Martin Bobinac

Absence of geographical structure of morphological variation in Juniperus oxycedrus L. subsp. oxycedrus in the Balkan Peninsula

We examined leaf and mature seed cone variation of Juniperus oxycedrus L. subsp. oxycedrus in 12 natural populations across the species range in the Balkan Peninsula. We measured 10 morphological traits from a minimum of 100 leaves in each of 190 individuals, and two morphological traits from 30–50 seed cones in each of 94 females. High phenotypic variation was found, but no geographical structure or cline across populations was detected for any of the studied traits. Mean values of comparable leaf and cone morphological traits did not differ considerably from values reported elsewhere. Gender dimorphism in leaf morphology was detected, but it was not distributed uniformly throughout the studied area. An ANOVA model with both nested and crossed effects revealed that the largest proportion of the total variation was, as expected, contained within populations, partly as among-tree variation (18–47%, depending on the trait) and partly as within-tree variation (33–77%), which was remarkably high. Gender dimorphism explained only 0–3% of the total variation. Differences among populations (2–23%) were significant for all studied traits except one; however, PCA showed no clear geographical differentiation of the studied populations. This lack of phylogeographical structure may be the consequence of repeatedly occurring colonisation-retreat scenarios and suggests the existence of several small refugial populations scattered over a large part of the Balkan Peninsula in the Pleistocene. Further research including palaeobotanical and molecular genetic studies will be needed to better understand the forces that shaped current variation patterns of J. oxycedrus L. subsp. oxycedrus in the Balkan Peninsula.

Leaflet morphometric variation of service tree (Sorbus domestica L.) in the Balkan Peninsula

Abstract In most European countries, the service tree (Sorbus domestica L.) is a rare and threatened species and its conservation has been recognised as a priority. The aim of this study was to asses its morphologic variation in the western and central part of the Balkan Peninsula and in southern Central Europe. Three populations were analysed: one in Serbia, one in Bosnia and Herzegovina and one in Slovenia. In each population 30 trees were selected, and from each tree 30 leaves were collected for morphometric analysis based on nine leaflet morphological traits. Univariate (ANOVA) and multivariate (MANOVA) analysis of variance were used to estimate the variation within- and between populations and a discriminant analysis was performed to examine the structure of the between-population differences. The values of particular morphological traits found in our study did not differ considerably from the values reported elsewhere. The results revealed significant within- and between population variation. Variation within populations was highly significant for all the scored leaf morphological traits, while variation between populations was significant for all the studied traits except for the leaflet length. The discrimination between the three populations was significant. High percentages of correctly classified samples demonstrate good discriminating employability of the analysed leaf morphological traits and indicate differentiation of the analysed populations.

Height growth characteristics of one-year-old northern red oak seedlings (Quercus rubra L.) in full light conditions

In this nursery experiment, 100 one-year-old northern red oak seedlings were measured at the end of the 2016 growing season. Measured growth elements were: total height, root collar diameter and total leaf area. All seedlings were classified according to the presence of polycyclism into four types: one-flush growth, two-flush growth, three-flush growth, and four-flush growth type. The number of new flushes (shoots) is a good indicator of total height, root collar diameter and total leaf area.

Italian alder (Alnus cordata/Loisel./Desf.) - new species for allochtonous dendroflora of Serbia.

The foreign tree species, Alnus cordata/Loisel./Desf. (Italian alder), (Betulaceae/Loisel./Duby), not previously recorded in the dendroflora of Serbia, is described in this paper. Italian alder trees in an experimental plot in the area of Erdevik, aged 11 years, show good vitality and fast growth, and bear fruits since their 10th year. Tree heights are in range from 10.4 to 16.2 m, and diameters at the breast height range from14.6 to 34.9 cm. The morphological properties of leaves, fruiting organs (“cones”) and male catkins are in concordance with the values in literature sources, although they show great variability. Since the time of plantation establishment, the absolute minimum air temperature in the nearby meteorological station of Sremska Mitrovica was -26.50C, so it can be assumed that the species is frost hardy. On the basis of the researched properties of Italian alder, it can be concluded that this species can be cultivated in Serbia as an ornamental in urban areas and as a fast growing species in forest plantations for biomass production. [Projekat Ministarstva nauke Republike Srbije, br. 31041: Sumski zasadi u funkciji povecanja posumljenosti Srbije]

Productivity of black locust (Robinia pseudoacacia L.) stands on chernozem in Vojvodina.

This paper presents the elements of growth of black locust trees and stands in 15 sample plots in Vojvodina, at the age of 21-68 years. In each sample plot, based on soil profile horizons the determined soil type was chernozem as well as its lower systematic units (subtype, variety and form), according to the Skoric et al. (1985) classification. On the basis of the mean stand heights (hL), the stands on the subtype of chernozem on loess and loesslike sediments belong to height classes I-IV, and stands on calcareous aeolian sand to classes II-V (according to R e d e i et al. 2014), which indicates their considerable variability with respect to productivity within the determined subtypes of chernozem. Significant differences at the level of chernozem subtypes were found between the mean heights (p = 0.032), but not between the mean diameters (p = 0.083). The mean diameters at breast height in the studied black locust stands were on average lower than the models of diameter growth for the appropriate height classes and determined by a larger number of trees per hectare than in the tables (R e d e i et al, 2014). The volume per hectare is higher than in the tables also being conditioned by the large number of trees per hectare. [Projekat Ministarstva nauke Republike Srbije, br. III43007: Istraživanje klimatskih promena na životnu sredinu: pracenje uticaja, adaptacija i ublažavanje]

Pecan (Carya illinoinensis/Wangenh./K. Koch): A new species of the Allochthonous dendroflora in Serbia

This paper presents the alien species Carya illinoinensis (Wangenh.) K. Koch, carya-pecan, (Juglandaceae A. Richard ex Kunth) that has not been mentioned so far in the dendroflora of Serbia. One tree was recorded within the first Serbian sugar factory in Cukarica that is now a protected cultural property in the City of Belgrade. The tree is about 35 years old and about 20 m high. The length of the trunk without branches is 6.0 m and the diameter at breast height is 57 cm. Carya-pecan is a native species of the southeastern part of North America, and is grown in Europe for edible fruits and quality wood. The recorded tree in Belgrade is fruitful and characterized by good vitality and rapid growth. Due to its special characteristics, it can have multiple practical application in the territory of Serbia for decoration in urban areas, for forest plantations and in orchards. [Projekat Ministarstva nauke Republike Srbije, br. 31041: Sumski zasadi u funkciji povecanja posumljenosti Srbije]

Height growth characteristics of one-year-old pedun­culate oaks on regeneration areas with and without fungicide protection against oak powdery mildew (Microsphaera alphitoides Griff. et Maubl.)

Height growth characteristics of one-year-old pedunculate oaks were studied during three calendar years on comparative regeneration areas both with and without fungicide protection against oak powdery mildew (Microsphaera alphitoides Griff. et Maubl.). Three fungicides were used for the chemical protection of one-year-old pedunculate oaks: Microthiol special, Stroby DF and Anvil. The experiments were located in different site and stand conditions, and the growing seasons in which pedunculate oak seedlings were established were characterized by different precipitation sums and higher air temperatures when compared to multiannual average. The study sample included 1126 plants, and their shoot lengths were measured at the end of the growing season. In the analyzed sample, the second growth stage was recorded on 92.3%-100% of the treated plants and on 69.5%-100% of the untreated plants, the third growth stage was recorded on 52.6%-87% of the treated plants and on 42.1%-82% of the untreated plants, and the fourth growth stage was observed on 0%-37% of the treated plants and on 1.1-29% of the untreated plants. In the analyzed sample, the mean heights of one-year-old pedun-culate oaks were greater on the areas with fungicide protection, but the differences in the percentages of polycyclic growth and the differences in average lengths of individual flushes were not always statistically significant, when compared to the areas without protection, especially after the first stage. The study shows that the dominant effect on the percentage of the second, the third and the fourth stages and on their mean lengths was exerted by site and stand conditions, and that the effects of fungicide protection should be analyzed taking into account the polycyclism of pedunculate oak, i.e. the characteristics of polycyclic growth, which are the resultant of all the effects. In the studied conditions, the fifth stage of growth was recorded in five plants.

Structural and productive-developmental characteristics of white willow plantations of different density on humogley in Donji Srem

The study was conducted in two plantations of white willow (Salix alba L.) in Donji Srem on the humogley soil type (hydromorphic black soil), which belongs to a narrow-leaved ash forest with remote sedge (Carici remotae - Fraxinetum angustifoliae Jov. et Tom., 1979). The plantations are located in the same depression. The SP (sample plot)-1 plantation is 21 years old with a 6×6 m planting spacing, and the SP-2 plantation is 27 years old with a 3×3m planting spacing. Elements of stem growth in the SP-1 plantation showed that with the white willow planting spacing of 6×6 m and a planned 25-year production cycle it is possible to obtain about 250 m3•ha-1 of timber volume, with an 80% net share of technical wood and a 20 % share of pulp wood. The plantation in SP-2 is at the age, which is well above the optimum age in terms of rational management, and the total volume at the age of 27 years is about 300 m3•ha-1, with a 53.7% net share of technical wood and a 46.3% share of pulpwood. [Projekat Ministarstva nauke Republike Srbije, br. 43007: Istraživanje klimatskih promena na životnu sredinu: pracenje uticaja, adaptacija i ublažavanje]

Growth models of black poplar trees, section Aigeiros (Duby)

Different courses of tree growth in height and diameter in nursery and plantation, immediately after transplanting, cause the difficulties in adaptation of tree growth models. Tree growth models, which do not include the sudden transitions and specificities of nursery growth and in the first years after planting can show errors in the assessment of the values of current and average increment at the moment of culmination and at the age of maximum increment. This paper proposes the introduction of additional parameters in the models of diameter and height growth, e.g. the values of mean diameter at breast height and mean height immediately after planting. Compared to the models without additional parameters, the precision of diameter and height model is reflected in the lower standard error of regression (se) and in the more accurate assessment of current and average increment at the moment of culmination and at the age of culmination.