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In today's increasingly difficult living conditions, Narrow-leaved ashes are valuable wood species of our forests that deserve specific care. The difficult possibility of natural regeneration encourages us to find new solutions in production of forest reproductive material intended for management of lowland forests. Overcoming the double dormancy of the Narrow-leaved ash tree seeds is a challenge in the production of forest reproductive material and requires special attention and skill in pre-sowing treatment. Aim of the paper was to determine whether there is a difference between the two pre-sowing methods seeds on the nursery germination. Seeds originated from six different groups: Nova Gradiška, Prvča, Lipovljani, Čakovec, Cetina and clone trees by academic Mirko Vidaković. Pre-sowing tretmants are moist warm and moist cold and stratification at 3°C. Moist warm and moist cold treatment was for 6 weeks at a constant temperature of 20°C and then 16 weeks at a constant temperature of 3°C. The other procedure was stratification at a constant temperature of 3°C for 22 weeks. Quartz sand was used for pre-sowing tretmants. The ratio of seeds and sand was 1:4 with the addition of 37% water. Sowing was done on the May 9th, 2018 on nursery beds. The first seedlings appeared nine days after sowing, and the first counting of the seedlings was done on the 23rd of May, or the 14th day after sowing which represents the germination energy of the seeds. The final count was completed on the 5th of July after the end of germination period of 56 days, exactly as prescribed by ISTA rules for the genus Fraxinus spp. Counting criteria was the occurrence of cotyledons above ground. The results showed that the moist warm and moist cold process increased the total seedling germination by 27.04% compared to the stratification. The germination of seeds from Nova Gradiška, Lipovljani and Čakovec, treated with moist warm and moist cold process, was 38.90% higher compared to the same seeds that were only stratified. On the other hand, the germination of stratified seed from Prvča and Akademic Vidaković clones was 68.90% higher compared to the germination of the same seed, which went through process of moist warm and moist cold.

U radu su prikazani rezultati ispitivanja laboratorijske klijavosti i morfoloških značajki klijanaca europskoga pitomoga kestena (Castanea sativa Mill.). Uzorci za istraživanja sakupljeni su u submediteranskom području Hrvatske, a radni uzorak za ispitivanje klijavosti iznosio je 8×25 sjemenki. Sjeme je do ispitivanja klijavosti čuvano tri mjeseca u hladnjaku na temperaturi od 3 °C. Postotak laboratorijske klijavosti utvrđen je prema postotku pravilnih klijanaca koji su normalno proklijali nakon 27 dana ispitivanja. Ispitivanje je provedeno u laboratoriju prema uvjetima koje propisuje ISTA (International Seed Testing Association). Izrađen je katalog sa slikama i opisom nepravilnih klijanaca. Na osnovi definiranih kodova nepravilnih klijanaca moguće je preventivno djelovati kako bi se reducirale nepoželjne jedinke. Rezultati ovog istraživanja od velike su koristi za razumijevanje složenoga procesa klijanja sjemena, kako u laboratoriju, tako i šumskim rasadnicima., The paper presents the results of laboratory germination testing and morphological characteristics of sweet chestnut (Castanea sativa Mill.) seedlings. The research samples were collected in the sub-Mediterranean region of Croatia, and the working sample for germination testing was 8×25 seeds. Prior to germination testing, the seeds were stored in a refrigerator for three months at 3°C. The percentage of laboratory germination was established according to the percentage of regular seedlings which germinated normally after 27 days of testing. The testing was carried out in a laboratory under the conditions prescribed by ISTA (International Seed Testing Association). A digital photo camera was used to take photos of all abnormal seedlings, which were then catalogued with their pictures and descriptions. The results of this research are very useful for nursery practice and can be applied in producing plants from seeds, rootstocks for grafting, and further raising of seedlings to be grown in plantations.

Fruits of service tree were harvested in the fall of 2018 on 10 trees in the area of Tounj. The aim of the study was to determine the age of the trees and the environmental factors on seed germination of seed and morphology of bare root seedlings 1 + 0. To determine the age of the trees and the dendroecological analyzes, increment cores were taken with the Pressler drill bits. On each individual tree were taken two opposite increment cores on the chest height (d1.30). After the collection of the increment cores, standard processing and mechanical preparation of the samples were made. Prepared samples after processing were lens out using ATRICS system and then processed and analyzed with dendrochronological programs. The values of width of both late and early wood were measured. Chronologies of width of the tree rings are standardized using the RCS method and correlations with climate factors (air temperature and precipitation) have been made. The number of seeds in 1 gram ranged from 21 to 41 pcs, depending on the tree. Prior to stratification the seed was moistened for 24 h in distilled water at room temperature. Seed stratification at a temperature of 3°C was duration for 109 days. As a stratification medium, wet sand (ratio of seeds and sand 1: 4) was used. The sowing was done in ranks in Dunemann's bed 02.04.2019. Seeds from each tree were sown separately and quartz sand was used as a substrate for covering. In the period from 17.04. to 16.05, every week, counting the seed germination. As a counting criterion, there was a cotyledons over the surface of the substrate. The total nursery germination varied with respect to the tree and ranged from 12.27 to 59.11%. From sowing to the end of germination, regular plant care was performed in the Dunemann's bed, which included the protection of damping off of seedlings, which was performed on three occasions with Cuprablau Z, Dithane M-45 and Captan WP 50 fungicides. At the end of the vegetation, the height (cm) and the diameter of the root plant root (mm) were measured.

Sitni glodavci iz podporodica Murinae (pravi miševi) i Arvicolinae (voluharice) nezaobilazna su biotska komponenta zoocenoze lužnjakovih šuma. Unatoč brojnim pozitivnim utjecajima, glodavci mogu u godinama masovne pojave otežati prirodnu obnovu hrastovih šuma uzrokujući štete na sjemenu te stabljici i korijenu mladih biljaka. Na području srednje Posavine (šumarija Lipovljani) u razdoblju od 2011.g. do 2013.g., utvrđen je obujam šteta od sitnih glodavaca u vidu analize oštećenja na stabljici i korijenu hrastova pomlatka starosti do pet godina. Grizotinama na stabljikama oštećenih biljaka (33 komada) izmjerene su dimenzije (dužina x širina), dok je morfološka analiza korijena oštećenih biljaka (115 komada) provedena skeniranjem korijena korištenjem uređaja Epson Expression 10000 XL i programskog paketa WinRhizo, čime su izmjereni duljina i volumen korijena te broj korijenovih vrhova. U cilju usporedbe oštećenog i neoštećenoga korijena, prikupljeno je i na jednak način analizirano 33 komada biljaka neoštećenoga korijena. Razlike u prosječnim vrijednostima analiziranih parametara neoštećenog i oštećenog korijenja testirane su Studentovim t-testom, odnosno u slučaju da uvjet homogenosti varijanci nije bio zadovoljen, neparametrijskim Mann-Whintey U- testom. Na kori stabljika analiziranih biljaka prosječna površina grizotine iznosila je 182, 5 mm2 (16, 5 mm2 - 766, 5 mm2) i to prosječno na 1, 6, a najviše na pet mjesta na stabljici. Hranjenje glodavaca korijenjem lužnjakovog pomlatka značilo je gubitak do 77% volumena korijena, 96% korijenovih vrhova te smanjenje duljine korijena i do 97%. Usporedbom prosječnih vrijednosti volumena, duljine i broja vrhova korijena oštećenih i neoštećenih biljaka, ustanovljeno je da su razlike među njima statistički značajne kod gotovo svih visinskih kategorija biljaka i debljinskih kategorija korijena za koje je provedena usporedba. Ovim je istraživanjem dobiven kvalitativni nalaz šteta od glodavaca na stabljici i korijenu hrastova pomlatka.

Sitni glodavci iz podporodica Murinae (pravi miševi) i Arvicolinae (voluharice) u šumama hrasta lužnjaka (Quercus robur L.) tijekom godina masovne pojave otežavaju prirodnu obnovu šuma uzrokujući štete na sjemenu, stabljici i korijenu mladih hrastovih biljaka. U okviru istraživanja provedenih od 2011.g. do 2013.g. na području šumarije Lipovljani, utvrđena je relativna brojnost glodavaca zajedno sa udjelom dominantnih podporodica u populaciji te njihovim prostornim rasporedom. Analizirane su također štete od glodavaca na stabljici i korijenu lužnjakovog pomlatka, u okviru čega je provedena morfološka obrada oštećenoga i neoštećenoga korijenja te njihova usporedba. Utvrđeno je da pri relativno niskoj brojnosti glodavaca (0-16%) više od petine hrastova pomlatka (22%) može biti uništeno zbog posljedica grizenja korijena, osobito ako u strukturi populacije glodavaca dominiraju voluharice. Nadalje, pokazalo se da hranjenje glodavaca korijenjem hrasta starosti do pet godina posljedično znači gubitak do 77% volumena korijena, 96% korijenovih vrhova te smanjenje duljine korijena i do 97%, čime je potvrđeno da je preživljavanje oštećenih biljaka posve onemogućeno. Hranjenje glodavaca korom stabljike za posljedicu je imalo stvaranje grizotina površine od 16, 5 mm2 do 766, 5 mm2 i to prosječno na 1, 6, a najviše na pet mjesta na stabljici. Utvrđeno je da su štete na korijenu i stabljici rasle sa starošću biljaka. Usporedbom prosječnih vrijednosti volumena, duljine i broja vrhova korijena oštećenih i neoštećenih biljaka, ustanovljeno je da su razlike među njima statistički značajne kod gotovo svih visinskih kategorija biljaka i debljinskih kategorija korijena za koje je provedena usporedba. Ovim je istraživanjem dobiven kvalitativni nalaz šteta od glodavaca na korijenu hrastova pomlatka te je potvrđeno da je sustavno praćenje dinamike, ali i udjela podporodica u strukturi populacija sitnih glodavaca, zajedno sa evidentiranjem stanišnih prilika i prouzročenih šteta, preduvjet ekološki i ekonomski odgovornoj zaštiti šuma.

Urban forests provide numerous benefits which are expressed through ecological and social functions of forests, the most important of which is the recreational function. In order to fulfil those functions it is necessary to have safe and stable forest stands. Maksimir is the oldest and one of the largest urban forest in Zagreb with the total area of 139, 5 ha. On its entire surface there are many tracks used for recreation (walking, walking with dogs, jogging, encounters with people etc.)This work presents the management of Maksimir urban forest through the results of tree risk assessment along main walking tracks. The aim of tree risk assessment is to identify hazardous trees and to suggest arboricultural treatment in order to support healthy trees which will ensure sustainable management of forests. Safety area was defined along walking tracks, and tree risk assessment was done for three main walking tracks, where every tree in the area was examined and only hazardous were registered. The results of tree risk assessment gave grounds for defining tree care measures. The results of research revealed that the main reason for marking a tree as hazardous was a dead tree crown. Most of such trees were in the lower diameter classes, suppressed and overcome by neighbour dominant trees, and should be removed before they become a threat for visitors. Tree risk assessment also includes identification of growth defect symptoms and frequency of mechanical wounds. It was observed that most of the wounds and defects were on the butt end and stem of trees. Protection of those parts of trees is particularly important as most of the trees are in the age of physiological maturity and their site conditions have been altered, which limits them to further dieback. The prescribed tree care intervention for hazardous trees in almost half of the cases was felling, which was mainly associated with dead tree crowns, while a smaller number of trees had mechanical wounds that made them hazardous. Other assigned tree care interventions included pruning of the crown (mainly dead wood pruning overlooking tracks) and further monitoring (with additional inspection). Tree risk assessment revealed the main reason for which trees were rated as hazardous and indicated the need to carry out regular tree care interventions.

U radu se prikazuju rezultati rasadničkog pokusa u kojemu se ispituje utjecaj preparata za folijarnu primjenu Hungavit na kvalitetu sadnica obične bukve i hrasta lužnjaka golog korijena. Pokusi su postavljeni kao randomizirani blok s tri tretmana i tri ponavljanja. Utvrđen je pozitivan utjecaj Hungavita na uspijevanje sadnica. Kod bukve, najveći je utjecaj Hungavit imao na povećanje koncentracija kalija, kalcija i magnezija u lišću, biomasu lišća i stabljika, te porast broja vrhova korijena. Optimalna koncentracija za proizvodnju sadnica bukve je 2%. Kod hrasta lužnjaka utjecaj Hungavita je nešto manje izražen, u smislu da je optimalna koncentracija 1%, a Hungavit je djelovao pozitivno na koncentracije kalija, kalcija i magnezija u lišću te biomasu lišća i stabljika.

Common beech (Fagus sylvatica L.) is a dominant broadleaved tree species in Croatia. In the last three decades, silver fir (Abies alba Mill.) dieback of catastrophic proportions in Croatia, partly caused by climate change, has led to a major expansion of pure beech over former beech – fir sites. The area of beech – fir forets has been reduced and the proportion of pure beech forets has increased due to natural regeneration of beech in sun – exposed sites. Although beech is a species of wider ecological amplitude in comparison with fir, this contradicts recent forestry practices (regeneration under canopy shelter) and the defined ecological requirements of beech (sensitivity to sunburn, shade tolerance). Climate change is perhaps the most critical factor facing the current generation of land managers who are concerned about the future condition of natural and managed ecosystems. The results of two seperate experiments, a nursery experiment and a case study, will be discused in the light of the ecophysiological status of beech in changed stand and climate conditions. The influence of climate and relief properties on the crown conditions of beech on Medvednica massif was monitored in the period 2004 – 2006. Climate and relief properties were found to significantly influence the crown conditon of beech trees. To determine the ecophysiological response of beech seedlings to full sunlight conditions, a nursery experiment was established with three fertilization treatments (2, 4 and 6 g of Osmocote Exact per 1 liter of substrate) to simulate various soil fertility conditions (poor, adequate and excessive availability of nutrients) in Hajderovac nursery. Height, diameter and biomass of seedlings increased with fertilizer dose. Concentrations of N, P and K increased with fertilizer dose, while Ca and Mg concentrations showed negative effects of overfertilization at the highest fertilizer dose. Root length, surface area and number of root tips were highest in the intermediate treatment while roots were least developed at the highest fertilizer dose. Assimilation rates of seedlings corresponded well with leaf mass (r2=0, 59), leaf (r2=0, 44) and root total nitrogen (r2=0, 58) and total leaf phosphorus (r2=0, 45).

Sušenje obične jele (Abies alba Mill.) većih razmjera, prisutno u Hrvatskoj u zadnjih dvadesetak godina, dovelo je do netipičnih stanišnih uvjeta za rast podmlatka obične bukve (Fagus sylvatica L.) na područjima bukovo- jelovih šuma. Ovakav razvoj događaja u kontradikciji je s prihvaćenom šumarskom praksom i poznatim ekološkim zahtjevima bukve (skiofilnost, osjetljivost na sušu). Da bismo odredili osnovne parametre ekofiziološkog odziva klijanaca bukve na uvjete punog osvjetljenja, postavljen je rasadnički pokus s tri razine gnojidbe (2, 4 i 6 g Osmocote Exact kompleksnog mineralnog gnojiva po litri uzgojnog supstrata), s ciljem oponašanja različitih uvjeta plodnosti tla (niska, optimalna i visoka dostupnost hraniva). Za svako tretiranje utvrđena je ukupna biomasa klijanaca (lišće, stabljika, korijen) a biljni materijal analiziran je na sadržaj biogenih elemenata (dušika, fosfora, kalija, kalcija i magnezija). Izmjerena je visina i promjer korijenovog vrata biljaka, a morfologija korijena analizirana je pomoću WinRhizo softverskog paketa. Za mjerenja fotosintetskog kapaciteta, krivulje svjetlosnog zasićenja (0, 50, 250, 600 i 1200 μmol/m2s) i A-Ci krivulje (0, 100, 400, 700 i 1000 μmol CO2/l) dobivene su pomoću Li- Cor LI-6400 u kontroliranom okruženju. Visina, promjer i biomasa sadnica povećavala se s dozom gnojiva. Koncentracije N, P i K rasle su s dozom gnojiva, dok su koncentracije Ca i Mg pokazivale negativni učinak prekomjerne gnojidbe pri najvišoj dozi gnojiva. Duljina korijena, površina korijena i broj vrhova bili su najveći u srednjem tretiranju, a korijen se najslabije razvijao pri najvećoj dozi gnojidbe. U svim tretiranjima asimilacijska sposobnost bila je povezana s masom lišća (r2=0, 59), koncentracijom N u lišću (r2=0, 44) i korijenu (r2=0, 58) kao i koncentracijom P u lišću (r2=0, 45).

Silver fir dieback of catastrophic proportions, present in Croatia in the past three decades has led to major spread of pure beech on beech-fir sites. The area of beech-fir forests has been reduced and proportion of pure beech forests has increased (Croatian Forests Ltd., Forest management plan 2007), due to natural regeneration of beech on sun-exposed sites. This is in contradiction with recent forestry practices (regeneration under canopy shelter) and known ecological requirements of beech (Fagus sylvatica L.) (sensitivity to sunburn, shade tolerance). To determine the ecophysiological response of beech seedlings to full sunlight conditions, a nursery experiment was established with three fertilization treatments (2, 4 and 6g of Osmocote Exact per 1 liter of substrate) to simulate various soil fertility conditions (poor, adequate and excessive availability of nutrients, simulating nutritionally poor, moderately rich and very rich soils). For every treatment total biomass of seedlings (foliage, stem, roots) has been determined and plant material chemically analysed. Height and root-collar diameter have been measured and roots morphologically analyzed (WinRhizo). Light saturation curves and A-Ci curves have been measured (LI-6400) in controlled environment . Height, diameter and biomass of seedlings increased with fertilizer dose. Concentrations of N, P and K were growing with fertilizer dose, while Ca and Mg concentrations showed negative effects of overfertilization at the highest fertilizer dose. Root length, surface area and number of root tips were highest in the intermediate treatment while roots were least developed at the highest fertilizer dose. In all cases assimilation rates of seedlings corresponded well with leaf mass (r2=0, 59), leaf (r2=0, 44) and root total nitrogen (r2=0, 58) and total leaf phosphorus (r2=0, 45).

Crna joha (Alnus glutinosa) raste u okolici Đurđevca u Podravini u čistim i mješovitim sastojinama na približno 2000 ha i važna je gospodarska vrsta drveća. Podravske sastojine nadaleko su poznate po bujnom uzrastu, visokovrijednom drvu, a s fitocenološkoga stajališta po prirodnom, raznovrsnom i bogatom sastavu. U svojoj disertaciji Glavač je (1960) detaljno istražio i opisao dvije asocijacije u kojima prevladava crna joha: na staništima koja su poplavljena stajaćom vodom utvrđena je fitocenoza crne johe s dugoklasim šašem (Carici elongatae-Alnetum glutinosae), a na nju se sukcesivno nadovezuje mnogo suša zajednica crne johe i poljskoga jasena sa sremzom (Pruno-Fraxinetum). Obje su asocijacije bile prije toga istražene i opisane u Europi. Glavač je fitocenoze prikazao u sintetskim tablicama s 28 snimaka, utvrdio je njihov florni sastav, sistematsku pripadnost, sindinamiku, raščlanjenost i ostale značajke. Od Glavačevih istraživanja u proteklih pedesetak godina izgrađene su hidrocentrale na rijeci Dravi, promijenjeni ostali ekološki uvjeti i obnovljena većina crnojohovih šuma. To nas je ponukalo da recentnim fitocenološkim istraživanjima pokušamo utvrditi posljedice promjena na građu, dinamiku i strukturu sastojina u dvjema spomenutim asocijacijama. Na temelju 26 fitocenoloških snimaka i ostalih relevantnih podataka općenito smo utvrdili promjene u flornom sastavu u smjeru nestajanja hidrofita i higrofita i proširenju vrsta suših staništa, sukladno tomu znatnu promjenu odnosa površina istraživanih zajednica, njihova sindinamskoga razvoja i raščlanjenosti. U članku se govori i o problematici i potrebama detaljne fitocenološke razrade ostalih crnojohovih šuma u Hrvatskoj koje su istraživane relativno ekstenzivno i opisane u četiri asocijacije. U tom smislu obrazlaže se potreba šire analize i nastavka istraživanja.

Požeško gorje odlikuje se raznolikim sinekološkim uvjetima što je uvjetovalo pridolazak različitih bukovih šuma na relativno malenome prostoru. U radu su ustanovljene i opisane tri bukove asocijacije. Analizom fitocenoloških snimaka asocijacija Luzulo-Fagetum svrstana je u srednjoeuropsku acidofilnu svezu Luzulo-Fagion, dok su asocijacije Vicio oroboidi-Fagetum i Festuco drymeiae-Fagetum svrstane u ilirsku svezu neutrofilnih bukovih šuma brdskoga pojasa (Aremonio-Fagion). To je potvrdila i usporedba bukovih zajednica na požeškome gorju kombiniranjem odnosa flornih geoelemenata i bioloških oblika biljaka sa posebnim osvrtom na ilirske, ilirikoidne i vrste reda Quercetalia pubescentis.