Knowledge on the range of variability of montane European forests is hampered by limited data on the natural disturbance regime and by the small size of old-growth remnants. We studied the mixed Fagus – Abies – Picea Lom forest reserve (55.8 ha) in Bosnia and Herzegovina at three different scales: a grid of 40 sampling points to describe the structural characteristics and their range of variability, three transects to analyse gap size and gap fraction, and a 1.1 ha permanent plot to reconstruct age structure and disturbance history. The forest is characterized by a high volume of living trees (763 m3·ha–1 in the 55.8 ha core area and 1160 m3·ha–1 in the permanent plot) and of coarse woody debris (327 and 383 m3·ha–1, respectively). The percentages of forest area in canopy and expanded gaps are 19% and 41%, respectively. The median canopy gap size is 76.9 m2 and ranges from 11.1 to 708.0 m2. There are large (up to 120 cm diameter at breast height) and very old trees (441, 432, and 416 years for silver fir ( Abies alba Mill.), Norway spruce ( Picea abies (L.) Karst.), and European beech ( Fagus sylvatica L.), respectively). During the last three centuries, the disturbance patterns have been characterized by single-tree or small group mortality. In central Europe, this forest is at the end of a gradient from forests characterized by intermediate disturbances to those where very small-scale processes predominate.

International audienc

We investigated forest canopy gaps in the mixed beech (Fagus sylvatica L.), silver fir (Abies alba Miller), and Norway spruce (Picea abies (L.) Karst.) old-growth forest of Lom in the Dinaric Mountains of Bosnia and Herzegovina. Gap size, age, gap fraction, gapmaker characteristics and the structure and composition of gapfillers were documented to investigate gap dynamics. The percentages of forest area in canopy and expanded gaps were 19% and 41%, respectively. The median canopy gap size was 77 m 2 , and ranged from 11 to 708 m 2. Although there were many single tree-fall gaps, the majority had multiple gapmakers that were often in different stages of decay, suggesting gap expansion is important at the study site. Of the gapmakers recorded, 14% were uprooted stems, 60% snapped stems, and 26% were standing dead trees. Dendroecological analysis suggests that gap formation varied in time. The density of gapfillers was not correlated to gap size, and the species composition of gapfillers varied between seedling, sapling, and tree life stages. The results suggest that gaps are mainly formed by endogenous senescence of single canopy trees. Exogenous disturbance agents, most likely related to wind and snow, act mainly as secondary agents in breaking weakened trees and in expanding previously established gaps. Although the findings are partially consistent with other studies of gap disturbance processes in similar old-growth forests in central Europe, the observed gap dynamic places the Lom core area at the end of a gradient that ranges from forests controlled by very small-scale processes to those where large, stand replacing disturbances predominate.

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Silver fir (Abies alba Mill.) is the most common conifer species in Bosnia and Herzegovina. The paper describes the development of a silver fir master tree-ring chronology from Kozara National Park and analyzes the influence of the climate conditions on tree-ring widths. The knowledge concerning the effect of climate on cambium activity and, as a result, on tree growth is of great importance for silviculture, which is particularly complex in terms of deterioration of health condition. Four sites were selected for sampling at Kozara National Park. At each sampling site, 15 dominant trees were drilled with Pressler’s increment borer at breast height. The development of chronology included three steps: i) cross-dating of a series of tree-ring width and checking of their quality using the COFECHA program, ii) data standardization in the ARSTAN program, and iii) master chronology development. Correlation analysis was performed in order to determine the links between tree-ring width and climate (primarily temperature and precipitation). In the 88-year-long master chronology, pointer years analysis identified five positive and nine negative years. Correlation analysis revealed that precipitation had stronger and more significant impact on silver fir radial growth, particularly at the beginning of the growing season, in April and May (r=0.175 and r=0.318, respectively), and in the crucial July−September period (r in the range of 0.143−0.222). The highest negative correlation coefficient with temperature was determined for September of the previous year (r=-0.282) and then for summer months (July and August) of the current year (r=-0.184 and r=-0.272, respectively). In addition, statistically significant correlation between radial growth and the Forestry Aridity Index was determined (r=-0.390). The results of tree-ring width climate analysis obtained in this study are in accordance with other studies carried out in Bosnia and Herzegovina and in the surrounding area.

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Posebna vrijednost metoda ure ivanja šuma u Bosni i Hercegovini je što omoguava pra enje stanja šuma, odnosno kontrolu gazdovanja.Apstrakt: Analiza i ocjena gazdovanja šumama u proteklom ure ajnom periodu, kao poglavlje u šumskoprivrednim osnovama, od klju nog je zna aja za održivo gazdovanje. Rezultati naše analize, na uzorku od devet šumskoprivrednih osnova iz Republike Srpske, nedvosmisleno su pokazali formalni karakter izrade ovog poglavlja. Površine ure ajnih jedinica neopravdano trpe stalne promjene. Zalihe se tako e nerealno mijenjaju u toku ure ajnog perioda, a veliki, esto drasti an, pad kvaliteta šuma ostaje neobrazložen. Promjene prirasta tako e nemaju adekvatno obrazloženje, a ne pridaje se potreban zna aj ni analizi otvorenosti šuma. Kod analize realizacije plana sje a konstatovano je više situacija nepoštovanja zakonskih odredbi kako u pisanju ovog poglavlja, tako i u samom gazdovanju šumama. Sli na je situacija sa šumskouzgojnim radovima i zaštitom šuma. Zbog izostanka mjera njege i proreda šumske kulture nestaju. Realizacija šumskih drvnih sortimenata po strukturi je zabrinjavaju e loša. Dok najvrijedniji sortimenti "teže nuli" otpad se pove ava. Investicije i ne postoje. U potpunosti su zapostavljene ostale funkcije i usluge šuma. Ne daje se kriti ka ocjena gazdovanja u proteklom ure ajnom periodu, koja je obavezna u šumskoprivrednim osnovama.Klju ne rije i: šumskoprivredna osnova, analiza gazdovanja šumama, ure ajni period.

Izvod: U radu je prezentovana analiza strukure krošanja u kulturama crnog bora u Tesli kom šumskoprivrednom podru ju. Pet oglednih površina je postavljeno u sastojinama (51-60 godina) koje u dosadašnjem periodu nisu prore ivane, dok je jedna ogledna površina postavljena u sastojini u kojoj su provo ene mjere njege. Na oglednoj površini postavljenoj u sastojini u kojoj su provo ene mjere njege broj stabala po hektaru iznosi 389 a u neprore ivanim sastojinama 1282. Prosje na površina horizontalne projekcije krošnje stabla na oglednoj površini postavljenoj u sastojini u kojoj su provo ene mjere njege je 20,4 m 2 , a u sastojinama koje nisu prore ivane 6,6 m 2 . Prosje na apsolutna dužina krošnje stabla u prore ivanoj sastojini je 13,21 m, a u sastojinama koje nisu prore ivane 7,50 m.Klju ne rije i: crni bor, kulture, proreda, struktura krošanja. CROWN STRUCTURE IN AUSTRIAN PINE FOREST CULTURES IN FOREST MANAGEMENT AREA "TESLI "Abstract: This paper presents analysis of crowns structures in forest cultures of Austrian pine in forest management area "Tesli ". Five plots were set up in the stands (51-60 years old) that has so far not been thinned, and one sample plot is set in a stand that had an adequate silvicultural treatment. In the experimental plot, set in the stand that had an adequate silvicultural treatment, the number of trees per hectare is 389, and in stands that did not have adequate silvicultural treatment is 1282. The average crown projection area on the sample plot, set in the stand that 1 Administrativna služba Opštine Tesli -odjeljenje za inspekcijske poslove sa komunalnom policijom 2 Univerzitet u Banjoj Luci, Šumarski fakultet, S. Stepanovi a 75a, Banja Luka (vojodukic@yahoo.com)