Norway spruce ( Picea abies (L.) Karsten) is one of the most economically important conifer species in Europe. Efficient utilisation and processing of its wood require detailed knowledge of its technical properties, as well as the most common wood defects that substantially affect both properties and utilisation. Given the crucial role of wood defects in the roundwood classification system, the primary objective of this study was to identify defects in Norway spruce and to analyse the influence of forest assortment characteristics (diameter and position along the stem) and tree attributes (diameter at breast height and position within the stand) on the size of wood defects. The research was conducted in Bosnia and Herzegovina, within a forest compartment of an uneven-aged, mixed beech and silver fir stand with spruce. Trees were felled and processed into assortments using a chainsaw, predominantly applying the cut-to-length method. After measuring the assortment dimensions, the occurrence of defects was assessed, and their sizes were determined. The analysis showed that, following knots, the most common wood defect was rot, followed by pith eccentricity, compression wood, scars, mechanical damage, and resin pockets. Statistically significant differences were found in the size of knots, ellipticity, and taper among different diameter classes of assortments (p<0.05), as well as assortment positions along the stem (p=0.0000). Also, a statistically significant difference was observed in the size of the knots and ellipticity in relation to both diameter at the breast height and tree position within the stand (p<0.05). Overall, the findings align with previous studies, confirming the higher quality of the lower stem section, as reflected in smaller defect sizes critical for roundwood quality classification, such as knots, rot, ellipticity, and taper.

The study examined the sources of volume loss in spruce and fir roundwood resulting from the prescribed Huber’s formula, the prescribed method of diameter measurement, the prescribed method of length measurement, and the deduction of double bark thickness. The Riecke’s formula was assumed to provide the most accurate determination of log volume and was therefore used to calculate the gross volume of roundwood, serving as the reference value for quantifying the observed losses. For all analyzed sources of volume loss except when applying Huber’s formula, a dependence on diameter class was observed, with losses decreasing as diameter increased. The highest percentage of volume loss for both spruce and fir logs was found when deducting double bark thickness (ranging from 9.1% to 6.4% for spruce and from 10.7% to 7.7% for fir), followed by the prescribed method of diameter measurement (from 7.3% to 1.7%). Additional losses were associated with the prescribed volume calculation formula (from 5.3% to 1.5% for spruce and from 3.7% to 1.1% for fir) and the prescribed method of length measurement (from 3.1% to 2.1%).

The forestry sector is increasingly dealing with a significant lack of labor and faces the difficult task of securing a professional, stable and sustainable manpower. In this study, different strategic directions for strengthening forestry workforce sustainability are presented and evaluated. The considered strategic directions were developed with respect to forestry employees’ views on necessary measures for making the forestry occupation more appealing. Those measures were observed in three categories: (I) stronger recruiting, (II) stronger retention and (III) higher work commitment. The findings of the survey and other performed analyses resulted in the creation of four different strategic directions: (1) the direct financial strategy, implying increased direct monetary compensation as the main instrument and putting focus on labor productivity; (2) the indirect financial strategy, stressing worker wellbeing through indirect material benefits and aiming at performance quality; (3) the educational strategy, focusing on worker training and education and (4) the technical–technological strategy, aiming at the increased utilization of modern machinery and advanced technologies in forest operations. The results of the study include a comparison of the defined strategies by SWOT analysis and the construction of An analytic Hierarchy Process (AHP) model as the multi-criteria tool for strategy evaluation. Considering the possibility and conditions of its implementation in the national forestry sector, the technical–technological strategy has been evaluated as best option to pursue. The objective of the study is to contribute to enhancing the sustainability of forestry workforce by defining critical issues and pointing to specific cornerstones that can assist in formulating effective future policies and strategies in the forestry sector.

Šumske ceste kao trajni građevinski objekti zahtijevaju ispunjene minimalno propisane kvalitete i standarda tijekom izgradnje. Prema dostupnim podacima prosječni troškovi gradnje šumskih cesta u F BiH za 2019. godinu iznosili su 22.282,19 € po dužnom kilometru (Anon 2019a). Ovako niski troškovi gradnje nameću opravdano pitanje kvalitete novoizgrađenih šumskih cesta i potrebno mu je posvetiti odgovarajuću pozornost. Na području F BiH, zbog niza razloga, sve se više grade prilazne ili tzv. tehnološke šumske ceste, koje se zbog činjenice da se radi o vrsti šumskih cesta bez izvedene kolničke konstrukcije mogu koristiti samo po suhom vremenu te zbog toga ne ulaze u obračun klasične otvorenosti šuma. Osim toga, zbog nedostatka odvodnih jaraka i prevelikog uzdužnog nagiba nivelete na ovim cestama mogu nastati nesagledive ekološke posljedice. S obzirom da postojeća otvorenost šuma u F BiH nije na zadovoljavajućoj razini, cilj svih šumarskih poduzeća je njeno povećanje. Kako se gradnjom šumskih cesta bez izvedene kolničke konstrukcije ne utječe na povećanje otvorenosti, količina cesta koju je potrebno izgraditi za dostizanje ciljane klasične otvorenosti ostaje nepromijenjena. Kao rješenje za riješavanje navedene situacije, u praksi se u posljednje vrijeme sve više grade šumske ceste s elementima koji čine kombinaciju sporednih i prilaznih šumskih cesta. U ovom radu je izvršena analiza tehničkih i konstruktivnih elemenata za novoizgrađenu šumsku cestu „Braćinac - Doljanske stijene“ stacionaže 1,72 km. Na osnovi dobivenih rezultata, došlo se do saznanja o elementima koje na ovoj cesti treba unaprijediti kako bi se ista očuvala, odnosno kako bi se omogućilo njeno dugogodišnje korištenje. S tim u vezi evidentirana su odstupanja uzdužnog nagiba nivelete u odnosu na propisane veličine na 41% od ukupne dužine, na 26% od ukupne dužine nagibi škarpi usjeka nisu prilagođeni kategoriji materijala u kojoj su izgrađene, duž cijele šumske ceste nisu izgrađeni odvodni kanali. Navedena odstupanja daju za rezultat propadanje kolničke konstrukcije, s obzirom da su na 24% evidentirana manja, a na 9% veća oštećenja. Imajući u vidu da su mjerenja na terenu urađena samo godinu dana nakon izgradnje šumske ceste, nameće se zaključak da niska kvaliteta gradnje i nepridržavanje tehničkih propisia rezultira ubrzanim propadanje ceste.

The negative influence of timber harvesting on the forest environment is reflected through damage to the residual trees, regeneration, and forest soil. Considering that skidding, a popular extraction method, can cause substantial and severe damage to the remaining stand, the aim of this research was to determine damage to residual trees during skidding by an LKT 81T cable skidder, including oxen bunching. The research was conducted in eastern Bosnia and Herzegovina, in an uneven-aged mixed fir (Abies alba Mill.) and spruce (Picea abies L.) forest with pine (Pinus sylvestris L.) on limestone soils. Tree felling was conducted using a Husqvarna 372 XP chainsaw. Extraction operations caused damage to 6.31% of the residual trees in the stand. The most damage was “removed bark” (65.34%) and occurred on the lower parts of the tree, the butt end (55.11%) and root collar (32.39%). The average size of the damage was 197.08 cm2. A statistically significant correlation was found between the damage position and the diameter at the breast height (p < 0.05) and the damage position and damage size (p < 0.01) by Spearman correlation analysis. The conducted analysis by the chi-squared test showed that there is a statistically significant difference in the proportion of damage for trees with different distances to the nearest skid road (p = 0.0487), but the share of damaged trees did not decrease by increasing the distance from the skid road.

The paper investigates the phenomenon of soil erosion on skid roads/trails. The aim was to discover how and to what extent different longitudinal slopes can influence the occurrence of erosion processes. For this purpose, a total of nine experimental plots were set up at three different sites. The length of the plots was 110 m, and at all localities, the research was carried out on different longitudinal slopes (up to 10%, 10 - 20% and over 20%) over the observed period of approximately two and a half years. The research focused on determining the volume of material removed and the dynamics of the development of erosion processes observed in phases (shifts) between recordings. Forests are the most effective natural factor in protecting land from erosion, and if they are managed on the principles of sustainable management, the so-called "normal" erosion usually occurs. However, as it is necessary to build a relatively dense network of skid roads/trails for different phases of management, it makes them susceptible to more intensive erosion processes. If we take into account that they were built with very low criteria (technical elements) and without the existence of facilities that would ensure the drainage of surface and rainwater, and can be built with a large longitudinal slope, it creates optimal preconditions for the development of intensive erosion process. The conducted research has obtained results that clearly show that erosion processes occur frequently, of varying intensity depending on the factors that prevail for a given locality. The value of the volume of the removed material ranges from 1.278 m3, ie 0.0116 m3/m to 5.313 m3, or 0.0483 m3/m. The obtained minimum value of the volume of the removed material can be related to the strong water permeability of the parent substrate (limestone), which affects the reduction of surface runoff, as well as shallow soils that are formed on it. When it comes to the maximum value of the volume of removed material, which is 5.333 m3 or 0.0483 m3/m, it can be related to the continuous occurrence of surface runoff that causes surface sapping and removal of material from the skid roads/trails. The performed statistical analyzes (through a linear model) indicate different correlations of investigated influencing factors (volume of transported material and length of skid roads/trails on different longitudinal slopes). The obtained correlation values range from r = 0,29 (weak correlation) to r = 0,79 (very strong correlation).

UDK: 630*232:582.475(497.6) It is well known that mechanical damage to trees, caused by felling and removal of timber from the forest, has multiple negative effects on the quality of the stock and the health of the forests as well as the volume increment. In Bosnia and Herzegovina there were no significant analises of volume increment loss due to bark damage of the trees. In this paper, a direct relationship between the significant damage to the bark of the stem and the size of the volume increment of individual trees was determined. Original data recorded during the Second National Forest Inventory in Bosnia and Herzegovina (2006-2009), within the accesible high economical forests was used. These forests cover a total area of 1.329.500 ha. Data on measured trees was taken from every fourth sample plot (one from cluster). 18.546 trees were selected, on which the 10-year increment of brest diameter (DBH) was measured and significant mechanical damage was recorded (LOJO et al., 2008). Of the total number of selected trees, 2.635 or 14.21% were mechanically damaged. The results of the study showed that the volume increment of trees, with significant bark damage of all tree species and thickness, was lower from 4,9% to 19,4% in average, compared to undamaged trees. Based on registered damage the bark of the stem, during second NFI BiH and determined the average losses increment on individual trees, it was estimated how much these losses are on an annual basis in, productive high forests in Bosnia and Herzegovina. The volume increment of mechanically damaged trees is statistically significantly lower compare to the increment of undamaged trees, resulting in a total loss of about 200.000 m3 / year / 1.329.500 ha.

U radu su prikazani rezultati istraživanja učinkovitosti skidera Ecotrac 55V. Istraživanje je provedeno u šumskom odjelu 89, gospodarska jedinica »Igman«, uz primjenu studija rada i vremena. Trajanje radnoga vremena ustanovljeno je »povratnom« metodom snimanja. Ovisnost vremena trajanja radnih operacija o utjecajnim čimbenicima utvrđena je uz primjenu višestruke regresijske analize. Primijenjena je sortimentna metoda izrade drva. Snimljeni su ovi utjecajni čimbenici: stanje traktorskoga puta (podloge), udaljenost privlačenja drva skiderom, udaljenost privitlavanja drva, broj komada u tovaru, obujam tovara i uzdužni nagib traktorskoga puta. Udio operativnoga vremena u ukupnom radnom vremenu iznosi 38,75 %, a udio vremena prekida rada 37,56 %. Norme vremena i učinka izražene su u ovisnosti o udaljenosti privlačenja, dok su za ostale utjecajne čimbenike korištene prosječne vrijednosti. Utvrđena je norma vremena u iznosu od 8,34 min/m3 za udaljenost privlačenja od 100 m, odnosno 17,65 min/m3 za 900 m. Učinak se traktora kreće u intervalu od 57,58 m3/radnom danu za udaljenost privlačenja od 100 m do 27,20 m3/radnom danu za 900 m. Analiza je pokazala da postoji mogućnost povećanja učinkovitosti primjenom bolje organizacije rada i smanjenjem udjela prekida rada u ukupnom radnom vremenu, osobito prekida iz organizacijskih i osobnih razloga (prekida zbog jela i prekida zbog odmora i osobnih potreba radnika).

Current tables of wood assortments for the most important tree species in B&H were made almost 50 years ago. There is an indication that real forest wood assortments are different than the one derived from assortment tables in-use, both in terms of quality and dimensions. In the meantime, from the creation of the existing tables until today, the standards of production of forest wood assortments have changed, so that the fact of inaccuracy of the existing assortment tables is unquestionable. This continually creates a variety of problems in the ongoing operations of forestry companies. The main aim of this paper is to create wood assortment tables whose assortment of wood products will correlate with the current market conditions. The research was conducted in the area of the Canton 10 in FB&H.  A sample of 393 spruce trees was used as a database to produce this paper. The bucking of the sample trees was carried out in accordance with the valid norms and customer requirements with regards to the dimensions of forest wood products. Data processing was performed using methods of simple and multiple regressions, variance analysis as well as their combinations by the Generalized Linear Models method. Independent factors were breast diameter (DBH), technical quality class and the height of the trees. The share of wood assortments was determined through 10 different mathematical models, and it was found that all independent variables had a statistically significant influence on the dependent variables- volume of particular assortments or group of assortments. The share of logs is growing rapidly with the increase of tree diameter and decreases with decreasing of their technical quality. The influence of tree height primarily correlated with tree volume increase. Trees having better assortment quality, have tree heights higher than average for the same diameter class. The results of the research are presented in the form of tables as percentage share of wood assortment classes.  The obtained results can be used as wood assortment tables in the research area.