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Tree dieback is a complex process involving negative impact of various abiotic, biotic and anthropogenic factors. Climate change, comprising all those effects, is generally considered as the largest threat to forest ecosystems in Europe. Although the scale of climate change impacts on forests is not yet fully understood, especially on the regional or species level, significant damage seems to be caused by weather extremes, such as drought and strong winds. With the expected increase in the number, length, and/or intensity of extreme weather events in Croatia, research into the causes of tree mortality is both important and timely.Silver fir is the most damaged and endangered conifer tree species in Croatia. The dieback of silver fir can be attributed to various factors, therefore the goals of this research were to determine the mortality of silver fir trees (by number and volume) for various causes of mortality, among which the climatic and structural parameters were of most interest. The twenty-year data for tree mortality in pure silver fir stands in the area of Fužine (Gorski kotar, Croatia) were collected and analysed. The largest number and volume of dead trees was caused by complex (multiple causes) dieback in the overstorey (0,75 N/ha, 2,35 m3/ha), and the smallest (0,17 N/ha, 0,02 m3/ha) by dieback of supressed trees. No significant differences were determined regarding the timing of tree death for different causes of mortality. Climatic parameters (drought, air temperature, PET) and structural parameters of the stands (tree DBH, social position, crown diameter, shading, physiological maturity) as well as plot inclination were found to be the factors of a significant influence on the mortality of silver fir trees., Obična jela najoštećenija je i najugroženija vrsta crnogoričnog drveća u Republici Hrvatskoj. Odumiranje stabala obične jele pripisuje se različitim uzročnicima, stoga je cilj ovog istraživanja bio utvrditi mortalitet stabala obične jele po broju stabala i volumenu za različite skupine uzroka mortaliteta, među kojima su najvažniji bili klimatski i strukturni parametri. Prikupljeni su i analizirani podaci o mortalitetu stabala obične jele u čistim jelovim sastoji­nama na području Fužina (Gorski kotar, Hrvatska) u razdoblju od dvadeset godina. Prema iznosu mortaliteta sta­bala iskazanom u broju stabala najveći mortalitet uzrokovan je kompleksnim odumiranjem stabala (0,75 N/ha) ugornjem sloju sastojine, a najmanji mortalitet uzrokuje prirodno izlučivanje potisnutih stabala (0,17 N/ha). S obzirom na drvni volumen najveći mortalitet uzrokovan je kompleksnim odumiranjem stabala (2,35 m3/ha), a najmanji prirodnim izlučivanjem (0,02 m3/ha). Nisu utvrđene velike razlike u vremenu odumiranja stabala prema različitim skupinama uzroka odumiranja. Klimatski uvjeti (suša, temperatura zraka, PET), strukturni elementi sastojine (prsni promjer, socijalni položaj, promjer i osvjetljenost krošnje te fiziološka zrelost), kao i nagib terena znatno utječu na mortalitet stabala obične jele.

Maquis and garrigue are the most common degradation stages of Holm oak forests in Croatia. Disorganized and uncontrolled cutting degrades forests and changes their microclimates. Measurements were conducted in a Holm oak forest in the maquis and garrigue degradation stages, and in an Aleppo pine forest with Holm oak. The highest variations of microclimate elements were measured in the degradation stages of Holm oak. The average air and soil temperatures, precipitation, and potential evapotranspiration were highest in the garrigue stage and lowest in the maquis stage. The average volumetric soil water content was highest in the maquis stage (14.28%) and lowest in the garrigue stage (9.46%). The dry season water deficit was highest in the garrigue stage (-73.95 mm) and lowest in the maquis (-60.38 mm). Microclimate conditions in the garrigue degradation stage are less favorable for the growth and development of Holm oak than in high forest stands. The average values of microclimate elements in the Aleppo pine forest stand with Holm oak were within the average range of the microclimate elements of garrigue and maquis., Hrast crnika (Quercus ilex L.) je temeljna autohtona šumska vrsta eumediteranskog područja Hrvatske. Hrast crnika pridolazi u svim uzgojnim oblicima i degradacijskim stadijima, a makije i garizi su najčešći degradacijski stadiji crnikovih šuma. Nekontroliranim sječama sastojina sjemenjača i njihovim prevođenjem u degradacijske stadije, mijenjamo mikroklimu određene sastojine. Mikroklimatska istraživanja obavljena su na području otoka Mljeta. Mjerenja su obavljena u šumi hrasta crnike, u degradacijskim stadijima makija i garig te u šumi alepskog bora s hrastom crnikom. Tijekom dvije godine mjerena je temperatura zraka (°C), temperatura tla (°C), oborine (mm), relativna vlaga zraka (%) te volumetrijska vlaga tla (%). Potencijalna evapotranspiracija je izračunata prema metodi Blanea i Criddle. Vodni deficit tijekom sušnog perioda izračunat je kao razlika mjesečne količine oborine (mm) i potencijalne evapotranspiracije (mm). Najveća kolebanja mikroklimatskih elemenata su izmjerena u degradacijskim stadijima hrasta crnike. Najveća apsolutna maksimalna temperatura zraka izmjerena je u stadiju garig, a najveća minimalna u stadiju makije.Prosječne vrijednosti temperatura zraka i tla, oborine i potencijalne evapotranspiracije su bile najveće u stadiju gariga, a najmanje u stadiju makije. Prosječna vrijednost relativne vlage zraka je imala najveću vrijednost u visokoj šumi hrasta crnike. Prosječna volumetrijska vlaga tla je bila najveća u makiji (14,28 %), a najmanja u stadiju gariga (9,46 %). Vodni deficit u sušnom peridou bio je najveći u stadiju gariga (-73,95 mm), a najmanji u stadiju makije (-60,38 mm). Mikroklimatske prilike u degradacijskom stadiju gariga su nepovoljne za rast i razvoj hrasta crnike u odnosu na mikroklimatske prilike u sastojini visokog uzgojnog oblika. Prosječne vrijednosti mikroklimatskih elemenata u sastojini alepskog bora s hrastom crnikom bile su između prosječnih vrijednosti mikroklimatskih elemenata sastojine gariga i makije. Analiza ovih podataka mikroklime služi boljem poznavanju ekoloških prilika šumskih staništa.

Usluge šumskih ekosustava i funkcije šuma imaju slično značenje, iako se djelomično razlikuju. Funkcije šuma se odnose na namjenu i svrhu šuma od kojih ljudi imaju koristi, dok su usluge šumskih ekosustava posljedice i rezultati funkcija šuma, odnosno koristi od ekosustava za čovjeka i okoliš. Usluge šumskih ekosustava se odnose na sve funkcije šuma, dok se općekorisne funkcije šuma (OKFŠ) odnose samo na one funkcije šuma od kojih svi ljudi imaju koristi. Park šuma Marjan (PŠM) sa svojim različitim ekosustavima pruža brojne usluge i koristi stanovnicima Splita, posjetiteljima park šume i drugim organizmima.U Park šumi Marjan koja je površine od oko 300 ha, najzastupljeniji su šumski ekosustavi koji zauzimaju 2/3 park šume. U radu je po prvi puta definirano 28 usluga šumskih ekosustava PŠM na temelju međunarodne podjele usluga ekosustava i drugih podjela OKFŠ. Pomoću anketnog upitnika napravljeno je rangiranje tih usluga. Pet najvažnijih usluga šumskih ekosustava bile su stvaranje čistog i svježeg zraka, pružanje prirodnog prostora za rekreaciju, pružanje prirodnog prostora za odmor, stvaranje kisika i pružanje prirodnog prostora za edukativne aktivnosti. Procjena novčanih vrijednosti pet najvažnijih usluga šumskih ekosustava napravljena je na temelju određenih kriterija i indikatora. Procijenjene vrijednosti pojedinih najvažnijih usluga šumskih ekosustava iznosile su od 700 do 77.000 kn po hektaru godišnje. Procijenjena ukupna vrijednost pet najvažnijih usluga šumskih ekosustava iznosila je 122.000 kn po ha godišnje, odnosno oko 24,4 milijuna kn godišnje za 200 ha šuma PŠM. Napravljena je i aproksimativna procjena vrijednosti preostalih 23 usluge šumskih ekosustava PŠM. Ukupna procijenjena vrijednost svih 28 usluga šumskih ekosustava PŠM iznosila je oko 708.000 kn po ha godišnje, odnosno oko 141,6 milijuna kn godišnje za 200 ha šuma PŠM. Analizirane su i vrijednosti općekorisnih funkcija šuma dobivene na temelju procjene općekorisnih funkcija šuma prema programu gospodarenja za PŠM, zatim na temelju procjene općekorisnih funkcija mediteranskih šuma i na temelju godišnjeg iznosa naknade za općekorisne funkcije šuma. Procjene su iznosile od 200 kn do 402.000 kn po ha godišnje. Procjene novčanih vrijednosti usluga ekosustava, pa tako i šumskih ekosustava, imaju važnu ulogu u planovima zaštite, upravljanja i gospodarenja ekosustavima, kao i pri smanjivanju nepovoljnih ljudskih utjecaja na ekosustave i njihove usluge o kojima ovisi blagostanje sadašnjih i budućih generacija., Forest ecosystem services and forest functions have similar meaning with partial differences. Forest functions refer to forests’ purposes beneficial to people, while ecosystem services are results of forest functions and still present the benefits of ecosystems to people and environment. Ecosystem services cover all forest functions, whereas non-market forest functions are those which are used by all people. Park forest Marjan with its many ecosystems offers many services and benefits to the inhabitants of Split, park forest visitors and other organisms. Of the 300 ha area of park forest Marjan, forest ecosystems are most prevalent and account for 2/3 of the park forest area. In this paper, 28 forest ecosystem services of park forest Marjan were defined for the first time based on the international ecosystem services classification and other non-market forest function classifications. Services were ranked by means of a questionnaire of stakeholders. The five most important services were the production of clean and fresh air, natural space for recreational activities, natural space for leisure, oxygen production and natural space for educational activities. Monetary value of the five most important services was assessed using several different estimation methods based on certain criteria and indicators. Estimated values of individual most important services ranged from 700 kuna to 77.000 kuna per ha per year. Total estimated value of those services amounted to 122.000 kuna per ha per year, that is, 24,4 million kuna per year for the 200 ha of forests in park forest Marjan. Furthermore, approximative monetary value assessment was performed for other 23 forest ecosystem services. As a result, the total estimated value of all 28 services was 708.000 kuna per ha per year, that is, around 141,6 million kuna per year for the 200 ha of forests in park forest Marjan. Obtained results were validated using assessment of non-market forest functions according to the management plan of park forest Marjan, assessment of non-market forest functions of mediterranean forests and the annual amount of non-market forest function fees, with estimated values ranging from 200 kuna to 402.000 kuna per ha per year. Monetary assessment of forest ecosystem services is key in the management and protection of ecosystems, as well as in reducing of adverse human influences on ecosystems and their services, which serve to the welfare of current and future generations.

Pojava odumiranja stabala hrasta lužnjaka (Quercus robur L.) i poljskog jasena (Fraxinus angustifolia Vahl) gospodarski je i ekološki problem. Čimbenici koji uzrokuju odumiranje stabala mogu biti biotski, stanišni i strukturni odnosno sastojinski.Istraživanje je provedeno u gospodarskoj jedinici „Zelenika” u Posavini. Ciljevi ovog istraživanja bili su utvrditi prosječnu stopu promjene intenziteta odumiranja stabala hrasta lužnjaka i poljskog jasena, istražiti utjecaj stanišnih i strukturnih čimbenika na intenzitete odumiranja te usporediti intenzitete odumiranja hrasta lužnjaka i poljskog jasena prema dobnom razredu sastojina i mikroreljefu. Za analizu su korišteni podaci o klimi za meteorološku postaju Novska, vodostaju vodotoka Novska te podaci o razinama podzemne vode sa pjezometarske postaje „Zelenika“. Iz obrazaca O-2 Osnove gospodarenja, prikupljeni su podaci o volumenu odumrlih stabala hrasta lužnjaka i poljskog jasena te podaci o strukturnim čimbenicima. Intenziteti odumiranja izračunati su na temelju odnosa volumena odumrlih stabala po jedinici površine. S obzirom na prosječnu stopu promjene, intenziteti odumiranja hrasta lužnjaka i poljskog jasena se povećavaju. Najveći intenziteti odumiranja za obje šumske vrste su u sastojinama VI. dobnog razreda. Na osnovi provedenih istraživanja možemo zaključiti da klimatski, hidrološki i strukturni čimbenici imaju utjecaj na odumiranje hrasta lužnjaka i poljskog jasena. Hrast lužnjak osjetljiviji je na klimatske elemente u odnosu na poljski jasen. Pojava sušnih i izostanak kišnih razdoblja također značajno utječe na odumiranje. Smanjenje srednjega minimalnog vodostaja vodotoka utječe na odumiranje hrasta lužnjaka, dok smanjenje maksimalnog vodostaja vodotoka utječe na odumiranje poljskog jasena. Na intenzitete odumiranja značajno utječe pad razine podzemne vode u dubljim slojevima pedosfere. Svi strukturni čimbenici utječu na odumiranje hrasta lužnjaka, dok na odumiranje poljskog jasena značajno utječe jedino povećanje obrasti i broja stabala u sastojini., The pedunculate oak (Quercus robur L.) and narrow-leaved ash (Fraxinus angustifolia Vahl) tree dieback phenomenon presents an economic as well as ecologic problem. Factors that cause tree dieback can be biotic, biotopic (within habitat) and structural (within stand). In managed forests, the volume of dead trees or volume of trees cut in a sanitation harvests are most often used to show the intensity of tree dieback, and may also be used as an indicator of the stands condition (Capecki, 1981).Every species has its own ecological niche. Forest tree species have varying reactions to changes in environmental factors, to stress and ultimately to dying. The study was conducted in „Zelenika” management unit in Posavina. The aims of the study were to establish pedunculate oak and narrow-leaved ash tree dieback dynamics, to research the influence of biotopic and structural factors on dieback intensity and to compare dieback intensities according to the stand age class and microrelief. For analysis were climatic data for Novska meteorological station, water level data of Novska watercourse, and groundwater level data from „Zelenika” piezometric station were used. Dry years and dry periods, and wet years and wet periods, were determined using the percentile method and the Walter climate diagrams.Growing volume of withered pedunculate oak and ash trees, as well as structural factors data(stand structure elements) were collected from the O-2 form of the Forest management plan. Dieback intensities were calculated on the basis of growing volume of the withered trees per area unit ratio. The intensity of tree death was shown in absolute numbers, as m3/ha (Siwecki et al. 1998).Considering the average change rate, dieback intensities of pedunculate oak and narrow-leaved ash tree are increasing. The highest dieback intensities for both forest species were found in the VI age class (Figure 2). On the basis of the conducted research, it can be concluded that climatic, hydrological and structural factors influence pedunculate oak and narrow-leaved ash tree dieback.Pedunculate oak is more sensitive to climatic elements in comparison to narrow-leaved ash tree. Frequent dry years significantly affected the dying of these two species, which can both be considered hydrophytes in terms of their ecological demand for water. The results of this study showed that narrow-leaved ash was more vulnerable to drought than pedunculate oak.Drought and rain periods also significantly influence tree dieback (table 5). The effect of dry periods on the dieback of these two species was greater in relation to the lack of wet periods in these lowland forests. The decrease of mid and minimal water levels of watercourse influenced pedunculate oak dieback, while a decrease of maximum watercourse water levels influenced narrow-leaved ash tree dieback (table 6). Groundwater level decrease in deeper layers of pedosphere had asignificant influence on tree dieback intensities (table 7). It was revealed that all structural factors influence pedunculate oak dieback, while narrow-leaved ash tree dieback was influenced only by stocking and tree number increase in a stand (table 8).The dieback of pedunculate oak was higher in older stands. No correlation was detected between the dieback of narrow-leafed ash and stand age.

Obična jela (Abies alba Mill.) je najoštećenija vrsta šumskog drveća u Republici Hrvatskoj. Kao posljedica promjene prirodnih stanišnih čimbenika javlja se propadanje i iznenadno odumiranje njezinih stabala. Zbog intenzivnog odumiranja stabala dolazi do prekida sklopa i stvaranja manjih ili većih šumskih otvora. Takve pojave izazivaju promjenu mikroklimatskih i mi­krobioloških uvjeta te probleme kod pomlađivanja. Istraživanja su provedena u Gorskom kotaru, u području bukovo-jelovih i jelovih šuma. Osnovni cilj istra­živanja bio je utvrditi promjene kemijskog i mikrobiološkog sastava tla šum­skih otvora, te prirodno pomlađivanje na njima. Obavljene su kemijske i mikrobiološke analize šumskog tla. Mikrobiološke analize tla obuhvaćale se određivanje broja bakterija i gljiva, kao i zastupljenost funkcionalnih skupina mikroorganizama. Prema kemijskim pokazateljima utvrđene su veće vrijedno­sti u kontrolnim plohama (šumska sastojina) u odnosu na velike šumske otvore. Iznimka je bio mali šumski otvor, gdje su vrijednosti kemijskih varijabli tla bile veće u otvoru nego na pripadajućoj kontrolnoj plohi. U pogledu zastupljenosti pojedinih funkcionalnih skupina mikroorganizama mali šumski otvor ima sre­dnju biogenost tla, dok veliki otvori imaju slabu biogenost tla. U velikom ot­voru u šumi bukve i jele utvrđen je manji broj aerobnih asimbiotskih fiksatora dušika i celulolitičkih gljiva u odnosu na kontrolnu plohu. Mali otvor u šumi bukve i jele imao je veću zastupljenost pojedinih funkcionalnih skupina mi­kroorganizama tla u odnosu na pripadajuću kontrolnu plohu, osim celuloliti­čkih gljiva. Najveća biogenost tla utvrđena je u malom otvoru. U velikom otvoru u šumi jele s rebračom u odnosu na kontrolnu plohu utvrđen je značajno manji ukupan broj gljiva i celulolitičkih gljiva. S obzirom na brojnost starijih biljaka utvrđena je dobra pomlađenost listopadnim vrstama drveća unutar samih otvora i to gorskim javorom i običnom bukvom., Silver fir (Abies alba Mill.) is the most damaged forest tree species in Republic of Croatia. As a result of changes in natural biotope fac­tors tree degradation and sudden decline is manifested. Intensive tree decline leads to canopy degradation and creating smaller or larger forest gaps. These advents cause changes in microclimatic and microbiological conditions, and regeneration problems. Researchers are carried out in Gorski kotar, in beech-fir and fir forest areal. The main aim of this research was to determine chan­ges in chemical and microbiological composition of forest gap soil, and natural regeneration within gaps. Chemical and microbiological analyses of forest soil were done. Soil microbiological analyses included determination of total fungi and bacteria count, and presence of microorganism functional groups. According to chemical parameters higher values were found in con­trol plots (canopy) than in large forest gaps. Exception was small forest gap where values of chemical variables were higher than in corresponding control plot (table 2). In large beech-fir forest gap was found smaller number of asymbiotic nitro­gen fixators and cellulose decomposition fungi than in control plot (table 3). Small forest gap in beech-fir forest had higher value of individual soil functional microorganism groups than corresponding control plot, except cel­lulose decomposition fungi. The highest soil biogenity was found in small fo­rest gap (table 4). In large fir with hard fern forest gap regarding control plot was found si­gnificantly smaller total fungi count and amount of cellulose decomposition fungi (table 5). Comparing gaps between themselves total fungi count in O1 and O2 beech-fir forest gaps was significantly higher than in O3 fir with hard fern gap. Amount of asymbiotic nitrogen fixators and ammonia forming bacteria was significantly the highest in small gap O2, then in large gap O1 in beech-fir forest, and the lowest in O3 fir with hard fern forest gap (table 6). Amount of asymbiotic nitrogen fixators, cellulose decomposition fungi and ammonia forming bacteria was significantly higher in beech-fir forest than in fir with hard fern forest (table 7). The highest number of seedlings was found in gap O1, while other two gaps have had equal plant number. Regarding control plots gap O1 had two times more plants than control. In gap O2 was found two times lower plants number regarding control, while gap O3 had equal plants number as control. Considering plants age in all gaps and control plots was found the highest number of biennial plants (table 8). Considering percentage of tree species younger than three years, in gaps was found the highest proportion of silver fir, then mountain maple, and the lowest common beech (table 9). Considering the number of older trees good regeneration with deciduous tree species was found within gaps namely with mountain maple and common beech (tables 10, 11 and 12). Considering amount of different functional microorganism groups small forest gap O2 has medium, while large gaps have lower soil biogenity. Com­paring large gaps in different forest associations, large gap O1 in beech-fir fo­rest regarding large gap O3 in fir with hard fern forest has significantly higher total fungi count, amount of asymbiotic nitrogen fixatros and ammonia for­ming bacteria. In this research was found different amount of soil individual microorganism groups comparing beech-fir forest and fir with hard fern fo­rest. As in larger forest gaps were found certain changes in soil microbiologi­cal characteristics regarding small gap it can be concluded that large gaps represent specific microbiotops. Namely in forest gaps are found young silver fir plants, while there is lack of older ones. According to height in gaps there are no silver fir plants higher than 50 cm. As large forest gaps are enlarging and not getting smaller, also are good regenerated with common beech and mountain maple plants, were are believe that forest gaps are biotops with exc­hanging tree species. Soil chemical characteristics in small beech-fir forest gap had higher va­lues, and large gap lower values than control plots. Soil chemical characteri­stics in large fir with hard fern gap had smaller values than in control plots, except soil pH value. In all gaps was found significantly lower amount of cel­lulose decomposition fungi than in control canopies. In large forest gaps was found low, and in small forest gap medium soil biogenity. Microbiological characteristics of soils in beech-fir forests have higher values than in fir with hard fern forest gaps. Proportion of deciduous tree species (mountain maple and common beech) younger than three years was higher in large beech-fir forest gap, while in small gap was same. In large fir with hard fern forest gap dominate silver fir plants younger than three years. According to number of plants younger than three years in forest gaps and control plots are dominating mountain maple and common beech plants, while proportion of silver fir plants was small.

Obična jela jedna je od najvažnijih gospodarskih vrsta drveća u Hrvatskoj. Rasprostranjena je na području Dinarida i na panonskom gorju. Globalne klimatske promjene izazivaju opravdanu bojazan u mogućnost sma njenja ekološke niše obične jele u Hrvatskoj. U ovom su istraživanju analizirani određeni ekološki čimbenici koji izgrađuju ekološku nišu unutar područja pridolaska jele. Korišteni globalni klimatski model podrazumijeva dvostruko povećanje koncentracije stakleničkih plinova (CO2, CH4, N2O, CFC-11 i CFC-12) unutar da našnjega areala obične jele u razdoblju 2000 – 2100. godine, iz čega proizi la zi povećanje prosječne godišnje temperature za ~ 2,5 °C i smanjenje prosječ ne godišnje količine oborina za ~ 152 mm/god. u odnosu na razdoblje 1950 – 2000. godine. Istraživanje je pokazalo kako bi ove promjene mogle pro uzročiti smanjenje ekološke niše obične jele u Hrvatskoj (p>0,9) za gotovo 85 % u odnosu na današnje stanje., The aim of this research is to determine the following: the fundamental ecological niche or potential distribution range of silver fir in Croatia on the basis of selected climatic factors, differences between parts of fir distribution range with reference to the selected climatic factors and changes in the ecological niche in terms of the climate change model for the period 2000 – 2100. Climatic data for the period 1950 – 2000 used in this work were taken from the Worldclime database (Hijmans et al. 2005). Eight climatic variables and relief factors were employed to construct the prognostic model, such as altitute (m), slope (°) and others. Highly correlated variables were rejected. To predict climate changes for the period 2000 – 2100, a CCM3 model (Climate Change Model) was used, which is based on double the current level of greenhouse gases (CO, CH 4, N2O, CFC-11 and CFC-12) (Govindasamy et al. 2003). All climatic data in grid form were 2entered in 30-second resolution (~ 1 km2). Data on fir occurrence in Croatia were taken from the latest research on the distribution of forest sites (Vukelić et al. 2008), ICP plots, phytocoenological relevé database of the Republic of Croatia and management plans. In each plot fir occurrence was graded with binary variables – 1 (present) and 0 (absent). Independent variables used to construct the logistic model and prediction included elevation – Elev (m), slope – Slope (°), mean annual temperature – MeanAnnT (°C), mean annual temperature range – MeanAnnTR (°C), obtained as the difference between the mean temperature of the warmest and the coldest month, then the ratio between the mean monthly temperature range and the mean annual temperature range – IsoTherm (°C), mean temperature of the driest quarter - MeanTDQ (°C), mean temperature of the coldest quarter – Mean TCM (°C), mean annual precipitation quantity – MeanAnnP (mm), mean annual precipitation in the warmest quarter – MeanPWQ (mm) and coefficient of seasonal precipitation variation – PreS (mm). The distribution range of fir was divided into three parts: DIN – the Dinaric part of fir range within the community Omphalodo-Fagetum /Tregubov 1957/ Marinček et al. 1993, ACD – the Dinaric part of acidophilic fir communities (Blechno-Abietetum Horvat /1938/ 1950) and PAN – the Pannonian part encompassing fir range within the community Festuco drymeiae-Abietetum (Vukelić et Baričević 2007). Discriminant analysis (DA) was used to analyze and visualize ecological niches within the range. The prognostic model of ecological niches for the current distribution range of fir and that for the period until 2100 with regard to climate change model was made by means of logistic regression (LOGREG), expressions: p(y)= exp(LP)/(1+exp(LP)), where LP represents linear combination of independent variables (Flantua et al. 2007). According to the research, the current range of silver fir in Croatia does not differ dramatically (p . 0.9) from the potential one. This suggests that longlasting forest management did not contribute to its reduction. However, the selected climatic factors could have a signficant effect on the occurrence of silver fir in Croatia. The prognostic model shows that in conditions of global climate changes its potential range (p = . 0.9) in Croatia could decrease by ~ 85% in the period 2000 – 2100.

Pojava propadanja i odumiranja stabala hrasta lužnjaka jedan je od najznačajnijih gospodarskih i ekoloških problema u šumarstvu Hrvatske. Gospodarski problemi odnose se na smanjenje kakvoće drva, poremećaje u potrajnom gospodarenju te povećanje troškova gospodarenja i smanjenje prihoda. Ekološki problemi odnose se na stalne promjene stanišnih uvjeta i smanjenje stabilnosti šumskih ekosustava. Cilj istraživanja bio je analizirati iskorištenje drvnog obujma različito oštećenih stabala hrasta lužnjaka. Prosječna osutost stabala uz cestu Županja - Lipovac iznosila je 57 %, a na području spačvanskih šuma 24 %. Utvrđeno je intenzivno odumiranje sta bala hrasta lužnjaka uz cestu Županja-Lipovac u 2003. godini, koje je iznosilo 30 %. U svim stupnjevima osutosti utvrđena su stabla s biotskim oštećenjima. Kod stabala sa značajnom osutošću krošanja (>25 %) utvrđeno je smanjenje udjela tehničkog drva za oko 10 %, odnosno isto toliko povećanje otpada. Udio furnirskih trupaca kod stabala male i srednje osutosti bio je 50 % veći u odnosu na jako osuta i odumrla stabla. U radu je raspravljena problematika ukupnog iskorištenja drva pri sječi i izradbi te vrijednost drvnih sortimenata vitalnih stabala u odnosu na oštećena i odumrla stabla hrasta lužnjaka., Management with forests of pedunculate oak, the principal commercial tree species in Croatia, is burdened with increasing instances of tree decline and dieback. A combination of factors, such as decreased height and diameter increment, lower value of wood assortments, disturbances in planning and management and rising management costs, have made this the most important management and ecological problem in Croatian forestry. Tree decline is a gradual, continuous, or in some cases, rapid loss of tree vita lity. In forestry, tree decline is assessed on the basis of the exterior appearance of a tree, i.e. on the basis of tree damage assessment. Tree damage relates to crown, stem and root damage. Crown damage assessment is based on crown defoliation and changes in leaf colour. Tree dieback is sudden death of trees due to diseases or a complex action of adverse factors. It can often stem from a continuous decline of trees and a disturbed stability of forest ecosystems. In Croatia, the most severely affected tree species are the two principal ones: pe dunculate oak and silver fir. Tree decline and dieback incur high financial los ses, amounting to as much as 40 % of the potential market value of forest assortments. However, a decrease in non-market forest functions is much more serious. The economic consequences of tree decline are reflected on the quality and lower value of wood assortments. Dieback of pedunculate oak trees leads to sapwood degradation and a decrease in assortment diameter, which may amount to as much as 33 % of the diameter. The goal of research was to determine the impact of pedunculate oak da mage on the structure and volume of wood assortments. Research was con ducted on tree samples from four management units in Vinkovci ForestAdministration, along the Županja - Lipovac road. Wood volume utilization of dead and differently damaged trees of pedunculate oak was analyzed. Tree crowns along the Županja - Lipovac road were found to be more defo liated compared to those in the “Spačva basin” area. Crown defoliation of pe­dunculate oak was about 60 %, which indicates decreased tree vitality. Severely defoliated and dead trees manifested significantly higher biotic da mage in relation to slightly and moderately defoliated trees. The percentage share of veneer logs and class I logs, as well as stacked wood, was higher in trees with the first and second defoliation class. The share of lower class logs (II and III class), as well as the percentage share of waste was higher in trees with higher defoliation classes. Of the total wood volume, there were 20 % of veneer logs in defoliation classes 1 and 2 (slight and moderate defoliation), and 10 % of veneer logs in defoliation classes 3 and 4 (severe defoliation). Ac cording to the percentage share of assortments in the total technical roun dwood, there were 37 % of veneer logs in trees with defoliation classes 1 and 2, and 18 % of veneer logs in defoliation classes 3 and 4. The proportion of lower-class technical assortments was higher in higher classes of crown defo liation. The proportion of second class logs in defoliation classes 1 and 2 was 11 %, and in defoliation classes 3 and 4 it was 19 %. The proportion of third class logs in defoliation classes 1 and 2 was 15 %, while in defoliation classes 3 and 4 it reached 19%. There was more waste in defoliation classes 3 and 4 (30 %), and slightly less in defoliation classes 1 and 2 (27 %). Tree damage lowers the quality of logs and lessens the income from pedun culate oak management. Tree damage assessment may reduce the amount of snags and increase management yields. Timely and appropriate tree damage assessments have a positive effect on overall management with pedunculate oak. The selection of damaged trees for felling is a key factor that ensures the quality of the wood matter in disturbed and unstable forest ecosystems.