Iako se šumarstvo smatra tradicionalnom strukom i područjem znanosti, njegova važnost i značenje u današnjim prilikama povećane svijesti o klimatskim promjena i dobrobiti održivog razvoja prirodnih ...ekosustava svakim danom sve više raste. Suvremeni i ažurirani studijski programi neophodni su uvjet za primjereno obrazovanje stručnjaka za gospodarenje šumskim ekosustavima i proizvodima.
Bolji uvid u studentsku socioekonomsku pozadinu i motivaciju za studij mogu poslužiti za unapređenje studijskih programa, kao i pomoć studentima u postizanju boljih rezultata. Provedeno je istraživanje radi usporedbe trajanja preddiplomskog studija i postignute prosječne ocjene s analizom čimbenika koji bi mogli na to utjecati. Proveden je upitnik među studentima (N=185) diplomskih studija Šumarskog fakulteta Sveučilišta u Zagrebu akademske godine 2016/2017. Analizom varijance testirane su razlike između prosječnih ocjena studija i trajanja studija. Za procjenu utjecaja čimbenika na trajanje studija provedena je višestruka linearna regresija.
Približno trećina studenata dolazi iz Zagreba. Više od dvije trećine studenata na šumarskom odsjeku je završilo gimnaziju, dok su na drvnotehnološkom odsjeku dvije trećine studenata završile srednje strukovne škole. Prosječne ocjene i trajanje studija ne razlikuju se statistički značajno po studijskim programima ni po spolu. Prosječna ocjena studija i trajanje studija statistički su značajno negativno korelirani za sva tri studijska programa. Statistički značajni prediktor trajanja studija za sva tri studijska programa je prosječna ocjena studija. Za studij Šumarstvo dodatni prediktori za kraće studiranje su stipendija i osobna motivacija, dok su za studij drvne tehnologije spol (M), stipendija i završena srednja škola (gimnazija).
Although forestry is often considered as a traditional field of applied science, it resumes its importance in context of increased awareness of climate change and benefits coming from natural ecosystems. Updated and contemporary study programmes are needed to ensure an adequate education on managing forest ecosystems and its products.
A better insight in student background and their motivation for studies are welcome to improve the study programmes and also to find the ways how to help students achieve better results. A case study research was carried out to measure success of studies by duration of studies and average grades achieved, with possible causes. Three undergraduate study programmes on Zagreb Faculty of Forestry were analyzed (Forestry N=94, Urban forestry N=54 and Wood Technology N=39), with data acquired from a questionnaire among forestry graduate students on the same faculty academic year 2016/2017. A Factorial ANOVA was performed to test differences between the studies, and a multivariate linear regression for the influence of predictor variables on the duration of study.
Although this profession is associated with people from rural areas, about one third of all students comes from the capital city (Figure 1). Students of Wood Technology (DT) are mostly coming from vocational schools (70%) while Forestry (ŠO) and Urban Forestry (UŠ) students are mostly from gymnasiums (67% and 83%). For about 91% of students main motivation was a personal sake rather than a family interest (9%). Average scores and the duration of study on three study programmes have not been proven significantly different between the studies, nor between male and female students (Table 5). A longer time of study is proven to negatively correlated with the average grades on all study programmes: ŠO (r = -0,56), UŠ (r = -0,55) and DT (r = -0,38) (Table 4.). Statistically significant predictor for duration (with logarithmic transformation) on all study programmes in regression analysis was the average grade, with negative sign, thus leading to a shorter study time. Additional statistically significant predictors for ŠO were obtained grant and personal motivation (negative sign), and for DT were sex, obtained grant, and type of high school (Table 6).
In recent decades, the golden jackal
Canis aureus
has experienced a population increase in many European countries, including Croatia. As a result, human-jackal conflicts (e.g., damage to livestock ...and wildlife, general nuisance in (sub)urban areas) have increased dramatically, and there is an urgent need to develop and use a range of mitigation tools that also aim to control population growth. Hunting is one of the well-known tools for population control; therefore, the aim of this study was to determine the effects of habitat type and weather conditions on jackal hunting success. From 2019 to 2023, a total of 217 jackals were culled during 106 hunting events in an approximately 10,500 ha lowland habitat along the Sava River in central Croatia. All jackals (56% males and 44% females) were culled using small calibre rifle (222 Remington) with night vision scope. Based on age structure, 16% juveniles and 84% adults were shot, and the average catch per unit effort (CPUE) was 2.0 animals/day. The best hunting success was obtained by attracting jackals with a calling method, i.e., by playing the sound of a wounded hare. Regarding the type of habitat, 56% of the culls were in cultivated, non-forested areas. It was confirmed that weather conditions, i.e., daily temperature and precipitation, influence hunting success, especially for males. Hunting success of adult males was lower on days with higher temperatures and on days with more precipitation. We can state that individual hunting with using calling method is an effective tool for successful golden jackals harvesting; moreover, jackal hunting can minimize the conflict with gamekeepers and farmers and would help to improve public perception of jackals.
•Flowering period, compatibility relations and fruit set of sweet cherry were assessed.•Full bloom synchronization was related to better pollen growth throughout pistil.•Pollen arrested growth in the ...middle part of pistil following self-pollination.•Pollen-pistil interactions determine the final fruit set.•Compatible pollinizers for each cultivar are recommended.
Pollination success and final fruit set of sweet cherry depends on self- and cross- (in)compatibility relations among cultivars in orchard. The objective of this study was to determine the compatibility relationships and to select pollenizers for the most important Croatian sweet cherry cultivars, ‘Gomilička’ and ‘Stonska’. Phenological observations, pollen germination, pollen tube growth and fruit set were assessed following self- and cross-pollination treatments in two flowering seasons. In general, we found overlap of flowering periods of all cultivars included in the study, but low synchronization was observed for the full-bloom period among traditional cultivars, particularly ‘Stonska’ (early cultivar) and ‘Tugarka’ (late cultivar). There was a significant difference in fruit set among the type of pollinations and pollen donors. ‘Gomilička’ and ‘Stonska’ are self-incompatible, and cross-pollination is necessary for good fruit set. According to the overlap in flowering time and fertilization level in ‘Gomilička’, cross-pollination with ‘Garnet’, ‘Isabella’ and ‘Starking Hardy Giant’ was more effective than that of the traditionally grown cultivars ‘Stonska’ and ‘Tugarka’, and introduction of these cultivars as pollenizers is a good choice that can provide regular and abundant fruit set. Despite the different S-allele combinations of traditional cultivars, overlap in flowering time with some of the introduced cultivars, and favourable climatic conditions, we found also significant effects of pollen-pistil interactions in the style and ovary on the dynamics of pollen tube growth and final fruit set. Inter-incompatibility reactions between cultivars were not observed.
For the purpose of forest management planning in Croatia, forest inventory is performed on sample plots of permanent sizes, generally from 500 to 1,000 m². Such plots have been accepted in practice ...on the basis of experience. Thus, the plot size has only partially been adjusted to different forest types. Although methods of sample selection are regulated by Forest Management Regulations and are limited to plots of permanent sizes, the Regulations still allow plot sizes to be adjusted to specific stand conditions. This article compares the results of forest measurement on differently sized plots in order to estimate their efficiency in selection fir and beech stands. Research was carried out in Gorski Kotar, where the stand structure was recorded using a sample of experimental plots. Systematic sampling with a random start was used to establish 103 sample plots in the management units of »Delnice« and »RavnaGora«. Breast height diameters over 10 cm and tree heightsweremeasured on circular plots of 20mradius, set up across a 100 x 100 m square grid, and their positions in the space (azimuth and distance from the centre) were recorded. The values of structural elements (number of trees, basal area and volume) were calculated from the obtained data bymeans of a specially constructed computer programme CirCon for the plots and stands. The precision of estimates was expressed as a relative sample error with 95% confidence. Thanks to spatial data for all the trees, a calculation was made of the structure for sample plots in the radius range from 4 to 20 m. The precision of structural elements estimate (sample error) was calculated for each plot size. The average values in differently sized plots were compared with repeated measurement analysis of variance (RM ANOVA) with significance level of 0.05. The results of different plot sizes were subsequently tested by means of the Fisher’s LSD 'post hoc' test. On a sub-sample of 24 standpoints, the time needed for field measurements on differently sized plots was later measured in order to estimate the efficiency of differently sized plots. From these data measurement time (t) for all plot sizes was assessed in dependence on plot area (P) using the equation t=a*PČb. Walking time and distance between the plots were measured, from which the travel speed in the field was calculated. The efficiency of plots of a particular size was evaluated by the precision of estimate and the time needed for measurements. The achieved efficiency index was evaluated as the product of squared sample error and total time expressed in relation to the efficiency of 20mradius plots. The efficiency for differently sized plotswas also assessed by means of the expected accuracy at given sampling intensity of 5% area (5% cruise), as set down in the Forest Management Regulations. The results show the differences in the estimate of structural elements in dependence on plot sizes, especially for tree number. The differences were confirmed as statistically significant (RMANOVA: F = 2.31, df = 102, p < 0.0001). Subsequent testing revealed that on the plots with radii less than 7 m the estimate of tree number was statistically significantly lower than in the larger plots. Asimilar trend did not prove to be statistically significant either for the basal area (ANOVA PM: F = 0.72, df = 102, p =0.8772) or for the volume (ANOVA PM: F = 0.78 df = 102, p = 0.8124). Expectedly a more precise estimate was obtained with an increase in plot size. Considerable improvement in the precision was observed up to plot radii of about 13 m. The trend was slowed down with further increase: consequently, in terms of precision, plots with at least the above radii are recommended. The assessment accuracy of tree numbers in the smallest plots was better by 10% than that of the basal area; however, this difference decreases as the plot size increases, to become equal at plots with radii of about 12 m. The difference in the assessment accuracy of the basal area and volume ranges from about 2%in the smallest plots to less than 1%in the largest plots with 20m radius. In the case of smaller plots, apart from poorer precision of estimates, there were also bigger deviations from the average obtained on larger plots. With regard to the average assessment value of tree number, the basal area and volume, plots with radii greater than 10 m would be acceptable in the study area. The average measurement time increases almost linearly with an increase in plot size. In terms of the achieved efficiency index at the same number of plots, the smallest plots proved to be the least efficient, while the efficiency increases considerably up to 9 m radius, and levels from radii larger than 13 m. Along with the number of plots adjusted to the given sample size intensity of 5%, plots with radii between 8 and 15 m proved to be more precise than smaller and bigger plots. Time expenditure uniformly decreases with the application of a smaller number of bigger plots in relation to a larger number of smaller plots with an equal total area. Hence, the use of bigger plots is more practical since differences in precision are negligible. In terms of the number of measured trees per plot as a practical criterion that affects the quality of the results and of field work, plots with radii between 12mand 15mare recommended, which contain between 20 and 30 trees on average. This research confirmed the assumption that the reliability of estimates depends on plot size. Specific numerical relationships were obtained for the investigated selection stands. Plots of 500 m2, common in forest management practice, proved to be adequate for the investigated stands. Nevertheless, larger plots could significantly contribute to better precision of estimates at identical sample size. In terms of efficiency, these plots are definitely acceptable, taking into account the fact that even larger plots could also be efficient at identical sample size. By adjusting the size and number of plots to the prescribed intensity, standard plot sizes proved to be adequate. Still, plots of larger radii would possibly save the measurement time. Additional research involving a larger sample and broader range of stand conditions would give a clearer insight into the effect of plot size on precision of estimates. It would also enable better adjustment of plot sizes to individual stands for the purpose of forest inventory rationalization. For similar beech-fir selection stands, a comparison of nested plots (concentric circles) that are adjusted to the diameter structure should definitely be made. By doing so, the efficiency of assessment reliability and measurement efficiency could be improved, which is neglected by the present regulations.
Purpose
Simultaneous analyses of the contents and ratios of 12 cytokines and growth factors in single samples of human tears were performed, and the results were compared between a group of healthy ...subjects and a group of patients with Graves’ hyperthyreosis (GH) without thyroid-associated orbitopathy (TAO).
Methods
Determinations and concentration measurements of interleukins (IL-2, IL4, IL-6, IL-8, IL-10, IL-1α, and IL-1β) interferon (IFN-γ), tumor necrosis factor (TNF-α), monocyte chemoattractant protein (MCP-1), vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF) were performed with single tear samples from 21 patients with hyperthyreosis and 22 healthy subjects. The analyses were performed using a Randox microchip with an Evidence Biochip Array Analyzer.
Results
We found significant differences between the healthy donor group and the hyperthyreosis group in the levels of IL-6, IL-10, VEGF, IL-1α, and MCP-1. The concentration of IL-6 was considerably higher in the hyperthyreosis group, IL-10 was higher in the healthy donor group, and VEGF and MPC-1 were higher in the hyperthyreosis group. The IL-8 and IFN-γ levels were higher in the hyperthyreosis group. The ratios of all of the cytokines to anti-inflammatory IL-10 were significantly elevated in the hyperthyreosis group.
Conclusion
There are clear differences in the levels of cytokines and growth factors in the tears of healthy subjects and patients with GH without TAO. Tear cytokine changes and related dysfunctional tear syndrome (DTS) could be an early sign of occult TAO in Graves’ hyperthyreosis patients.
Purpose: Clinical experience regarding the fluctuations of the refractive error of the eye during the different stages of Graves' ophthalmopathy observed through outpatient clinic frequent check-ups ...points towards an underestimated and often overlooked problem. Published data about it are sparse. The clinical manifestations of Graves' ophthalmopathy can be understood from the perspective of "compartment syndrome" and literature implies how such changes can affect the refractive error and consequently, the visual acuity. The purpose of the study was to explore how the clinical activity score of Graves' ophthalmopathy affects refractive error and visual acuity. Patients and Methods: The study was prospective and observational, including 60 eyes of 30 patients with clinically active Graves' ophthalmopathy. All the patients were monitored and evaluated over a period of 36 months by the clinical activity score, spherical equivalent and visual acuity. All the observed parameters were statistically analyzed. Results: The mean values of spherical equivalent and visual acuity throughout the observed period showed continuous fluctuation. Repeated measure analysis of variance showed statistically significant differences in visual acuity and spherical equivalent over the observed period. There was a statistically significant positive correlation between visual acuity and clinical activity score. The correlation between spherical equivalent and clinical activity score was also positive but not statistically significant. Conclusion: A decrease in the clinical activity score is either the result of a spontaneously resolving course of Graves' ophthalmopathy or a consequence of treatment, so lowering in fluctuation of refractive error and improved visual acuity may be associated with a reduction in orbital inflammation. Keywords: Graves' ophthalmopathy, clinical activity score, refractive error, spherical equivalent, visual acuity
Silver fir is one of the most threatened conifer species in Croatia, especially at the western edge of its spread in Croatian Dinarides, where the decline in fir trees has resulted in significant ...ecological and economic issues. The aim of this study was to determine, over an 18-year monitoring period, the relationships of silver fir crown defoliation with climatic factors and structural attributes. We further analyzed the tree retention time in a given defoliation class and transition dynamics between defoliation classes, as well as the survival/mortality of trees. Data on silver fir defoliation were analyzed in two different forest types: in pure silver fir and in mixed silver fir and common beech stands. The climatic factors, primarily vegetation period air temperature, potential evapotranspiration, and dry season water deficit, were correlated with crown defoliation. Regarding the structural attributes, in the mixed stand with predominantly smaller trees, crown defoliation increased with reduced diameter at breast height, crown diameter, social class, and crown illumination. In the pure fir stand, crown defoliation increased with reduced crown diameter, greater crown asymmetry, greater crown illumination, and on trees with a stork’s nest crown. The retention time in defoliation classes differed for research sites. Transition dynamics were different only for trees in the highest defoliation class (dead trees). At the end of the study period, silver fir mortality was higher in the pure fir stand. Increased silver fir defoliation and mortality can be expected in the future, particularly in overmature stands under prolonged drought stress. Permanent forest monitoring could ensure the high-quality data needed for adaptive management of fir stands that could positively influence the structure of these stands and, thus, improve their health status.
Istraživanjem učinkovitosti suhih i mokrih Theysohn® naletno barijernih feromonskih klopki došlo se do novih spoznaja značajnih za monitoring populacija smrekovih potkornjaka –
Ips typographus
i
...Pityogenes chalcographus.
Tijekom 2014. godine 12 mokro-suhih parova crnih Theysohn® naletno barijernih feromonskih klopki postavljeno je u dvije g. j. UŠP Gospić na različitim nadmorskim visinama. Šest parova klopki postavljeno je u g.j. Žitnik na 500 metara nadmorske visine, a preostalih šest na nadmorskoj visini od 1100 metara u g.j. Štirovača u blizini nacionalnog parka Sjeverni Velebit. Između testiranih klopki nije utvrđena statistički značajna razlika broja ulovljenih potkornjaka, iako je suha feromonska klopka ulovila veći broj jedinki smrekovog pisara i šesterozubog smrekovog potkornjaka. Mokra i suha feromonska klopka pokazale su jednaku selektivnost prema predatorskoj entomofauni –
Thanasimus formicarius
i
Nemozoma elongatum.
U suhim feromonskim klopkama utvrđena je redukcija broja ulovljenih potkornjaka djelovanjem predatora. Kod vrste
T. formicarius
uočena je mogućnost bijega iz suhih feromonskih klopki. Rezultati provedenog istraživanja omogućuju racionalniji pristup monitoringu populacija smrekovih potkornjaka sustavom suhih i mokrih naletno barijernih Theysohn feromonskih klopki.
Efficiency of dry and wet flight barrier Theysohn® pheromone traps in catching the spruce bark beetles
Ips typographus
L. and
Pityogenes chalcographus
L.
Eight toothed spruce bark beetle (
Ips typographus
L.) and six toothed spruce bark beetle (
Pityogenes chalcogr
aphus L.) are most imported pests of mature spruce forests in whole Europe. When the populations are low they usually attack the trees which are weakened by snow, wind, highlight or some other biotic or abiotic factors. When the populations increase higher they can attack and kill living standing trees and-thus become primary pests. Monitoring of populations with pheromone traps is an important tool in integrated forests protection. During the last two decades the foresters in Croatia mainly use the classic black Theysohn® flight barrier pheromone traps for monitoring of spruce bark beetle populations in spruce forests.
The aim of the study was to investigate is there any significant difference in catches between dry and wet flight barrier pheromone traps, is there any possibility that bark beetles can escape from pheromone traps after they fall down in plastic box at the bottom of pheromone traps, and is there any difference in selectivity of compared traps to predator species (
Thanasimus formicarius
L.,
Nemozoma elongatum
L.).
In 2014. a field experiment was set up in spruce stands in two sites, one in higher elevation and one in lower elevation. In each site three black Theysohn® flight barrier pheromone traps using water in collecting box were compared with three traps with dry boxes, for each bark beetle species. The holes on the bottom of collecting boxes on wet traps were sealed with silicone. Also new made holes at the side of collecting boxes were covered with plastic net to stop the loss of captured bark beetles with water overflow. The traps were loaded with pheromone lures – Pheroprax® lure for
I
.
typographus
and Chalcoprax® for
P
.
chalcographus
.
Totally for each species were set up six pairs of dry-wet pheromone traps, three pairs on lower and three pairs on higher elevation.
The experiment started 17th of May and was finalized in the last week of September. The traps were emptied every eight days. The caught beetles were kept in 60% ethanol until the moment when they were determined and counted. Except the two main bark beetle species, also the predator species
T
. formicarius and
N
.
elongatum
were counted. In total 73.994 specimens of
I
.
typographus
were caught in dry, and 71.212 specimens in wet traps. In dry traps 214.950 specimens of
P
.
chalcographus
were caught, and 179.146 specimens in wet traps. There was no significant difference between dry and wet pheromone traps for both bark beetle species. It can be concluded easily that
I
.
typographus
and
P
.
chalcographus
could not escape from traps after they fall down in collecting box at the bottom of traps, what isn’t case with
Tomicus
species (Hrašovec & Pernek, unpublished results).
In both case bigger number of bark beetles (no statistically significant) were caught in dry traps. The reason may be the production of 1-hexanol and verbenon in wet traps. More dead bark beetles was found in wet pheromone traps what is logical because after they fall down in plastic hunting box which is full of water they get drown after some time, what is no case with bark beetles in dry pheromone traps. Increasing the number of dead beetles can reduce the efficiency of pheromone traps (Kretschmer, 1990; Bakke et al, 1983). The smell of dead bark beetles significantly reduce the efficiency of pheromone traps, but in the moment it wasn’t known which component were responsible for it. Lower efficiency of pheromone traps is consequence of production 1-hexanol and verbenon from dead bark beetles (Zhang et al., 2003).
Pernek (2006), Pernek & Lacković (2011) had a better monitoring results of silver fir bark beetle species (genus
Pityokteines
) with wet traps compared to dry traps. The classic black Theysohn® traps were used like in this experiment. The reason why the wet pheromone traps had shown a better results in previous research (Pernek, 2006; Pernek & Lacković, 2011) probably is consequence of different factors: biology and pheromone communication, swarming time, weather conditions and different type of stands. All this factor could have a important impact on pheromone trap catches.
There is no significant difference in selectivity of compared traps to predators. The dry pheromone traps catch less individuals of
T
.
formicarius
L. and more individuals of
N
.
elongatum
compared to wet traps. It had been observed the escape possibility of
T
.
formicarius
from dry traps. During the analysis of some samples just the eaten bark beetles had been found in dry traps, and there wasn’t any
Thanasimus
specimens.
N. elongatum
couldn’t escape from dry traps, and there was some reduction of caught six tooth bark beetles in dry pheromone traps by this predator.
The results support the use of both type of traps in monitoring of spruce bark beetle species. Although, dry trap setting in the field, collecting and analyzing of dry catches is much easier.
Biološki mehanizam listanja pod izravnim je utjecajem okolišnih čimbenika. Razvijeni su mnogi modeli i objavljene različite studije s ciljem što boljeg opisa pojedinog biološkog mehanizma fenoloških ...svojstava, a koji su izloženi upravo okolišnim čimbenicima tijekom svoga života. Temperatura je neminovno jedan od najbitnijih čimbenika za pokretanje mnogih procesa u biljci i upravo je ona okosnica većine izrađenih modela. Growing Degree Days model se temelji na minimalnim i maksimalnim temperaturama, te na baznoj temperaturi, odosno temperaturnom pragu iznad kojeg se aktiviraju procesi u biljci.
Istraživanja u ovome radu temelje se na desetogodišnjem monitoringu početka listanja hrasta lužnjaka u klonskoj sjemenskoj plantaži koja sadrži ukupno 53 genotipa. Cilj je bio utvrditi ponašanje svojstva listanja te implementirati dobivene rezultate u GDD model. S obzirom da je već poznato da hrast lužnjak ima svoje tri fenološke forme listanja (rane, intermedijarne i kasne), bilo je potrebno dokazati da se te tri grupe jasno diferenciraju i po temperaturnim sumama, odnosno GDD-u. Razdoblje monitoringa u svakoj godini bilo je oko 130/131 dan, odnosno od 1.siječnja do 10.svibnja. Izračunom GDD-a i povezivanjem tog modela s dobivenim vrijednostima početka listanja, iskazala se jasna segregacija na već spomenute tri forme. Svakoj fenološkoj grupi, dodijeljen je interval vrijednosti temperaturnih suma koje su potrebne da bi ta fenološka forma započela s listanjem. S obzirom na godišnje vrijednosti temperaturnih suma koje su potrebne pojedinoj formi da krene s listanjem, evidentno je bilo da vrijednosti značajno variraju kroz godine, i to za kompletno promatrano razdoblje. Upravo to variranje onemogućava da se putem GDD modela izradi simulacijski model, koji bi mogao, uz određena manja odstupanja, predvidjeti početak listanja za iduće razdoblje. Važnost predviđanja nije jednostrana, naprotiv, cijeli je niz sinergijskih čimbenika koji su izravno ili neizravno vezani za početak listanja pojedinih vrsta šumskog drveća, među kojima možemo spomenuti stadijni razvoj entomofagnih i fitopatogenih štetnika, koji su svojom biologijom usko vezani za biologiju određene vrste drveća.
S obzirom na izraženo variranje vrijednosti temperaturnih suma, po fenološkim formama, u istraživanja su uključeni i drugi okolišni čimbenici, kao što su količina oborina (mm), insolacija i broj dana. Cilj je bio ispitati kako se ova tri čimbenika ponašaju s obzirom na kretanje GDD vrijednosti, odnosno koji od ispitivanih čimbenika je preciznija poveznica za svojstvo početka listanja. Statističkom obradom podataka, jasno su i s visokim postotkom isključeni količina oborina i broj dana kao čimbenici koji definitivno ne utječu ili utječu s jako malim učešćem na kretanje vrijednosti GDD-a. Insolacija se iskazala kao čimbenik koji s najvećim udjelom sudjeluje u kretanju GDD vrijednosti i to za ranu fenološku formu sa 74,1 %, za intermedijarnu formu sa 90,6 %, te za fenološku formu kasnog listanja sa 78,7 %.
For ten years, 53 genotypes of Pedunculate Oak were monitored in a clonal seed orchard. The aim of the study was to clarify effects of forcing and chilling temperature as background of leaf unfolding of pedunculate oak through the different kind of prediction models. The Pedunculate Oak is known to have three phenoforms of flushing phases, i.e., early, intermediate and late, and substantially different Growing Degree Days (GDD) requirements were found among these phenological groups. For each of the phenological groups, the GDD interval value required for leaf unfolding was determined, but the values varied between years, rendering the development of a simulation GDD model difficult. For these reasons, other variables – day of year, precipitation and insolation – were included in the assessment. The aim was to examine how these environmental factors determine the GDD requirement for leaf unfolding in the three Pedunculate Oak phenological groups. The results suggest that for all three flushing groups, insolation and the day of year are statistically significant predictors for GDD. Insolation was demonstrated to be the primary factor with the largest influence on the GDD values. In the early flushing group, insolation accounted for 74.1 % of the variation, 90.6 % in the intermediate group, and 78.7 % in the late group. We recommend using the univariate GDD model for the early and intermediate flushing groups (GDDearly = −27.651 + 0.539 * insolation; GDDinter = −48.084 + 0.690 * insolation) and the multivariate model for the late flushing group (GDDlate = −237.839 + 0.559 * insolation + 2.479 * day of year). To break the dormancy, chilling is required to be in the range of ± 40 chilling units, and if the values are higher or lower, the trees require significantly higher forcing temperatures.
PDF
