Primerjava različnih regresijskih modelov za napovedovanje debelinskega priraščanja jelke

We present seven alternative statistical models for modelling tree diameter increment with data from permanent sampling plots. In addition to the polynomial regression model, we present a regression model with added random noise, a mixed linear model, regression with natural splines, and three models with limited dependent variables: truncated regression, tobit regression and grouped data regression. The models may be used when dealing with truncated or censored variables, biased estimation of the increment due to censoring and rounding down, or when having multilevel data. The parametrization of the models was done using 21,013 fir trees on 4,405 plots in the period 1990–2014 in uneven-aged Dinaric fir-beech forests. All models showed a similar effect of tree diameter, stand basal area, basal area of larger trees, diameter structure diversity, altitude and slope. There were only minor differences in the regression coefficients and fit measures. The highest increment predictions were given by the tobit model. The mixed model fit the data best and, compared to the other models, predicted a slower decrease in the growth of large-diameter trees after growth culmination.

Phenological variability and resistance to late spring frost of common beech in the international provenance test in Bosnia and Herzegovina

The research aimed to determine the start, end and duration of leafing phases, the degree of plant damage caused by late spring frost, and the retention of leaves in autumn. The research was conducted in the international common beech provenance test in Bosnia and Herzegovina. The test contains eight provenances from Bosnia and Herzegovina, four from Germany, three from Serbia, two each from Croatia, Romania and Switzerland, and one from Hungary. Leafing phenology, canopy damage caused by late spring frost, and leaf retention were assessed in 2019. Most provenances started opening buds on 17 April 2019. Complete canopy damage affected the highest percentage of plants in provenance BW Bad Wildbad, Germany (68 %), and the lowest in provenance Konjuh Kladanj, Bosnia and Herzegovina (3.2 %). Provenance Herzogenbuchsee from Switzerland had the highest percentage of winter leaf retention (37.5 % of plants). The results can be used in choosing provenances that are resistant to low temperatures in zones of late spring and early autumn frost.

Assessment of the condition of Balsam poplar trees (Populus balsamifera L.) in a residental area of Bratsk

In this study, we investigated the health status of balsam poplar (Populus balsamifera L.) trees in a residential area of the city of Bratsk (Irkutsk Oblast, Russia). Visual and instrumental assessment of the health status of pruned and unpruned trees was performed. The identified internal defects in the tree were analyzed with a Resistograph device, which enabled the extent of decayed wood to be determined. Visual analysis revealed various types of damage: dried branches, brittle crowns, frost cracks, mechanical damage, curvature of trunks, decay and inclusions of foreign bodies. We compared trees with and without canopy pruning. We found that pruned trees were significantly more damaged than non-pruned trees. Decomposing wood at different stages of development was found in all the trees studied. A tree passport combining the visual and instrumental assessment data was compiled for each tree. The results of the research were used to formulate conclusions and recommendations for improving the management of urban trees in order to restore their ecological and aesthetic functions.

Vplivi na obisk gozda v splošnih in gozdnih vrtcih

Preschool children spend a large part of their everyday life in kindergartens, so it is necessary to include visits to the forest, which is the most extensive natural environment in Slovenia, in preschool childcare programs. Based on surveys with preschool teachers of public kindergartens in Slovenia (N = 133), we analysed the habits, purposes, barriers and concerns associated with visiting the forest. The frequency and duration of forest visits largely depend on the distance of the forest from the kindergarten. The habits of forest visits among forest kindergartens which are included in the Network of Forest Kindergartens organized by the Institute of Forest Pedagogy do not differ significantly from that of general public kindergartens. They differ mainly with respect to the frequency of visitation in bad weather and the purpose of visitation. The main concerns when visiting the forest are ticks, fear of injury, and the children having inappropriate equipment. The reasons for less frequent forest visitation include different pedagogical priorities of the kindergartens and lack of support from the management and parents, which highlight the need for the strategic promotion and implementation of forest visitation in preschool education.

Participativni pristop pri pripravi upravljavskih načrtov na primeru izbranih gozdnih habitatnih tipov in živalskih vrst ob Muri

For Natura 2000 areas, the European Commission proposes the drafting of management plans that include site-specific objectives and conservation measures based thereon. In order to avoid potential subsequent conflicts, the process needs to involve all stakeholders early on and in a sensible manner. In the framework of the project GoForMura, management plans for the Natura 2000 forest sites in the study areas of Gornja Bistrica and Murska Šuma in the Prekmurje region were drafted as model plans. The participation of stakeholders, in particular forest owners and managers, was given special attention in the drafting of what were the first such documents.

Priraščanje navadne smreke (Picea abies (L.) Karst.) in evropskega macesna (Larix decidua Mill.) na nekdanjih novinah v koprivni v Karavankah

Based on previous measurements from 1962 to 2017 on forest research plots located on former slash-and-burn farming areas in the cadastral municipality of Koprivna, the diameter and height increment as well as volume increments of the two main tree species - spruce and larch - were calculated. These set-aside natural research plots have a smaller mean basal area diameter, but the number of trees is higher than in comparable managed forests. Due to the high-density of tree stands over the past thirty years, radial increment of spruce and larch has declined. To determine the influence of environmental factors on radial growth of spruce and larch, a dendrochronological analysis was conducted. According to the dendrochronological analysis of radial increment of trees, the number of years with a negative response has been higher since 1984.

Modeliranje višinske in debelinske rasti dominantnih dreves ter ocenjevanje indeksov produkcijske sposobnosti gozdnih rastišč

Modeling the height and diameter growth of trees is an important part of forest management. Growth models provide the basis for determining the thinning regime, target tree dimensions and optimal proportions of developmental phases of forest stands. We developed individual height growth models for dominant Norway spruce (Picea abies (L.) Karst) and European beech (Fagus sylvatica L.) in two forest types (sessile oak-European beech forests and pre-Alpine silver fir-European beech forests). Based on the models, the site productivity index (SPI), defined as the dominant tree height at a diameter of 45 cm, was determined for spruce and beech in both forest types. Based on the diameter increment of the dominant trees, the age of trees in regard to their diameter was calculated, which was the basis for Height-Age modeling. The site productivity index (SPI) of spruce in sessile oak-beech forests and pre-Alpine silver fir-European beech forests is higher than that of beech: 31.3 and 29.7 vs 28.7 and 27.9, respectively. Estimated site indices (SI; dominant tree height at the age of 100 years) in sessile oak- European beech forests and pre-Alpine silver fir-European beech forests were 33.4 and 32.0 for spruce, and 29.0 and 27.0 for beech, respectively. Using the described procedure, it is possible to determine indices of site productivity of spruce and beech (SI and SPI) in the selected forest habitat types. Testing the procedure in other forest types and for other tree species is suggested.

Vpliv podnebnih sprememb na dinamiko glivnega razkroja lesa v Sloveniji

The intensity of fungal decay depends mainly on wood species, temperature and precipitation events. To estimate the planned service life of wood and to determine the maintenance intervals of wooden buildings, it is necessary to assess how wood behaves in a given environment. There are a variety of models that have been developed to assess the loading of wood. The approach most commonly used in practice is that developed by Theodore Scheffer. Scheffer proposed a climate index (Scheffer climate index) based on the number of rainy days and monthly average temperatures. Based on these data, Scheffer climate index for chosen locations in Slovenia was calculated. The results of the analysis of climatic conditions show that the Schef%fer climate index is higher than it was decades ago at most of the analysed sites in Slovenia. The intensity of decomposition increased at all analysed locations, with the exception of Portorož. The largest increase in the Scheffer climate index was ob%served in Rateče.

Aktiviranje gospodarjenja v zasebnih gozdovih s poslovnim sodelovanjem med zasebnimi lastniki gozdov in ponudniki gozdarskih storitev: študij primera revir Vodice

We investigated the possibility of activating private forest management through business cooperation within 'forest lease' and 'forest management' business models between private forest owners (PFOs) and forest service providers. By surveying PFOs (n = 205) and forest service providers (n = 14), we found that the willingness to engage in business cooperation in both proposed business models is higher among forest service providers than PFOs. In addition, we found that business cooperation within the proposed business models is feasible because the level of cooperation of PFOs with forest service providers over a 10-year period is satisfactory, and the proposed terms and conditions governing the business relationship and basic contract obligations of the contracting parties have proven to be appropriate for both business partners. In order to establish business cooperation, it is first necessary to promote business cooperation at the local level and to establish business relations between potential partners.

Značilnosti opravljanja sečnje in spravila v zasebnih gozdovih v Sloveniji

A survey conducted in 2019 covered 544 randomly selected forest owners. More than half of the forest owners own a forest estate ranging from 1 to 4.99 ha. For 62 % of respondents, the primary purpose of forest management is to harvest wood for their own needs. In 2015%2019, 71 % of respondents carried out felling and skidding in their forests. In total, approximately 50,000 m3 of wood was felled (24 m3 /ha or 141 m3 per holding). The largest volumes were felled by private owners with small forest holdings (up to 0.99 ha), on average 41.4 m3 /ha. There were statistically significant differences between the size of the forest holding and the average volume of annual felling. Furthermore, there were no statistically significant differences in felling intensity between male and female forest owners. The survey found that professional contractors carried out 41 % of felling and harvesting. Furthermore, there were significant differences between the size of the private forest estate and the method of performing forest operations. The results showed that the largest share of private owners who carry out all felling and skidding with the help of hired contractors is in the size class of forest holdings from 5 to 9.99 ha. The study did not confirm statistically significant differences in the intensity of felling between male and female private forest owners.