The quantity and quality of seedlings in the nursery has an impact on the success of re-establishment and later growth. High germination rates enable a sufficient number of seedlings, and their ...quality is assessed using a number of parameters, including seedling height and root collar diameter. These parameters are influenced in some species by seed size, but the correlation between them is species-specific. The model species in this research was sweet chestnut (Castaneasativa Mill.), and seeds from 12 populations from two distinct biogeographical regions of Croatia were collected. We examined the influence of seed size on four parameters: germination rate, seedling height, root collar diameter and sturdiness quotient. Seed size has been shown to have a positive influence on both seedling height and root collar diameter, whereas no such correlation was noted for germination rate and sturdiness quotient. Significant differences in nut size and seedling growth parameters were found between the Mediterranean and continental populations, with higher values observed in the coastal Mediterranean populations. We concluded that seed origin and seed size have a significant impact on seedling growth and are important factors to consider when choosing seed material. Further nursery operations should consider seed origin and local environmental conditions when choosing seedlings for reforestation efforts and general forest operations.
When natural regeneration of Quercus robur stands is hampered by an insufficient acorn yield, human assisted sowing of acorns collected in non-affected stands and stored for some period of time is ...performed. To inhibit the development of fungi and acorn deterioration during storage, thermotherapy is usually applied by submerging acorns for 2.5 h in water heated to 41 °C. This research aimed to test the effect of four thermotherapy treatments of different durations and/or applied temperatures as well as short-term storage at −1 °C or 3 °C on acorn internal mycobiota and germination. Fungal presence in cotyledons was analyzed in 450 acorns by isolation of mycelia on artificial media, followed by a DNA-based identification. Germination of 2000 acorns was monitored in an open field trial. Thermotherapy significantly decreased fungal diversity, while storage at 3 °C increased the isolation frequency of several fungi, mainly Penicillium spp. The most frequently isolated fungi did not show a negative impact on acorn germination after short-term storage. The study confirmed the efficiency of thermotherapy in the eradication of a part of acorn internal mycobiota, but also its effect on the proliferation of fast-colonizing fungi during storage. However, the latter showed to be more stimulated by storage conditions, specifically by storage at 3 °C.
U članku se govori o značaju ukrasnih japanskih javora u projektima krajobraznog uređenja prostora i njihovoj velikoj varijabilnosti. Detaljno je objašnjena metoda proizvodnje podloga iz sjemena i ...tehnika bočnog cijepljenja koja se provodi u zaštićenim prostorima krajem zime. Objašnjeni su svi čimbenici koje treba uzeti u obzir prije, za vrijeme i nakon cijepljenja. U članku su pojašnjene oznake koje se koriste u rasadničkoj proizvodnji cijepova, a preuzete se iz standarda europske udruge rasadničara - European Nurserystock Association (E.N.A.). Ovaj stručni rad može poslužiti svim rasadničarima, ali i pojedincima koji si sami žele razmnožiti određeni kultivar japanskog javora.
The article discusses the importance of decorative Japanese maples in landscaping projects and their great variability. The method of production of seed rootstocks and the side-veneer technique of grafting, which is carried out in protected areas in late winter, are explained in detail. All factors to be considered before, during and after grafting are explained. The article clarifies the codes used in the nursery production of grafted plants and is taken from the standards of the European Nurserystock Association (E.N.A.). This professional paper can serve all nurseries as well as individuals who wish to propagate a particular cultivar of Japanese maples.
U članku se definira pojam šumskih voćkarica ili šumskoga voća koji je godinama prisutan u hrvatskom šumarstvu i navedeni pojam se uspoređuje s ostalim pojmovima koji nisu istoznačnice, a odnose se ...na šumsko drveće, grmlje i prizemno rašće jestivih i ljekovitih plodova, samonikle voćke i domesticirane voćke. Za svaki pojam navode se tipični predstavnici vrsta. Prikazana je proizvodnja po vrstama drveća u rasadnicima Hrvatskih šuma d.o.o. u 2019./2020. godini prema upravama šuma podružnicama (UŠP), organizacijskim jedinicama i rasadnicima. Što se tiče proizvodnje šumskih voćkarica, drveća jestivih i ljekovitih plodova, samoniklog voća i domesticiranih voćki ista je prisutna u samo tri rasadnika Hrvatskih šuma d.o.o. (Zelendvor, Oštarije i Lukavec). U navedena tri rasadnika ukupno se proizvodi (2019./2020.) svega četiri vrste iz navedene četiri kategorije: oskoruša, divlja trešnja, pitomi kesten i crni orah. Sve četiri vrste se proizvode u rasadniku Zelendvor, dok se u rasadniku Oštarije proizvode šumske sadnice oskoruše i divlje trešnje, a u rasadniku Lukavec samo šumske sadnice divlje trešnje. Prikazana je proizvodnja i isporuka sadnog materijala navedenih vrsta iz rasadnika Hrvatskih šuma d.o.o. za razdoblje od 2012. do 2017. godine. Na zalihama ili u proizvodnji, u svim rasadnicima Hrvatskih šuma d.o.o. za razdoblje od 2012. do 2018. godine najviše je bilo sadnica crnog oraha u iznosu od 183 670 komada, slijede sadnice divlje trešnje s 132 069 komada, pitomog kestena s 53 010 komada i divlje kruške s 4 882 komada. Najviše isporučenih sadnica, sukladno proizvodnji, bilo je kod crnog oraha i to u iznosu od 191 435 komada, slijede sadnice divlje trešnje s 71 954 komada, pitomog kestena s 28 515 komada i divlje kruške s 2 860 komada. U promatranom istraživanom razdoblju (2012.-2018.) u svim rasadnicima Hrvatskih šuma d.o.o. proizvodilo se samo 4 vrste iz navedenih kategorija, s ukupnom zalihom ili proizvodnjom od 373 631 komada šumskih sadnica i isporukom od 294 764 komada. Ukupno gledano za sve četiri vrste vidi se da je 78 867 komada sadnica više uzgojeno nego što je isporučeno. Zbog mogućnosti ekološkog uzgoja, dobre prilagodljivosti vrsta na globalne klimatske promjene, davanja državnih poticaja i ne previše zahtjevne njege, u bliskoj budućnosti bit će sve naglašeniji uzgoj vrsta za pridobivanje sekundarnih ili ne drvnih šumskih proizvoda u plantažama. Zbog promjene klimatskih uvjeta i sinergizma brojnih nepovoljnih biotskih i abiotskih čimbenika, mnoge autohtone vrste su danas ugrožene i postepeno se ili naglo suše i propadaju. Nekim će vrstama šumskih voćkarica, šumskog drveća, grmlja i prizemnog rašća jestivih i ljekovitih plodova, samoniklih voćki i domesticiranih voćki pogodovati promjena klime, što će dovesti do širenja njihovog prirodnog areala, uz povećanje potencijalnih površina pogodnih za umjetni uzgoj.
The article defines the term forest fruit trees or forest fruits that have been present in Croatian forestry for years and compares the term with other terms that are not synonymous and refer to forest trees, shrubs and ground growth of edible and medicinal fruits, wild fruits and domesticated fruits. Typical species representatives are listed for each term. The production by types of trees in the nurseries of Hrvatske šume d.o.o. is shown. in 2019/2020 years according to Forest Administration (FD), organizational units and nurseries. Regarding the production of forest fruit trees, edible and medicinal fruit trees, wild fruits and domesticated fruits, it is present in only three nurseries of Hrvatske šume d.o.o. (Zelendvor, Oštarije and Lukavec). In these three nurseries, a total of only four species from the above four categories are produced (2019/2020): service tree, wild cherry, sweet chestnut and black walnut. All four species are produced in the Zelendvor nursery, while in the Oštarije nursery, wild cherry seedlings are also produced, and in the Lukavec nursery only wild cherry seedlings are produced. The production and delivery of planting material of these species from the nursery of Hrvatske šume d.o.o. is shown. for the period 2012 to 2017. In stock or in production, in all nurseries of Hrvatske šume d.o.o. for the period from 2012 to 2018, there were mostly black walnut seedlings in the amount of 183,670 pieces, followed by seedlings of wild cherry with 132,069 pieces, sweet chestnut with 53,010 pieces and wild pear with 4,882 pieces. The most delivered seedlings, according to production, were black walnuts in the amount of 191,435 pieces, followed by wild cherry seedlings with 71,954 pieces, sweet chestnuts with 28,515 pieces and wild pears with 2,860 pieces. In the observed research period (2012-2018) in all nurseries of Hrvatske šume d.o.o. only 4 species from the above categories were produced with a total stock or production of 373,631 pieces of forest seedlings and a delivery of 294,764 pieces. In total, for all four species, it can be seen that 78,867 pieces of seedlings were grown more than delivered. Due to the possibility of organic farming, good adaptability of species to global climate change, providing incentives and not too demanding care, in the near future there will be increasing emphasis on species breeding to obtain secondary or non-timber forest products in plantations. Due to changing climatic conditions and the synergy of a number of unfavorable biotic and abiotic factors, many indigenous species are endangered today and are gradually or abruptly drying up and decaying. Some species of forest fruit trees, forest trees, shrubs and ground growth of edible and medicinal fruits, wild fruits and domesticated fruits will benefit from climate change, which will lead to the expansion of their natural range with increasing potential areas suitable for artificial cultivation.
To preserve the sustainability of Quercus robur forests, which is at risk due to the disturbed natural regeneration, human assisted sowing of acorns or planting of oak seedlings is often performed. ...However, the success of these methods depends greatly on the use of high-quality sowing and planting material. Thermotherapy is thus often employed to decrease the acorn mycobiota and maintain their quality during the storage. The aim of this study was to test the impact of acorn thermotherapy, followed by a short-term storage at −1 °C or 3 °C, on the quality of related oak seedlings, which was assessed based on the easily observable morphological characteristics. Height, root collar diameter and seedling form were measured or noted for the 1284 and 1190 seedlings at the age of four months and three years, respectively. It was found that acorn thermotherapy affirmatively affected seedling height, especially at the early growth stage. Positive impact on other seedling attributes could not be decisively confirmed because of the lack of the continuity of the effect (not visible in both younger and older seedlings) and the prevailing impact of other factors. Different acorn thermotherapy conditions (temperature and duration) and short-term storage temperatures appeared to be associated only with the occurrence of stem forking at the earlier stage of seedling growth.
There is a growing trend in the world of planting fast growing species (rotations 5 to 10 years). Their primary purpose is the production of wood fibers and biomass, but they certainly represent the ...potential in making solid wood products as well. One of the fast-growing species is Paulownia sp., a species of extremely fast growing wood. Plantation breeding of Paulownia sp. in Croatia is increasing, although there is a little knowledge about the technical properties of Paulownia wood and its end use is questionable. This paper presents preliminary results of some physical properties of juvenile wood of two Paulownia hybrids planted in the area near the town of Glina in the Republic of Croatia. One hybrid is 9501 ((Paulownia fortunei × Paulownia elongata) × (Paulownia fortunei × Paulownia tomentosa)) and the other hybrid is Shan Tong (Paulownia fortunei × Paulownia tomentosa). The aim of this study was to investigate physical properties of juvenile wood of two Paulownia hybrids from one site in Croatia, to determine differences in physical properties of wood between two hybrids and to evaluate the correlation between density and shrinkages of each hybrid. Significant differences in oven dry density, basic density and density at maximum MC, between the two hybrids were determined. There is no statistically significant difference in longitudinal, radial, tangential and volumetric shrinkages between the two hybrids.
U današnje je vrijeme zamjetan sve češći trend sadnje brzorastućih vrsta drveća (ophodnje od 5 do 10 godina). Te su vrste primarno namijenjene proizvodnji drvnih vlakana i biomase, ali svakako je vidljiv i njihov potencijal u proizvodima od cjelovitog drva. Jedna od brzorastućih vrsta je Paulownia sp., koju odlikuje izrazito brz rast. Iako se malo zna o tehničkim svojstvima drva paulovnije, a njegova je krajnja upotreba upitna, u Hrvatskoj je u porastu plantažni uzgoj paulovnije. U ovom su radu prikazani preliminarni rezultati istraživanja nekih fizičkih svojstava juvenilnog drva hibrida paulovnije s lokaliteta u blizini grada Gline u Hrvatskoj. Prvi je hibrid 9501 ((Paulownia fortunei × Paulownia elongata) × (Paulownia fortunei × Paulownia tomentosa)), a drugi Shan Tong (Paulownia fortunei × Paulownia tomentosa). Cilj rada bio je istražiti fizička svojstva juvenilnog drva hibrida paulovnije s lokaliteta u Hrvatskoj, utvrditi razlike u fizičkim svojstvima drva tih hibrida te odrediti međusobni odnos gustoće i utezanja unutar hibrida. Utvrđene su značajne razlike u gustoći drva u apsolutno suhom stanju, u nominalnoj gustoći i gustoći pri maksimalnom sadržaju vode između tih dvaju hibrida. Među hibridima nisu utvrđene statistički značajne razlike u longitudinalnome, radijalnome, tangentnome ni volumnom utezanju.
Background and Purpose: The study aims at comparing two (over 100 years old) floodplain oak-predominated forests in the Czech Republic (CZ) with two in of Croatia (HR) with regards to: i) their ...structure and yield and, more specifically, ii) individual oak tree characteristics including acorn production.
Materials and Methods: In both countries a different silvicultural concept is preferred (CZ: clear-cutting management with artificial regeneration, HR: shelterwood management with natural regeneration). The main research goal was to create a basic decision tool for forest managers and open some questions for future research.
Results: Despite the different natural and management practices, the total standing volume of floodplain forest was found to be similar in both countries, ranging from 500 to 700 m3·ha-1 (basal area: 34-41 m2·ha-1). In CZ generally more poor structure diversity was detected. Although in CZ the number of crop oaks (130-160 oaks per hectare) was almost double as compared with HR, the CZ oaks had shorter crowns, almost twice smaller crown projection, lower mean volume and lower share of valuable assortments.
Conclusions: Despite the total standing volume of oaks in HR being lower than in CZ, the total yield was observed in Croatia (loss in CZ ca. 22,000 €·ha-1). The acorn density and quality were generally higher in HR with a more even distribution as well. Despite more favourable climatic conditions in HR, the currently used management system in CZ floodplain forests should be gradually converted to the Croatian model with a multi-layered forest structure, more focused on individual tree growth and stability with high economical value and high reproductive potential.
Background and Purpose: The current study aims to evaluate the effect of the fruit size of service tree (Sorbus domestica L.) on physio-morphological properties of seeds and the seed germination ...process.
Materials and Methods: The fruit samples varying in size and divided on the basis of weight into small (5-10 g), medium (11-15 g) and large (16-20 g) were collected from the area of Vukomeričke gorice (45°34′45″N 16°00′11″E), Zagreb County, Croatia.
Results: In all fruits, a significant, positive and very high correlation was found between the fruit length and width (r=0.92). There was a negative and significant correlation between the fruit weight and the fruit shape index (r=-0.47). The number of filled seeds in fruit was significantly higher in large fruits (2.62 seeds) than in medium and small fruits (1.81 and 1.46, respectively). Seeds from large fruits had significantly greater length of radicle (3.89 mm) than those from medium and small fruits (3.27 and 2.88, respectively) after 120 days of stratification at 3°C. The mean germination time of seeds for all fruits in total was 107 days. The seeds with the highest weight had significantly lower rate of moisture absorption. After stratification the seeds of large fruits had the highest germination percentage (83.7%).
Conclusions: The findings obtained will likely impact the propagation of this plant species in the future, because the results of the study favour the usage of seeds obtained from large fruits since they showed highest germination rate.
Background and Purpose: Narrow-leaved ash (Fraxinus angustifolia Vahl) is one of the most important tree species of lowland floodplain forests in the Republic of Croatia. Recent significant climate ...changes, reflected in extreme temperatures and long dry periods, have had a direct impact on the dynamics and levels of groundwater, as well as on the dynamics of precipitation and floodwater, which are of decisive importance for the success of narrow-leaved ash. Our study aims to determine the morphological and physiological characteristics of seedlings of narrow-leaved ash after 72 days of drought, normal watering and substrate saturation.
Materials and Methods: The experiment was established in three treatments (drought, normal watering and saturation), and each treatment included two containers or 24 seedlings. A total of 72 seedlings were replanted. After 72 days, height growth and increment, water potential, photosynthetic efficiency and the total chlorophyll content in the leaf mesophyll were measured.
Results: Seedlings from the drought treatment wilted immediately. Seedlings saturated with water up to the root collar manifested better height and diameter growth, high water potential and a lesser physiological stress response as compared to the seedlings that were watered normally.
Conclusions: Seedlings of narrow-leaved ash, which is a hygrophytic tree species, do not tolerate dry conditions and no watering. Seedlings saturated with water for 72 days showed a better morphological-physiological status than the seedlings that received normal quantities of water.
U rod Paulownia, porodica Paulowniaceae, ubraja se od devet vrsta i nekoliko prirodnih hibrida koji od prirode rastu u Kini. Važne vrste u ovom rodu su: P. albiflora, P. australis, P. catalpifolia, ...P. elongata, P. fargesii, P. fortunei, P. kawakamii i P. tomentosa. U novije vrijeme hibridizacijom su dobiveni brojni hibridi s ciljem povećanja brzine rasta i prirasta te otpornosti na niske temperature. U Hrvatskoj se najčešće razmnožavaju hibridi paulovnije Shan Tong i 9501 iako postoje i drugi dobiveni vlastitim selekcijama. Cilj ovoga članka je objasniti načine razmnožavanja paulovnije u prirodi i problematiku njezine invazivnosti te razmnožavanje u rasadniku pomoću autovegetativne metode makropropagacije korjenovim reznicama. Postoje tri faze zakorjenjivanja reznica: inicijacija, indukcija i ekspresija. Postoji direktna i indirektna indukcija. Najosjetljiviji trenutak je povezivanje provodnih elemenata korjenčića i dijela stanice. Uspješnost pojave korjenčića na reznici ovisi o: fiziološkom stanju matične biljke, količini šećera, metabolizmu auxina, mineralnoj ishrani, metabolizmu fenola i dr. Postoje četiri faze razmnožavanja paulovnije iz korijenskih reznica: uzimanje i dorada korijenskih reznica s matične biljke u matičnjaku, pikiranje reznica u pvc lončiće ispunjene supstratom za zakorjenjivanje, zakorjenjivanje korjenskih reznica i osnivanje novog matičnjaka. Korijenske reznice paulovnije Shang Tong i 9501 uzimane su s obzirom na polaritet na način da se donji (distalni) dio korijena rezao pod kutom od 45 stupnjeva a gornji (proksimalni) pod kutom od 90 stupnjeva. Reznice su podijeljene su na kratke (8 cm) i dugačke (15 cm). Svaka skupina reznica dodatno je podijeljena na tanke i debele na način da razlika bude na oko vidljiva. Iz svake skupine u istraživanje je uzeto po 15 reznica. Napravljen je pokus na način da jedan dio reznica bude pikiran u grijanom stakleniku 7 dana od vađenja korijena a drugi dio nakon sušenja na sobnoj temperaturi u komori rasta. Prva skupina od 60 reznica uzeta je 14. prosinca i pikirana u perforirane pvc vrećice volumena 5,0 l i u gotovi supstrat za zakorjenjivanje Klasman Steckmedium. U supstrat za zakorijenjivanje dodano je 3g/l gnojiva s produženim djelovanjem treće generacije Osomocote Exact Standard 5-6M formulacije 15-9-12+2MgO+TE. Reznice nisu tretirane fitohormonom niti fungicidima protiv truleži. Pikiranje reznica je obavljeno na način da je gornja površina reza od 90 stupnjeva bila u razini supstrata. Duga skupina od 60 reznica stavljena je na sušenje u komoru rasta Kambič RK-980 CH. Temperatura u komori iznosila je 21 °C i relativna vlaga zraka od 40 % što predstavlja čuvanje reznica u konstantnim sobnim uvjetima. Reznice su čuvane u komori rasta 5 dana. Pikiranje je obavljeno na isti način kao i u slučaju prve skupine reznica 21.12.2017. godine. Prvo registriranje zakorjenjivanja obavljeno je 19.02.2018. godine što znači za prvu skupinu 67 dana od pikiranja a za drugu skupinu 60 dana od pikiranja. Sušenje reznica hibrida paulovnije Shan Tong dovelo do povećanja zakorjenjivanja u svim varijantama, a posebno je izraženo kod debelih reznica duljine 8 cm i debelih reznica duljine 15 cm. Može se preporučiti uzimanje debljih reznica i njihovo sušenje na sobnoj temperaturi u trajanju od 5 dana jer se dobiva značajnije veći postotak zakorjenjivanja. Pretjerana vlaga u supstratu za zakorjenjivanje korijenskim reznicama paulovnije negativno utječe na razvoj korijenskog sustava. Kod hibrida paulovnije 9501 također je utvrđeno kako sušenje reznica dovodi do povećanja zakorjenjivanja u svim varijantama, osim kod tankih reznica duljine 8 cm kod kojih je dobiven isti postotak zakorjenjivanja (33%). Posebno je zanimljiva situacija kod debelih reznica duljine 8 cm kod kojih se bez sušenja nije zakorjenila niti jedna reznica a sa sušenjem čak 80 %. Može se preporučiti uzimanje debljih reznica hibrida paulovnije 9501 i njihovo sušenje na sobnoj temperaturi u trajanju od 5 dana jer se dobiva značajnije veći postotak zakorjenjivanja. Postotak zakorjenjivanja reznica bez sušenja bio bi sigurno veći da su se uzele odmah nakon vađenja korijenskog sustava bagerom što se preporuča u praksi. U ovom slučaju minimalne temperature zraka od -4 °C i -5,6 °C dovele su do smrzavanja korijenskog sustava. Prosječna minimalna temperatura zraka u razdoblju od 8. do 14. prosinca. iznosila je svega 0,8 °C. Kod smrznutog korijena kora se odvaja rukom od drva a takve reznice ili propadaju ili tjeraju iz nižih adventivnih pupova. Korijenske reznice hibrida paulovnije Shan Tong i 9501 trebale bi se uzimati odmah nakon vađenja korijenskog sustava matične biljke a prosječne temperature zraka trebale bi biti iznad 0 °C. U ovim istraživanjima dokazana je štetnost temperatura od -4 °C i -5,6 °C na korijenske reznice jer su one dovele do njihovog smrzavanja. Najbolje kalendarsko vrijeme za vađenje korijenskih reznica, ovisno o godini, bilo bi u mjesecu ožujku. Utvrđena je mogućnost zakorjenjivanja korijenskih reznica hibrida paulovnije 9501 u običnoj vodi u kontroliranim uvjetima (bez svjetla, konstantna temperatura od 20 °C). Reznice su stavljene u „in vitro“ klijalicu Snijders Scientific B.V., ECD01E dana 21.12.2017. a fotografirane 21.02.2018. odnosno 62 dana od stavljanja u vodu.
The genus Paulownia, family Paulowniaceae, contains about nine species and several natural hybrids which are native to China. Some important species in this genus include P. albiflora, P. australis, P. catalpifolia, P. elongata, P. fargesii, P. fortunei, P. kawakamii and P. tomentosa. More recently, numerous hybrids have been obtained by hybridisation for the purpose of increasing the rate of growth and increment, as well as develop resistance to low temperatures. In Croatia, the most commonly propagated are the Paulownia hybrids Shan Tong and 9501, although there are also other hybrids obtained by selections in some “in vitro” laboratory. The goal of this article is to explore different propagation methods of Paulownia in the nature, the problem of its invasiveness and nursery propagation by means of autovegetative macropropagation method from root cuttings. There are three phases of rooting the cuttings: initiation, induction and expression. There is direct and indirect induction. The most sensitive moment is the connecting of the conductive elements of small roots with parts of a cell. The success of root development on the cutting depends on the physiological status of the parent plant, sugar quantity, auxin metabolism, mineral nutrition, phenol metabolism and others. There are four stages of Paulownia propagation from root cuttings: digging out and finishing of root cuttings from the parent stock, pricking out the cuttings into plastic containers filled with potting media, rooting the cuttings and the establishment of a new parent stocks. The Paulownia root cuttings Shang Tong and 9501 were taken with regard to the polarity in the following way; the bottom (distal) part of the root was cut at an angle of 45 degrees and the upper (proximal) part was cut at an angle of 90 degrees. The cuttings were divided into short (8 cm) and long (15 cm) cuttings. Each group of the cuttings was additionally divided into thin and thick cuttings, making the difference visible to the naked eye. A total of 15 cuttings were taken from each group for the purpose of our research. In the experiment, one part of the cuttings was pricked out in a heated greenhouse 7 days after root excavation and the other part of the cuttings was pricked out after drying at room temperature in the plant growth chamber. The first group of 60 cuttings was taken on December 14th and pricked out in perforated 5.0 l plastic bags filled with ready-made Klasman Steckmedium rooting medium. The rooting medium was enriched with 3g/l of Osmocote Exact Standard 5-6M formulation 15-9-12+2MgO+TE, the 3rd generation of controlled release fertilizers. The cuttings were not treated with a phytohormone or rot prevention fungicides. The cuttings were pricked out in such a way that the upper surface of the cut at 90 degrees was at the level of the potting medium. The second group of 60 cuttings was dried in the Kambić RK-980 CH growth chamber. The chamber temperature was 21 °C and the relative air humidity was 40%, which equalled storage of the cuttings under constant room conditions. The cuttings were kept in the growth chamber for 5 days. Pricking out was performed on December 12th, 2017 in the same way as the first group of cuttings. The first rooting registration was done on February 19th, 2018, which in the case of the first group means 67 days after pricking out and for the second group 60 days after pricking out. Drying the Paulownia Shang Tong hybrid cuttings increased the rooting success in all the variants, and was particularly evident in thick cuttings 8 cm long and thick cuttings 15 cm long. Selecting thicker cuttings and drying them at room temperature for 5 days can be recommended because this procedure yields a significantly higher rooting percentage. Excessive moisture in the potting medium used for the Paulownia root cuttings negatively affects root system development. It was also confirmed that drying the Paulownia hybrid 9501 cuttings increases the rooting success in all the variants, with the exception of thin cuttings 8 cm long, where the rooting percentage was the same (33 %). Thick cuttings 8 cm long present a particularly interesting case, where not one single cutting which was not dried took root, while as many as 80 % of cuttings took root after being dried. Taking thicker cuttings of the Paulownia 9501 hybrid and drying them at room temperature for 5 days can be recommended, because this procedure yields a significantly higher rooting percentage. The rooting percentage of cuttings without drying would certainly be higher if the cuttings had been taken immediately after the root system was dug out with a dredge, as recommended in practice. In this case, the minima
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