Pecan (Carya illinoinensis/Wangenh./K. Koch): A new species of the Allochthonous dendroflora in Serbia

This paper presents the alien species Carya illinoinensis (Wangenh.) K. Koch, carya-pecan, (Juglandaceae A. Richard ex Kunth) that has not been mentioned so far in the dendroflora of Serbia. One tree was recorded within the first Serbian sugar factory in Čukarica that is now a protected cultural property in the City of Belgrade. The tree is about 35 years old and about 20 m high. The length of the trunk without branches is 6.0 m and the diameter at breast height is 57 cm. Carya-pecan is a native species of the southeastern part of North America, and is grown in Europe for edible fruits and quality wood. The recorded tree in Belgrade is fruitful and characterized by good vitality and rapid growth. Due to its special characteristics, it can have multiple practical application in the territory of Serbia for decoration in urban areas, for forest plantations and in orchards. [Projekat Ministarstva nauke Republike Srbije, br. 31041: Šumski zasadi u funkciji povećanja pošumljenosti Srbije

The importance of forest cultivation measures to protect forests from fires in Deliblato Sands (Serbia)

Na temelju organiziranog rada na pošumljavanju Deliblatske peščare u razdoblju od dva stoljeća, danas je dominantno uspostavljena faza pionirskih vrsta drveća, među kojima bagrem i borovi zauzimaju više od 90% obrasle površine, od ukupno 17.552 ha šuma. Sastojine bagrema su na površini od 11.320 ha (64,49 %), sastojine crnog i bijelog bora i ostalih četinara su na površini od 4.748 ha (27,05 %), dok ostale vrste listača (američki jasen, poljski jasen, crni orah, vrba, hrastovi, lipe, topole i dr.) zauzimaju površinu od 1.483 ha (8,45 %). U suvremenoj povijesti Deliblatske peščare, u razdoblju od 1948.-2009. godine, konstatirano je 259 požara, s ukupno opožarenom površinom 11.923 ha i opožarenom površinom šuma 6.129 ha. Ukupno opožarena površina šuma u četiri katastrofalna požara: 1973., 1990., 1996. i 2007. godine iznosila je 4.103,1 ha, a na temelju udjela opožarene površine četinjača 73,4 %, može se zaključiti da je fizički okvir za njihovu pojavu određivala površina i struktura kultura četinjača. Planska opredjeljenja u drugoj polovici dvadesetog stoljeća, na temelju kojih se zagovaralo pošumljavanje borovima na velikim površinama i održavanje velikih površina bagremom, zbog njihove ugroženosti od požara i zbog kratkih ophodnji i primjene čiste sječe u kulturama bagrema pri izdanačkom gospodarenju, nisu omogućila kontinuitet sa suvremenim ciljevima zaštite Deliblatske peščare koja danas ima status specijalnog rezervata prirode, a uslijed požara nije ostvaren očekivan biomeliorativni učinak od strane podizanih šuma. Na primjeru proučavanih srednjedobnih umjetno podignutih sastojina bijele lipe u ovom radu se ističe biološka otpornost lipe na požare, jer su u razdoblju djelovanja katastrofalnih visokih šumskih požara 1996. i 2007. godine, u kojima su potpuno uništene srednjedobne, pretežno, borove kulture na površini 1.896 hektara, sastojine bile u njihovom središtu, sačuvane i imaju kontinuitet. Na dvije trajne ogledne površine (OP-1 i OP-3) u sastojini bijele lipe s primjesama bijele topole, koja je formirana na tipu zemljišta sirozem (regosol) na rastresitom karbonatnom pijesku (stanište šume krupnolisnog medunca-Rhamneto-Quercetum virgilianae) i koja je bila u središtu katastrofalnih visokih šumskih požara 1996. i 2007. godine, u starosti 46 i 52 godine, utvrđeni su sljedeći elementi rasta za lipu: N=1962-1573 stabla po hektaru, G=37,13-38,01 m2 ha-1, V=342,02-375,00 m3 ha-1, Ivp=7,2-7,4 m3 ha-1. Sastojina od formiranja nije njegovana i na OP-1 u starosti sastojine 46 i 51 godina, na temelju dvije zakašnjele, jake, prorede ukupno je posječeno 1154 stabala lipe po hektaru ili 59 % od početnog broja, 21,26 m2 ha-1 od ukupne temeljnice (47,3 %) i 182,63 m3 ha-1 od ukupnog obujma (47,5 %). U razdoblju 46.-51. godine tekući prirast obujma preostalih stabala lipe iznosio je 11,23 m2 ha-1, u okviru kojega je prirast 184 stabla budućnosti (13,4 % stabala) iznosio 4,30 m3 ha-1 (38,3 %). Na temelju prethodno stečenih iskustava o održivosti provedenih proreda na OP-1, provedena je zakašnjela, jaka, proreda u starosti sastojine 52 godine, na OP-3, pri kojoj je ukupno posječeno 729 stabala lipe po hektaru (46,4 %), s temeljnicama 14.05 m2 ha-1 (37,0 %) i obujmom od 139.0 m3 ha-1 (37,1 %). U starosti 56 godina (2013. godine), na temelju zapažanja na terenu, struktura sastojine na prorjeđivanim pokusnim površinama je očuvana, a stabla pokazuju vidljivi stupanj revitalizacije.On the basis of organized labor in the afforestation of Deliblato Sands for a period of two centuries, today is predominantly established phase pioneer tree species, including acacia and pine trees make up over 90 % covered, from a total of 17,552 ha of forests. Locust stands are an area of ​​11,320 ha (64.49%), stands of red and white pine and other coniferous trees over an area of 4,748 ha (27.05 %), while other types of deciduous (American ash, ash, black walnut, willow, oak, linden, poplar, etc.) occupying an area of ​1,483 ha (8.45 %). In the modern history of the Deliblato Sands, in the period from 1948th to 2009th , it was found 259 fires, with a total surface affected 11,923 ha of forest areas affected by fire and 6,129 ha. The total area of ​​forests burnt by four catastrophic fires: in 1973, 1990, 1996 and 2007 amounted to 4103.1 ha, based on the share of fire-affected areas of conifers 73.4%, it can be concluded that the physical framework for their appearance determined surface structure and culture of conifers. The planned commitments in the second half of the twentieth century, on the basis of which advocated afforestation pine trees over large areas and maintenance of large areas of locust due to their fire risk due to short rotation and the application of clear cutting in the cultures locust coppice management, did not allow continuity with contemporary goals protection of Deliblato Sands, which now has the status of a special nature reserve, and as a result of the fire has not achieved the expected impact of the biomeliorative erected in the forest. For example, studied a middle artificially established stands of white lime, this article highlights the biological resistance of lime on fire, because in a period of high activity catastrophic forest fires in 1996 and 2007, which are completely destroyed middle-aged, predominantly pine culture on the surface of 1.896 hectares, stands were in their center, preserved and have continuity. Two permanent sample plots (OP-1 and OP-3) in a stand of white lime with a touch of white poplar, which was formed on the soil type sierozem (regosol) on the scattered carbonate sand (forest habitat Vergilius’ oak-Rhamneto Quercetum virgilianae) and that was at the center of catastrophic forest fires high in 1996 and 2007 at the age of 46 and 52, set out the following elements of growth for silverleaf linden: ha-1, IVP = 7.2-7.4 m3 ha-1, V = 342.02 to 375.00 m3 N = 1962-1573 trees per hectare, G = 37.13 to 38.01 m2 ha-1. The stand of the formation Nourished and the OP-1 in the stand age 46 and 51 years, on the basis of two late, strong, thinning of the linden trees cut down in 1154 per hectare, or 59 % of the original number, 21.26 ha-1 from m2 ha-1 of total volume (47.5 %). total basal area (47.3 %) and 182.63 m3 In the period 46th to 51st The ha-1, current increment of volume remaining linden trees was 11.23 m2 which included a gain 184 trees of the future (13.4 % of the trees) was ha-1 (38.3 %). 4.30 m3 Based on previous experience acquired on sustainability conducted thinning the OP-1, was carried out late, strong thinning in stand age 52, the OP-3, at which a total of 729 trees felled lime per hectare (46.4 %), with ha-1 (37.1 %). ha-1 (37.0 %) and volume of 139.0 m3 basal 14:05 m2 At the age of 56 years (2013), based on observations in the field, the structure stands on experimental area is preserved, and the trees show a visible degree of revitalization

Effect of planting density on diameter structure of black poplar clones S6-7 and M-1 - section Aigeiros [Duby]

The parameters of diameter structure of two black poplar clones in the section Aigeiros Duby (S6-7 and M-1) are presented depending on three different spacings: 3x3 m, 4.25x4.25 m and 6x6 m. Modeling of diameter structure was performed by Weibull’s function of probability distribution. We determined the effect of spacing (density) and clone both on the parameters and on the model diameter structure

Utjecaj jakih prorjeda na prirast i stabilnost stabala i sastojine smreke u starosti od 32. do 50. godine

The paper studies effects of two heavy thinnings on the increment and slenderness of various categories of trees and stability of the stand as a whole. The research was conducted on a permanent experimental plot in an Norway spruce (Picea abies /L./ Karst.) monoculture in Serbia. This monoculture was established with 5,000 seedlings per hectare on the site of mountain beech forest and the effects of heavy thinnings were investigated in the 33-40 and 41-50 age periods.To determine the thinning effects we compared current diameter increments (idt) and current height increments (iht) of dominant trees (D100 and D400) obtained by a detailed analysis of trees and of mean stand dominant trees (D100 and D400). At the stand level, we compared the current diameter (id), basal area (IG) and volume (IV) increments of all trees and of the same collective of aspirants in two periods after the thinnings, between the ages of 33 and 40, and between the ages of 41 and 50.The first thinning was carried out at the age of 32 when the dominant trees were 15 m tall and the next at the age of 40 when the dominant trees were above 20 m in height. They were both low (qd <0.85) and heavy selective thinnings (34-36% of the volume). A more significant increase in the diameter increment was recorded after the second thinning between the ages of 41 and 50. It amounted to 29.1% in aspirants and 36-42% in dominant trees (D100 and D400) compared to the period after the first thinning, i.e., between the ages of 33 and 40. The thinnings further contributed to the establishment of more favorable relations in diameter and height increments of the trees in the studied culture and thus improved their stability.Istraživanja su obavljena u kulturi smreke (Picea abies /L./ Karst.), koja je osnovana sa 5.000 sadnica po hektaru na staništu planinske šume bukve na nadmorskoj visini 870 m. Na osnovi usporedbe elemenata rasta istraživane kulture s elementima rasta u drugim mladim do srednjedobnim kulturama smreke, istraživana kultura je u kategoriji visokoproizvodnih kultura u Srbiji i šire u Europi.Na trajnoj pokusnoj plohi, u dobro sklopljenom dijelu istraživane smrekove kulture u starosti 32 godine, izmjereno je 3.911 stabala po hektaru, s volumenom od 384,17 m3·ha-1, a ukupno evidentiran prirast drvne zalihe sastojine do 40. godine iznosio je 561,85 m3·ha-1, a do 50. godine 819,1 m3·ha-1. Na osnovi dvije prorjede, u 32. i 40. godini i naknadno posječenih tanjih stabala u razdoblju od 33. do 40. god., na pokusnoj plohi ukupno je posječeno 2.844 stabla po hektaru (72,7%) volumena 279,4 m3·ha-1 (tablica 1). Numerički pokazatelji strukture stabala na pokusnoj plohi u 32., 40. i 50. godini prikazani su u tablici 2, a debljinska struktura na grafikonima 2, 3 i 4.Za definiranje utjecaja prorjeda na prirast stabala uspoređen je tečajni debljinski (idt) i visinski (iht) prirast u razdoblju od 25. do 32. godine i 33.-40. godine kod detaljno analiziranih dominantnih stabala (D100 i D400), a na sastojinskoj razini uspoređen je tečajni debljinski (idt) i visinski (iht) prirast u razdoblju od 33. do 40. godine i 41.do 50. godine kod dominantnih stabala (D100 i D400). Testiranje razlika između tečajnih prirasta u različitim razdobljima obavljeno je uz pomoć t-testa. Na razini sastojine uspoređen je i tečajni prirast promjera, temeljnice i volumena svih stabala i stabala budućnosti (311 kom.∙ha-1) u razdoblju od 33.-40. godine i u razdoblju od 41.-50. godine. Neparametrijski Kolmogorov-Smirnov test korišten je za međusobnu usporedbu struktura stupnja vitkosti (odnos h/d1,3). Istraživanja su omogućila da se definira utjecaj prorjeda na prirast i stupanj vitkosti različitih kategorija stabla i sastojine u dva starosna razdoblja sastojine, 33.-40. i 41.-50. godine. Prva prorjeda u 32. godini, pri visini dominantnih stabala 15 m, imala je karakter selektivne prorjede, bila je niska (qd<0,85) i jaka (jačina prorjede je 36% volumena). Prorjeda je obavljena u starosti sastojine koja značajnije ne odstupa od razdoblja kada se izvode prve „komercijalne“ prorjede u Europi. Međutim, tokovi tečajnog debljinskog prirasta detaljno analiziranih dominantnih stabala (D100 i D400)  pokazali su da je prekasno izvršiti prorjedu u 32. godini, a model rasta (prirasta) visina је pokazao kulminaciju u 25. godini (kada su dominantna stabla postigla visinu 11 m), pa bi se 25. godina mogla označiti i kao godina u kojoj je najkasnije trebalo izvršiti prvu komercijalnu prorjedu (grafikon 7). Zatečeni velik broj stabala, s velikom drvnom zalihom po hektaru, u 32. godini i jaka prorjeda uvjetovali su  visoki iznos prorjednog etata, od 115,13 m3∙ha-1, što je u kategoriji najviših iznosa volumena koji se okvirno preporučuju u literaturi za sličnu starost smrekovih kultura. U razdoblju od 33.-40 godine debljinski prirast je iznosio kod preostalih stabala 0,31 cm∙god-1, a kod stabala budućnosti 0,54 cm∙god.-1 (tablica 7). Dominantna stabla, posebno 400 najdebljih stabala po hektaru, nalazila su se u fazi velikog visinskog prirasta u vrijeme i poslije prorjede u 32. godini (tablica 5 i 6), što je za posljedicu imalo povećanje stupnja vitkosti stabala, odnosno povećanje nestabilnosti sastojine (grafikon 8). Druga prorjeda u 40. godini, pri visini dominantnih stabala preko 20 m, imala je karakter selektivne prorjede, bila je niska (qd<0,85) i jaka (jačina prorjede je 34% volumena). Jaka prorjeda u 40. godini, s prorjednim etatom 142,28 m3∙ha-1, uvjetovala je veći debljinski prirast, odnosno bolju reakciju debljinskog prirasta na preostalim stablima, u odnosu na prorjedu u 32. godini. Stabla budućnosti imali su za 29%, a dominantna stabala (D100 i D400) za 36-42%, veći debljinski prirast u starosnom razdoblju od 41.-50. godine, u odnosu na starosno razdoblje 33.-40. godine, što je uz opadajući trend visinskog prirasta uvjetovalo i manji stupanj vitkosti, odnosno veću stabilnost stabala i sastojine (grafikon 8).Na osnovi navedenog, proizlazi da su provedene jake prorjede doprinijele uspostavljanju povoljnih odnosa u debljinskom i visinskom rastu stabala u istraživanoj kulturi i time poboljšale njihovu stabilnost

Effects of Silvicultural Measures in Devitalized Middle Aged Oak Stand (Quercus Robur L.) on Chernozem in Vojvodina

Na dvije trajne pokusne površine (P.P.-1 i P.P.-2) u jednoj sred nje dobnoj lužnjakovoj monokulturi, analizirani su učinci različitih uzgojnih mjera, koje su poduzimane u svrhu njege sastojine i saniranja posljedica devi talizacije stabala. Proces devitalizacije utvrđen je u 42. godini starosti sastojine i manifestirao se u koincidenciji nepovoljnog sastojinskog stanja i nepovoljnih egzogenih utjecaja. Na P.P.-1 u 42. i 48. godini provedena je uzgojno-sanitar na sječa umjerenog i jakog zahvata, a na P.P.-2 uklanjana su suha stabla. Za defi niranje učinaka različitih uzgojnih mjera u starosnom razdoblju od 43–52. go-di ne, korišten je tečajni (prosječni periodički) debljinski prirast (id), svih preostalih stabala i stabala budućnosti. Na P.P.-1 srednja veličina te čajnog debljinskog prirasta svih stabala veća je za 37 %, a stabala budućno sti za 35 %, u odnosu na P.P.-2. Ovisnost debljinskog prirasta od prsnih pro mjera kod svih stabala pokazuje srednje jaku korelaciju (R = 0,52–0,54), a za grupu stabala budućnosti korelacija je slabije izražena (R = 0,28–0,32).Past experience has shown that the application of silcivultural measures to pedunculate oak stands of lessened functional capacity is met with severe restrictions for the achievement of the desired results and goals. This work analyzes the effects of different silci vultural measures in comparative permanent sample plots (P.P. -1 and P.P. -2), undertaken with the purpose of tending the stands and improving the consequences of devitalisation. Research was undertaken in an artificially established monoculture of pedunculate oak in Vojvodina (.n=45° 49’, .e=18° 39’). The altitude is 88 m, and the soil is chernozem non-carbonate, with the depth of the humus accumulative horizon of about 40–50 cm. Mean annual air temperature is 10.9 °C, and mean annual rainfall is 584 mm. During the dormant vegetation season, two cross-section diameters were measured with an accuracy of 1 mm on all trees aged 42 and 52. All the marked trees were also measured when they reached the age of 48. A silvicultural-salvage cut of moderate to heavy intensity was performed in P.P. 1 at the age of 42 and 48. A total of 128 future trees (FT) per hectare were selected in P.P.-1 at tree age 42. At the age of 52, the status was retained by 124 trees. The primary measure in P.P.-1 involved removing the strongest competition against future trees from the stand, so the treatment also had the character of selective thinning. Using similar silvicultural prin ciples, 156 dominant trees aged 42 were selected for comparison in P.P.-2. Of these, 148 trees retained the status of future trees at age 52, while P.P.-2 was left to natural tree se lection. During measurements in the year 42, a crown class (CC) and the degree of crown freedom position (CF) was determined for each tree. To assess crown damage intensity (defoliation), classification with degrees 0–4 was used. Data processing consisted of determining the numerical parameters of diameter struc ture, while the non-parametric Kolmogorov-Smirnov test (|D| statistics) was used to com pare diameter distribution with the distribution of diameter increment. The .2test for independence was used to define dependence of the degree of crown freedom position and the degree of crown defoliation, as well as the crown class and the degree of crown defo liation in sample plots at stand age 42. The effects of different stand treatments were ana lyzed in the age period 43–52. The current (average periodical) diameter increments (id) obtained with the control method was compared for all the trees in the sample plots and separately for the future trees in P.P.-1, and the comparison trees in P.P.-2. The statistical t-test was used to assess the impact of silvicultural treatments on the increment size. Growth elements of all the trees and future trees in the sample plots at age 42 and 52, as well as the trees cut at ages 42 and 48, are given in Table 1. Table 2 contains numerical indicators of their diameter distribution. Cumulative curves of diameter distribution of all the trees show that at age 42 the trees in P.P.-2 have a somewhat bigger breast diameter. Due to differential silvicultural treatments and different increment tree reactions, diame ter distribution of all the trees and future trees were approximated at age 52, which was also confirmed by the Kolmogorov-Smirnov test (Graph 1, Table 2). Based on the test for independence applied at age 42, high dependence was found in the monoculture of the degree of crown defoliation on the crown class and the degree of crown freedom position. This indicates that the devitalization process in directly linked with stand structure, i.e. silvicultural treatments in the previous period (Table 3 and 4, Figure 1). The Kolmogorov-Smirnov test confirmed the difference in diameter distribution of selec ted trees in the sample plots in the 42ndand 48thyear (Graph 2, Table 2). The thinning indi cator (qd) shows that tree selection in the sample plots had the character of low thinning. In the age period between 43 and 52, a more intensive treatment of silvicultural-sanitary cuts (P.P.-1) showed that the current diameter increment was on average higher by 37 % in all the other trees and by 35 % in future trees, in relation to the sanitary cut (Graph 3). Cumu lative curves of diameter increment in P.P.-1, for all the trees and for future trees, are shifted rightwards towards higher increment values, in relation to P.P.-2. There are also differences in the shape of the curve, which implies a difference in the variability of diameter increment (Graph 4). The Kolmogorov-Smirnov test confirmed considerable differences in the distri bution of diameter increment, both for the entire group of trees and for future trees (Table 5). Dependence of diameter increment on diameters at breast height (Graph 5 and Table 6) in all the trees shows moderate correlation ((R = 0.52-0.54), whereas correlation is less dis tinct (R = 0.28-0.32) for the collective of futures. For all the remaining trees, the impor tance of a regression coefficient of diameter increment dependence on diameters at breast height confirms that at this developmental stage the recovery from stressful impacts de pends on the intensity and character of silvicultural measures and on the tree´s increment potential. For the collective of future trees in P.P.-1 (and potentially for the group of domi nant comparison trees in P.P.-2), which are the first object of tending, recovery from adverse impacts primarily depends on the nature and intensity of silvicultural measures

Growth dynamics of crown shapes in stands of pedunculate oak and common hornbeam

Background and Purpose: Structure of crowns in forest stands is one of the main factors which determines growth and development of trees. Dynamic change occurs with the age of the stand due to silvicultural interventions or natural disturbances duringwhich trees are removed fromthe stand. The aim of this article is to analyse the structure of the crown shape of pedunculate oak and common hornbean trees with regard to diameter at breast height (DBH) and the age of the stand in one of the most important forest community in Croatia. Materials andMethods: The investigation is based on data collected on 47 permanent experimental plotswhichwere established as a chronosequence in a natural range of forests of pedunculate oak and common hornbeam in Croatia. The total surface of all plots amounts to 33.45 ha. Breast height diameter, tree height and stem height were measured on the trees in the experimental plots, and a detailed ground plan was made of horizontal crown projections, from which the crown diameters were calculated. In total 1505 pedunculate oak trees and 2026 common hornbeam trees were measured. For each tree the crown shape was calculated and trees were then grouped in age classes of 20 years, and the shape of the crown analysed according to species and age classes. Correlation between crown shapes and diameter at breast height was investigated for stands of the sixth age class (101 – 120 years) for each species by means of linear regression. Results and Discussion: The shape of the crown of pedunculate oak, although it shows a trend toward growth in relation to diameter at breast height, the regularity pattern of the shape indicates weak character (r=0.441), i.e. variability is explained with only 19%. Crown shapes of common hornbeam are almost constant in relation to diameter at breast height (r=114), and correlation between the examined values cannot be equated by any rational analytical term. Investigation of growth dynamics of crown shape structure was carried out according to the species of trees and age classes, and the interval inwhich 68%(x ± 1.0 s) and 95%of data (x ± 1.96 s)were included. Conclusions: The results of the investigation indicate that dependence on crown shape and diameter at breast height of pendunculate oak and common hornbeam cannot be described by any rational analytical term. Average values of the crown shapes according to age classes can be used as form factors for calculation of crown volume.Data are applicable in various applications, such as for example their integration in a simulator of growth and development of forest stands and examination of the effect of different silvicultural scenario

Rast i struktura linijskog zasada talijanske johe (Alnus cordata /Loisel./ Duby) u dobi 11 i 16 godina na Fruškoj gori (Srbija)

Growth and structure of Italian alder (Alnus cordata /Loisel/ Duby) trees were analyzed in a linear plantation established by planting two-year-old seedlings at Fruška Gora (Serbia). The aim of this paper is to point out the growth characteristics and the structure of the Italian alder linear plantation at age 11 and 16 years and contribute to the knowledge of adaptive and productive potential of the species in the available plantation in Serbia.The spacing between the trees was 7 m (200 trees per hectare). The plantation is located on anthropogenically changed pedunculate oak and hornbeam site at 125 m above sea level. On the basis of 35 measured trees at age 11 and 16 years, the top height was 15 and 21 m, and the Lorey’s mean height 13.4 and 19.5 m. The dominant diameter was 32.4 cm at age 11 and 59.4 cm at age 16 years. The mean quadratic diameter was 25.1 and 47 cm.The productivity of the plantation is high. At age 11 years, the basal area was 9.9 m2∙ha−1, and the standing volume 107.2 m3∙ha−1 while at age 16 years, it was 34.7 m2∙ha−1 and 305.1 m3∙ha−1, respectively. In the period from 11 to 16 years of age, the periodic annual increment in diameter was 4.4 cm∙year−1, height 1.22 m∙year−1, and in basal area and volume 4.9 m2∙ha−1·year−1and 39.6 m3·ha−1·year−1, respectively, pointing to fast growth of Italian alder.Despite the limits due to a small sample and the fact that the linear plantation was analyzed, we generalise the ­following conclusion: the measured growth characteristics at age 11 and 16 years of Italian alder trees show that the species can grow fast and could be usable in similar areas.Analizirani su rast i struktura linijskog zasada talijanske johe (Alnus cordata /Loisel/ Duby) na Fruškoj gori (Srbija). Cilj ovoga rada je da ukaže na elemente rasta i strukturu linijskog zasada talijanske johe u starosti 11 i 16 godina, i time doprinese upoznavanju adaptivnog i proizvodnog potencijala ove vrste u raspoloživom zasadu u Srbiji.Zasad je osnovan dvogodišnjim sadnicama s međusobnim razmakom 7 m, odnosno sa 200 stabala po hektaru, na antropogeno izmijenjenom staništu lužnjaka i graba, na nadmorskoj visini 125 m. Na temelju usporednog dendrometrijskog premjera 35 stabala u dobi 11 i 16 godina, dominantna visina iznosila je 15 i 21 m, a srednja visina po Loraju 13,4 i 19,5 m. Dominantni promjer iznosio je 32,4 cm u 11. godini, a 59,4 cm u 16. godini, dok je srednji promjer iznosio 25,1 cm i 47 cm. Na temelju izračuna da se po hektaru nalazi 200 stabala u 11. godini temeljnica je iznosila blizu 10 m2∙ha−1, a volumen preko 100 m3∙ha−1, a u 16. godini temeljnica je iznosila blizu 35 m2∙ha−1, a volumen preko 300 m3∙ha−1 (Tablica 1). Debljinska struktura stabala u zasadu je unimodalna u obje životne dobi (Tablica 2, Slika 1), a visinska struktura iskazana grupiranjem visina u stupnjeve širine 3 m, ima opadajući oblik u 11. godini i zvonasti unimodalni oblik u 16. godini (Tablica 3, Slika 2). Parametri modela ovisnosti visina stabala o njihovim početnim prsnim promjerima i značajke njegove ocjene ukazuju da se u dobi 11 godina 55% varijabilnosti visina može pripisati njihovim prsnim promjerima, dok je u dobi 16 godina ovisnost manje izražena (Tablica 3, Slika 3). Stupanj vitkosti opada sa starošću. U dobi 11 godina stupanj vitkosti je bio u rasponu 38–79, prosječno 54, a u dobi 16 godina u rasponu je 31–64, prosječno 43 (Tablica 4, Slika 4). U razdoblju od 11. do 16. godine tečajni prirast promjera iznosio je 4,4 cm∙god−1, visine 1,22 m∙god−1, a temeljnice i volumena po hektaru 4,9 m2∙ha−1·god−1 i 39,6 m3·ha−1·god−1 (Tablica 6). Oblik raspodjele tečajnog prirasta prsnih promjera, temeljnice i volumena stabala je sličan, sa slabo izraženom desnom asimetrijom i platikurtičnim rasporedom, a tečajni prirast visina stabala karakterizira izražena lijeva asimetrija i neizražen platikurtični raspored. U razdoblju 11.–16. godine stupanj vitkosti se prosječno smanjuje za veličinu 2,25 godišnje, uz raspon od 0,68–4,10 (Tablica 7). Zavisnost tečajnih prirasta promjera, temeljnice i volumena o njihovim početnim veličinama u 11. godini dobro opisuje linearni model, gdje se 50–70% varijabliteta može pripisati njihovim početnim veličinama. Tečajni prirast visina nije uvjetovan njihovim visinama u dobi 11 godina. Međutim, promjena stupnja vitkosti u razdoblju 11–16 godina ima jasno izražen negativan linearan trend, odnosno stabla s većim stupnjem vitkosti u dobi 11 godina također su imala i veći pad (Tablica 8). Uz sva ograničenja za generalizaciju zaključaka zbog malog uzorka stabala i linijskog zasada značajke rasta u 11. i 16. godini dobi ukazuju da talijanska joha ima karakteristike brzog rasta i može predstavljati potencijalno primjenjivu vrstu u sličnim područjima

Effects of two different thinning methods on the diameter and basal area increments of silver lime (Tilia tomentosa Moench) target trees in Fruška Gora (Serbia)

This paper analyses the cumulative effects of selective thinning and thinning from below on diameter and basal area increments of target trees after 25/26 years in 52, 69- and 86-year-old silver lime (Tilia tomentosa Moench) stands. Two target tree collectives were analysed: (1) elite trees selected between 1993–1994 from permanent sampling plots (selective thinning method), and (2) a ‘comparable collective’ of target trees selected in 2019 (25/26 years later) according to the same criteria as the elite trees, in the same stands thinned from below. Elite trees that were selectively thinned had: higher diameter, basal area and volume per tree, higher diameter and basal area increment for a given time period, and lower slenderness coefficients compared to the target trees that were thinned from below at 52 and 69 yr. While diameter increment decreases with age, and differences between elite trees of different ages are clearly delineated, diameter increments of trees thinned from below are not significantly different at 52 and 69 yr. In addition, basal area increment of trees is highest at 69 yr with selective thinning. When thinning from below, there were no significant differences in basal area increments between trees at 69 and 86 yr. Silver lime shows a strong growth response after selective thinning at ages 25/26 and 44 yr. However, our results show that this response is less pronounced when selective thinning begins at 61 yr