u šumarskom inženjerstvu na međunarodnom će se planu u 2008. godini održati dva savjetovanja u Europi, u Pragu (Republika Češka) i u Schmallenbergu (Njemačka). U Pragu se od 26. do 30. svibnja 2008. godine, u organizaciji Fakulteta šumarstva i drvne tehnologije iz Brna i Ministarstva poljoprivrede Republike Češke, održava međunarodni simpozij FORTECHENVI 2008. Pokrovitelji su toga simpozija IUFRO grupa 3, sekcija 3.05.00. Ekološka sastavnica šumskih radova (Forest Operations Ecology), i Europsko društvo inženjeraa gronomije (European Society of Agriculture Engineers). Cilj je savjetovanja predstavljanje najnovijih znanstvenih dostignuća i rezultata…

Due to complexity of the current business environment and imperative of ecological acceptability and business success, the management of forestry organisational units must perform continuous analyses of all relevant indicators of business efficiency. Under such circumstances, it is difficult to evaluate business success by traditional approaches. This paper considers additional efficiency evaluation techniques applicable in benchmarking of organisations dealing with environmental management, whose success is determined not only by financial profit but also by assessment of their ecological dimension. Using Data Envelopment Analysis (DEA), the efficiency of the Croatian forestry operating units was evaluated taking into consideration their business result, as well as quantities of hazardous waste produced. By the basic DEA models, the efficiency level of mechanisation in 13 operating units within the company Hrvatske šume d.o.o. Zagreb was determined, and the projection of inefficient units on efficiency frontier was established, as well as sources and rates of inefficiency. The results show that the Data Envelopment Analysis may be a very useful tool at a strategic and operational level of decision making in forestry. This paper also shows the advantages and possibilities of applying the DEA method, as well as restrictions of this model.

Keywords: Data Envelopment Analysis (DEA), efficiency, forestry, operating units, environment, hazardous waste

This paper presents a morphological analysis of different types of hydraulic cranes installed on forest vehicles with the aim of determining their technical characteristics as well as possibilities of their use. A database of technical characteristics of 231 types of hydraulic cranes was compiled for the morphological analysis. Hydraulic cranes were divided into four groups according to the vehicle on which they were to be installed (tractor, forwarder, harvester and truck). Six basic technical characteristics were chosen: gross lifting capacity, slewing torque, mass, outreach, working pressure and oil flow. On the basis of the investigated technical characteristics it may be concluded that hydraulic cranes for trucks have the highest values of lifting capacity, mass and working pressure. Wide ranges of technical characteristics of hydraulic cranes for trucks and tractors indicate the possibility of their wide application for different working demands. Hydraulic cranes for harvesters show the highest values of outreach and oil flow which may result in reduced vehicle movement along the forest site and increased work efficiency.

Keywords: hydraulic crane, technical characteristics, forest vehicles, morphological analysis

Research of wheel load distribution of skidders in timber extraction was carried out on a skid road where longitudinal slopes were determined by levelling method as well as distances on a skid road with the same slope. A skidder was used for timber extraction of 9 different loads in two directions – uphill and downhill. Values of vertical and horizontal component of rope force and wheel loads were measured by tensiometric method in each skidding test.

Wheel loads on the rear axle increase with increase of load weight and slope during uphill skidding. Vertical component of rope force always has higher values than horizontal component during downhill skidding while horizontal component of skidder weight (G sin α) transfers the weight from rear axle to front axle.

According to the results, vertical component of winch rope force seriously affects wheel load, because this force burdens the skidder in full amount. It could be concluded that the correct way of timber skidding is to lift off the heavier end of load in the aim to increase adhesive weight of the skidder and to decrease skidding resistances.

Keywords: skidder, wheel load, adhesive weight, timber extraction, longitudinal slope

By research of volume losses of processed spruce roundwood, with respect to the prescribed method of scaling roundwood and volume calculation in the Croatian forestry, the following sources of loss have been determined: prescribed expression for the calculation of volume (Huber’s formula), prescribed method of diameter measurement, deduction of the double bark thickness, prescribed method of length measurement.

Riecke’s formula was assumed to be the most accurate formula for the assessment of roundwood volume. Based on this formula, the gross roundwood volume was calculated and it represented the reference value for expressing volume losses caused due to the prescribed method of scaling.

The dependence of the values of volume losses on thickness class of processed roundwood was recorded with the following sources of loss: prescribed formula for the calculation of volume (Huber’s formula), prescribed method of diameter measurement, and deduction of the double bark thickness. For all the above said sources of loss, the decrease of values of volume loss was recorded with the increase of roundwood mid-length diameter class. Deduction of the double bark thickness was determined as the biggest source of volume loss of roundwood (from 16.9 vol. % to 5.8 vol. %), and it was followed by: prescribed method of diameter measurement (from 10.1 vol. % to 1.8 vol. %), prescribed formula for the calculation of volume (from 3.9 vol. % to 0.3 vol. %), and prescribed method of length measurement (from 0.7 vol. % to 0.4 vol. %).

Total volume loss due to the prescribed method of scaling spruce roundwood shows a tendency to decrease exponentially with the increase of roundwood mid-length diameter class, from 28.1 vol. % (class of 12.5 cm) to 8.8 vol. % (class of 67.5 cm). The artificial increase of the values of volume loss in the mid-length diameter class of 22.5 cm (23.8 vol. %) is the consequence of »tooth« effect in the tables of bark deduction.

Keywords: volume loss, roundwood scaling, spruce roundwood

Ususretnost jezikoslovlja i šumodjelskoga nazivoslovlja – proslov i dobrodošlica Pregrštu jezičnih zrnaca

Kada je šumarstvo koračalo već stoljetnom stazom skrbi za šumu, njezinu obnovu i korištenje, kasnih se šezdesetih godina posljednjega stoljeća prošloga tisućljeća počela u njezin život uvlačiti novost zvana mehanizacija. Kao svaka novost, i njoj su se jedni divili, drugi ju prezirali, treći vjerovali u nju i bez divljenja i omalovažavanja shvaćali da ju treba prihvatiti kao svoju–mehanizaciju šumarstva…

Tijekom prosinca 2007. godine iz tiska je izišao sveučilišni udžbenik doc. dr. sc. Dragutina Pičmana pod naslovom »Šumske prometnice«. Riječ je o prvom sveučilišnom udžbeniku koji se bavi problematikom šumskih prometnica i koji je objavljen na Šumarskom fakultetu Sveučilišta u Zagrebu (u Zavodu za šumarske tehnike i tehnologije) nakon 1955. godine, kada je svjetlo dana ugledalo vrijedno i kapitalno djelo prof. dr. sc. Stanka Flögla »Gradnja šumskih putova i pruga«. Budući da je udžbenik sveučilišni, primarna mu je zadaća pomoć studentima…

Od 8. do 11. listopada 2007. u Beču je održano združeno savjetovanje Austro 2007 – FORMEC ’07 (40. međunarodni simpozij »Mehanizacija šumskoga rada«) pod naslovom »Ususret potrebama sutrašnjih šuma: Nova kretanja u šumskom inženjerstvu« (Meeting the Needs of Tomorrows’ Forests: New Developments in Forest Engineering) u suorganizaciji Zavoda za šumarsko inženjerstvo Odjela za šume i tloznanstvo Sveučilišta u Beču (BOKU), Odjela za šumarstvo Tehničkoga sveučilišta Virdžinija (USA), Austrijskih saveznih šuma, Ministarstva poljoprivrede, šumarstva, okoliša i vodnoga gospodarstva Republike Austrije te Ureda za šumarsvo i poljoprivredu grada Beča…