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

Effects of Thinning in a Plantation of Poplar Clone I-214 withWide Spacing

U nasadu topole klona I-214, osnovanom pri razmaku sadnje 6 × 6 m u sistemu kvadratne veze na zemljištu srednje povoljnom za uzgoj topola, analizirani su učinci prorjede koja je izvedena 11 godina nakon osnivanja nasada. Prorjeda je imala selektivan karakter, odnosno izdvojena je grupa tzv. perspektivnih stabala u broju koji odgovara prosječnom razmaku od 8,5 × 8,5 m i uklonjeni su njihovi izraziti konkurenti. Uzgojno neperspektivna stabla i stabla zaostala u rastu, što je uglavnom posljedica naknadnih popunjavanja, također su uklonjena. Prorjedom su uklonjena 122 stabla po hektaru (46 %), 6,45 m2/ha (43 %), 66,08 m3/ha (42 %) i 2645 m2/ha (40 %) površine projekcije krošnje, što je jačina zahvata iznad tzv. kritične temeljnice. Sortimentna struktura prorjednog etata pri selektivnoj prorjedi povoljnija je od shematskih prorjeda u mlađim nasadima na povoljnijim staništima i daje 50 % tehničkog drva, 30 % celuloznog drva i 20 % otpatka. Nakon 5 godina na prorijeđenoj je površini srednji promjer po temeljnici veći za 10,6 %, volumen srednjeg stabla veći je za 21,9 %, a površina projekcije krošnje srednjeg stabla veća je za 59,0 % u odnosu na neprorijeđenu površinu. Nasuprot tomu, srednja visina po Loraju na prorijeđenoj je površini za 4,2 % manja u odnosu na neprorijeđenu površinu. Veći tečajni prirast promjera, volumena i površine projekcije krošnje stabala na prorijeđenoj površini ukazuje na mogućnost produžetka ophodnje i povoljniju sortimentnu strukturu u odnosu na kontrolnu površinu.Research was conducted in the experiment plot of euramerican poplar, clone I-214, which was founded with one year seedling type 1/1 with spacing 6 × 6 m in the square system on the alluvial soils of river Sava basin in which browning processes is expressed. Eleven years after the plantation establishment 3 blocks with two experimental plot of 0.2016 ha, which are separated by a so-called. protective order, were singled out. In the experimental plot all the trees were numbered and measured by two cross-dbh, with an accuracy of 1 mm, and height, with an accuracy of 1 dm. The crown projection radius of 8 positions, each rotated to 45o, were measured. On the three experimental plots (one in each block) selective thinning was carried out (PP-E), at which in each plots 50 % of trees were cut down, or the distance between the trees raised on average 8.5 × 8.5 m. Firstly, a collective called. promising trees set aside, in the number that corresponds to an average distance of 8.5 × 8.5 m, and their main competitors were removed. The trees behind in development, which is mainly due to additional filling in plantations two years after planting, are also removed because they were judged as silvicutural non-perspective. The remaining three experimental plots were control (PP-K). In each repetition trees for dendrometric analysis were sampled, the dominant one (dg20%) and a mean tree which has mean quadratic diameter (dg). In the 16thyears of plantation development diameters at breast height (dbh) and height of each tree were re-measured, sa well as crown projection radius. The development of mean and dominant trees showed that the investigated habitat is the medium favorable for the cultivation of the poplar clone I-214. Current increment of diameter, height and volume in the 11thyear was in the intensive phase, where volume increment has not yet culminated (Figure 1–3). As a suitable element of growth to determine the start of thinning operation on a biological point of view, can be ring width along the spindle tree. In the first five years the tree has had a full solitary growth, and from the seventh year there is a competitive relationship between trees in plantation, which is manifested by changing the ring width along the spindle tree (Figure 4 and 5). This means that before the seventh year thinning does not have any biological justification. Models 1 and 2 of volume tables, constructed measuring felled trees from thinning (Table 2), and which are the dependence of the volume of tree from diameter at breast height (model 1) and from the diameter at breast and height (model 2), proved to be equally good at calculating the volume per hectare in the 11thyear and more convenient compared to other tables and models (Table 3). To calculate the volume in the 16thyear two input volume tables can be successfully used (model 2), while the application of model 1 is limited at the 11thyear. In the 11th year at the experimental plot an average of 263–266 trees per hectare are found, which represents a survival rate of about 95 %. Total basal area averaged from 14.70 to 14.97 m2/ha, while volume was an average from 156.67 to 157.62 m3·ha-1. By applying the statistical t-test significant difference in the number of trees, basal area and volume per hectare was not determined within the experimental plots before applying the silvicultural treatments (Table 4). By applying thinning operation,122 trees per hectare (46%), 6.45 m2/ha (43 %) of the total basal area, 66.08 m3/ha (42%) of the total volume and 2645 m2/ha (40 %) of the the crown projection area were removed, which represent a strong procedure and is located above the so-called. critical basal area (Table 4, 13).Size of allowable cut in the thinning of 66.08 m3/ha was in the limits expected on the basis of previous research for the density of 278 trees per hectare and the habitat medium favorable for the development of poplar clone I-214. However, the assortment structureof allowable cut is more favorable compared to thinning in younger plantations in the more favorable habitats and produces 50 % of technical wood, 30% of pulpwood and 20 % of wastewood (Table 4, 9, 15). Between 11 and 16 years on both series of experimental plot the mortality of trees was not determined. Five years after application of thinning treatment a significant difference in the number of trees, basal area, volume and crown projection areas of trees per hectarewere determined between the experimental and control plots (Table 4). The significant difference in the mean diameters, heights and crown projection areas of the mean and the dominant trees (Table 5, 6), as well as between the diameter strucures (Figure 7) were also determined between investigated plots. For a period of 5 years after application of thinning operation at the experimental field current basal area and volume increment per hectare accounted 85 % of basal area increment and 75 % of volume increment of the control plots wich had the number of trees twice higher than experimental plots (Table 14). For five years of positive reactions to increase growing space of remaining trees on the experimental plots the size of the total basal area and volume of trees removed by thinning operation is not compensated: the total basal area and the volume per hectare amounted to 2/3, and the crown projection area amounted 87 % of the size of the control plot. The reaction of trees on experimental plot with thinning treatment for 5 years is great and is reflected in greater mean diameter by 10.6 %, greater mean tree volume by 21.9 % and increased the crown projection area by 59.0 % compared to control plot. In contrast, the mean Lorey’s height at the experimental plot with thinning treatment decreased by 4.2 % compared to control plot. This has contributed to the intensification of the current (average periodic) volume increment compared to the period before applying thinning operation. Greater assimilation apparatus of trees in the experimental plots with thinning tretament and higher current diameter and volume increment indicate the need to extend the production cycle at the best assortment structure compared to the control plot. The research results indicate the validity of efforts that the thinning operation in poplar plantations should be treated as a biological and an economic category. As a biological category the thinning operation contributes to accelerating the growth of the remaining phenotypically better established trees and achieve optimum production. As economic categories with thinning operation realized the previous crop, and it being understood that the assortment of allowable cut in the thinning cover cost cutting and the establishment of plantations with more trees. In this framework it is necessary to direct further research, because the poplar plantations,which are aimed to applying thinning operation, are flexible enough to allow adaptation to changing market conditions

Effects of Thinning in a Plantation of Poplar Clone I-214 withWide Spacing

U nasadu topole klona I-214, osnovanom pri razmaku sadnje 6 × 6 m u sistemu kvadratne veze na zemljištu srednje povoljnom za uzgoj topola, analizirani su učinci prorjede koja je izvedena 11 godina nakon osnivanja nasada. Prorjeda je imala selektivan karakter, odnosno izdvojena je grupa tzv. perspektivnih stabala u broju koji odgovara prosječnom razmaku od 8,5 × 8,5 m i uklonjeni su njihovi izraziti konkurenti. Uzgojno neperspektivna stabla i stabla zaostala u rastu, što je uglavnom posljedica naknadnih popunjavanja, također su uklonjena. Prorjedom su uklonjena 122 stabla po hektaru (46 %), 6,45 m2/ha (43 %), 66,08 m3/ha (42 %) i 2645 m2/ha (40 %) površine projekcije krošnje, što je jačina zahvata iznad tzv. kritične temeljnice. Sortimentna struktura prorjednog etata pri selektivnoj prorjedi povoljnija je od shematskih prorjeda u mlađim nasadima na povoljnijim staništima i daje 50 % tehničkog drva, 30 % celuloznog drva i 20 % otpatka. Nakon 5 godina na prorijeđenoj je površini srednji promjer po temeljnici veći za 10,6 %, volumen srednjeg stabla veći je za 21,9 %, a površina projekcije krošnje srednjeg stabla veća je za 59,0 % u odnosu na neprorijeđenu površinu. Nasuprot tomu, srednja visina po Loraju na prorijeđenoj je površini za 4,2 % manja u odnosu na neprorijeđenu površinu. Veći tečajni prirast promjera, volumena i površine projekcije krošnje stabala na prorijeđenoj površini ukazuje na mogućnost produžetka ophodnje i povoljniju sortimentnu strukturu u odnosu na kontrolnu površinu.Research was conducted in the experiment plot of euramerican poplar, clone I-214, which was founded with one year seedling type 1/1 with spacing 6 × 6 m in the square system on the alluvial soils of river Sava basin in which browning processes is expressed. Eleven years after the plantation establishment 3 blocks with two experimental plot of 0.2016 ha, which are separated by a so-called. protective order, were singled out. In the experimental plot all the trees were numbered and measured by two cross-dbh, with an accuracy of 1 mm, and height, with an accuracy of 1 dm. The crown projection radius of 8 positions, each rotated to 45o, were measured. On the three experimental plots (one in each block) selective thinning was carried out (PP-E), at which in each plots 50 % of trees were cut down, or the distance between the trees raised on average 8.5 × 8.5 m. Firstly, a collective called. promising trees set aside, in the number that corresponds to an average distance of 8.5 × 8.5 m, and their main competitors were removed. The trees behind in development, which is mainly due to additional filling in plantations two years after planting, are also removed because they were judged as silvicutural non-perspective. The remaining three experimental plots were control (PP-K). In each repetition trees for dendrometric analysis were sampled, the dominant one (dg20%) and a mean tree which has mean quadratic diameter (dg). In the 16thyears of plantation development diameters at breast height (dbh) and height of each tree were re-measured, sa well as crown projection radius. The development of mean and dominant trees showed that the investigated habitat is the medium favorable for the cultivation of the poplar clone I-214. Current increment of diameter, height and volume in the 11thyear was in the intensive phase, where volume increment has not yet culminated (Figure 1–3). As a suitable element of growth to determine the start of thinning operation on a biological point of view, can be ring width along the spindle tree. In the first five years the tree has had a full solitary growth, and from the seventh year there is a competitive relationship between trees in plantation, which is manifested by changing the ring width along the spindle tree (Figure 4 and 5). This means that before the seventh year thinning does not have any biological justification. Models 1 and 2 of volume tables, constructed measuring felled trees from thinning (Table 2), and which are the dependence of the volume of tree from diameter at breast height (model 1) and from the diameter at breast and height (model 2), proved to be equally good at calculating the volume per hectare in the 11thyear and more convenient compared to other tables and models (Table 3). To calculate the volume in the 16thyear two input volume tables can be successfully used (model 2), while the application of model 1 is limited at the 11thyear. In the 11th year at the experimental plot an average of 263–266 trees per hectare are found, which represents a survival rate of about 95 %. Total basal area averaged from 14.70 to 14.97 m2/ha, while volume was an average from 156.67 to 157.62 m3·ha-1. By applying the statistical t-test significant difference in the number of trees, basal area and volume per hectare was not determined within the experimental plots before applying the silvicultural treatments (Table 4). By applying thinning operation,122 trees per hectare (46%), 6.45 m2/ha (43 %) of the total basal area, 66.08 m3/ha (42%) of the total volume and 2645 m2/ha (40 %) of the the crown projection area were removed, which represent a strong procedure and is located above the so-called. critical basal area (Table 4, 13).Size of allowable cut in the thinning of 66.08 m3/ha was in the limits expected on the basis of previous research for the density of 278 trees per hectare and the habitat medium favorable for the development of poplar clone I-214. However, the assortment structureof allowable cut is more favorable compared to thinning in younger plantations in the more favorable habitats and produces 50 % of technical wood, 30% of pulpwood and 20 % of wastewood (Table 4, 9, 15). Between 11 and 16 years on both series of experimental plot the mortality of trees was not determined. Five years after application of thinning treatment a significant difference in the number of trees, basal area, volume and crown projection areas of trees per hectarewere determined between the experimental and control plots (Table 4). The significant difference in the mean diameters, heights and crown projection areas of the mean and the dominant trees (Table 5, 6), as well as between the diameter strucures (Figure 7) were also determined between investigated plots. For a period of 5 years after application of thinning operation at the experimental field current basal area and volume increment per hectare accounted 85 % of basal area increment and 75 % of volume increment of the control plots wich had the number of trees twice higher than experimental plots (Table 14). For five years of positive reactions to increase growing space of remaining trees on the experimental plots the size of the total basal area and volume of trees removed by thinning operation is not compensated: the total basal area and the volume per hectare amounted to 2/3, and the crown projection area amounted 87 % of the size of the control plot. The reaction of trees on experimental plot with thinning treatment for 5 years is great and is reflected in greater mean diameter by 10.6 %, greater mean tree volume by 21.9 % and increased the crown projection area by 59.0 % compared to control plot. In contrast, the mean Lorey’s height at the experimental plot with thinning treatment decreased by 4.2 % compared to control plot. This has contributed to the intensification of the current (average periodic) volume increment compared to the period before applying thinning operation. Greater assimilation apparatus of trees in the experimental plots with thinning tretament and higher current diameter and volume increment indicate the need to extend the production cycle at the best assortment structure compared to the control plot. The research results indicate the validity of efforts that the thinning operation in poplar plantations should be treated as a biological and an economic category. As a biological category the thinning operation contributes to accelerating the growth of the remaining phenotypically better established trees and achieve optimum production. As economic categories with thinning operation realized the previous crop, and it being understood that the assortment of allowable cut in the thinning cover cost cutting and the establishment of plantations with more trees. In this framework it is necessary to direct further research, because the poplar plantations,which are aimed to applying thinning operation, are flexible enough to allow adaptation to changing market conditions

The Effect of Silver Ion, 1-Naphthalene Acetic Acid and 6-Benzylaminopurine on Micropropagation of "Fastigiate" Tree Shape Variety Populus alba cl. LBM

In this work the effects of silver ion, 1-Naphthalene acetic acid (NAA) and 6-Benzylaminopurine (BAP) and their interactions on micropropagation of Populus alba cl. LBM, male genotype with fastigiate tree shape were studied. Three concentrations of silver nitrate [(Ag NO3), (0, 1.0 and 2.0 mu M)], two concentrations of NAA (0 and 0.1 mu M) and three concentrations of BAP (0, 0.5 and 2 mu M) were added to solidified Aspen culture (AC) media containing 2.0 mu M of kinetin and 10 g L-1 sucrose. Three traits were examined: percentage rooting, percentage microshoots with new shoots and the ratio of shoot length increment within the first and fourth week and length after the first week. The results showed a significant effect of NAA concentration on all the examined traits. The main effects of all examined factors and the interaction between different concentrations of three growth regulators had a significant effect on rooting and multiplication percentage. The inclusion of NAA in the medium at a concentration of 0.1 mu M stimulated multiplication and suppressed shoot growth and rooting, while BAP had the opposite effect. Silver ions stimulated both shoot multiplication and rooting, thus suggesting that it masked the effects of endogenous inhibitors such as ethylene

Effect of planting density on the development of tree and plantation volume of Populus x euramericana (Dode) Guinier cl. I-214

The effect of plantation density on the stem volume development phases of mean trees of Populus x euramericana (Dode) Guinier, cl. I-214 were studied in the test plantation aged 25 years with two different planting densities 4.25x4.25 m (treatment A) and 6.00x6.00 m (treatment B). The modeling of stem volume growth of mean trees enabled the identification of development phases based on biological laws. Different growth dynamics of mean trees of the clone I-214, depending on plantation density, had a clear effect on the beginning and the end of individual phases, i.e. subphases of development, as well as on the diameters, heights and volumes of mean trees at the end of each phase of volume development

Diameter structure modeling and the calculation of plantation volume of black poplar clones

A method of diameter structure modeling was applied in the calculation of plantation (stand) volume of two black poplar clones in the section Aigeiros (Duby): 618 (Lux) and S1-8. Diameter structure modeling by Weibull function makes it possible to calculate the plantation volume by volume line. Based on the comparison of the proposed method with the existing methods, the obtained error of plantation volume was less than 2%. Diameter structure modeling and the calculation of plantation volume by diameter structure model, by the regularity of diameter distribution, enables a better analysis of the production level and assortment structure and it can be used in the construction of yield and increment tables

PRODUKCIJA BIOMASE I ENERGETSKI POTENCIJAL NEKIH KLONOVA CRNE TOPOLE (Populus deltoides Bartr. ex Marsh.) U ODNOSU NA RAZMAK SADNJE

AbstractThe possibility of biomass production was studied in an experimental trial stand with four clones of Eastern cottonwood Populus deltoides Bartr. ex Marsh. cl.457, cl.450, cl.618 and cl. 55/65 and three stand densities a) 1.2 × 1.0 m (8330 plants·ha–1), b) 1.2 × 0.75 m (11110 plants·ha–1) and c) 1.2 × 0.5 m (16600 plants·ha–1). Field trials were conducted on sandy-loamy form of fluvisol.Total determined volume of trunk, bark, and branches in the first two-year cycle for the used Eastern cottonwood ranged from 27.391 m3·ha–1 in clone 450 at planting distance of 1.2 × 1.0 m, subtreatment (a) to 42.006 m3·ha–1 in clone 618, subtreatment (c) at planting distance of 1.2 × 0.5 m. After renovation of stand using the regeneration force of shoots from the tree stumps the produced wood mass in the second two-year cycle ranged from 54.664 m3·ha–1 in clone 55/65, subtreatment (a) to 79.235 m3·ha–1 in clone 450, subtreatment (b).In additon to clone selection a significant influence on biomass yeald was also exerted by stand density (number of plants·ha–1).The largest amount of heat energy would be obtained in subtreatment (c) at density of 1.20 × 0.5 m by combustion of biomass of above ground part of clone 55/65: 364.02 GJ·ha–1 in the first cycle, and 659.83 GJ·ha–1 in the second, or a total of 1023.85 GJ·ha–1.U cilju iznalaženja najpovoljnije tehnologije proizvodnje biomase za energetske potrebe, istraživanja su obavljena na Pokusnom dobru Instituta za nizijsko šumarstvo i životnu sredinu u neposrednoj blizini Novoga Sada u nasadima sa dvogodišnjim proizvodnim ciklusom, u poljskim uvjetima sa četiri klona i tri razmaka sadnje u dva turnusa. Klonovi u pokusu pripadaju američkoj crnoj topoli (Populus deltoides Bartr. ex Marsh.): cl. 457, cl. 450, cl. 618, cl. 55/65. Razmaci sadnje su: (a) 1,20 × 1,00 m ili 8.330 biljaka·ha–1; (b) 1,20 × 0,75 m ili 11.110 biljaka·ha–1 i (c) 1,20 × 0,50 m ili 16.660 biljaka·ha–1.Zemljište na kojemu su obavljena istraživanja sustavno pripada tipu fluvisol, formi ilovastoj. Ovo zemljište je cijelom dubinom karbonatno i oglejano, vrlo duboko, sa fiziološki aktivnom dubinom oko 200 cm. Morfološka građa ovoga zemljišta je Amo,p-IGso-IIGso-IIIGso-IVGso-Gr. Humusno akumulativni horizont (A-horizont) u teksturnom pogledu je ilovača, debljine 30 cm i ona je glavni nositelj fiziološke aktivnosti, sa sadržajem humusa preko 2,3 %. S dubinom se mijenja teksturni sastav, uglavnom raste udio frakcija pijeska, a opada udio humusa, što upućuje na akumulativni tip rasporeda organske materije u profilu. Podzemna voda oscilira na dubini od 90 do 220, cm što omogućuje povoljno vlaženje fiziološki aktivnog dijela profila, tj. aktivne zone rizosfere.U ispitanom području klima je umjereno kontinentalna, s izvjesnim specifičnostima. Najhladniji mjesec je siječanj sa srednjom temperaturom zraka od –1,1 °C, najtopliji lipanj sa 20,3 °C, a srednja godišnja temperatura zraka je 10,9 °C. Prosječna količina padavina za područje na kojemu su obavljena istraživanja je 592 mm. Od prosječne godišnje količine padalina u vegetacijskom periodu padne 333 mm ili 56 %.Prvi turnus je osnovan s reznicama dužine 20–25 cm, koje su predhodno potapane u vodi 24 sata.U pogledu postotka primanja reznica nema statistički značajnih razlika i prosjek primanja za sve klonove iznosi 91,6%. Najmanji je postotak prijema (89 %) kod klona 618 zatim klona 450 (91 %), dok su klonovi 457 i 55/65 imali postotak prijema od 93 %.Na kraju prvog dvogodišnjeg turnusa promjeri se nalaze u intervalu od 2,9 cm do 3,7 cm, a visine od 5,4 m do 6,2 m. Analize varijanci za promjere pokazuju da u prvom turnusu nema statistički značajnih razlika između klonova (glavni tretmani). Međutim, razlike u promjerima koje su uvjetovane različitim gustoćama nasada (podtretmani) statistički su vrlo značajne. U prvom turnusu među klonovima postoje statistički značajne razlike u visinama, što je uvjetovano genetskom varijabilnošću klonova, dok su u borbi za životnim prostorom (razmaci sadnje) razlike u visinama statistički vrlo značajne.Analiza varijanci srednjih vrijednosti, na kraju drugog turnusa, ukazuju da su razlike i za promjere i za visine signifikantno različite. Kod svih klonova najveće dimenzije postignute su u razmacima sadnje 1,20 × 1,0 m, a najmanje u razmacima 1,2 × 0,5 m. U drugom turnusu, zbog jačine izbojne snage, svi klonovi bilježe znatno više vrijednosti promjera i visina. Promjeri se nalaze u intervalu od 3,9 cm do 5,1 cm, a visine od 6,6 m do 7,5 m.Ukupno utvrđena masa drveta, kore i granjevine u prvom dvogodišnjem turnusu za korištene klonove američke crne topole Populus deltoides Bartr. ex Marsh. nalazi se u intervalu od 27,391 m3·ha–1 kod klona 450 u podtretmanu (a) pri razmaku 1,2 × 1,0 m, do 42,006 m3·ha–1 kod klona 618 u podtretmanu (c) pri razmaku sadnje 1,2 × 0,5 m.Obnavljanje pokusnog nasada izvršeno je korištenjem izbojne snage iz panjeva. Tijekom prvog vegetacijskog razdoblja obnove iz panja izvršena je redukcija izbojaka, na način što je ostavljen po jedan najbolje razvijen izbojak na svakom panju.Obnavljanjem nasada putem izdanačke moći iz panjeva proizvedena drvna masa u drugom dvogodišnjem turnusu nalazi se u intervalu od 54,664 m3·ha–1 kod klona 55/65 u podtretmanu (a), do 79,235 m3·ha–1 kod klona 450 u podtretmanu (c).Rezultati ovih istraživanja potvrđuju realnu mogućnost obnavljanja nasada topola guste sadnje korištenjem izdanačke moći panjeva nakon sječe. Kod osnivanja nasada ovog tipa posebnu pozornost treba posvetiti izboru klona, sa svojstvima brzog rasta u juvenilnoj fazi razvoja i genetskim svojstvima regeneracije panjeva nakon sječe, kao mogućnosti obnavljanja nasada putem izbojaka iz panjeva u više turnusa. To pokazuju i razlike u proizvedenoj masi koja je za 49,7 % veća u drugom nego u prvom turnusu, u prosjeku za sve klonove i sve razmake sadnje.Na temelju proizvedene mase i vrijednosti volumne mase drveta procijenjena je težina biomase. Na kraju prvog dvogodišnjeg turnusa težina biomase nalazi se u intervalu od 10,35 t·ha–1 kod klona 618 pri gustoći 1,20 × 1,00 m, do 18,68 t·ha–1 kod klona 55/65 pri gustoći 1,20 × 0,50 m. U drugom turnusu, zbog jačine izbojne snage, težina biomase nalazi se u intervalu od 22,54 t·ha–1 kod klona 618 pri gustoći 1,20 × 1,00 m, do 33,86 t·ha–1 kod klona 55/65 pri gustoći 1,20 × 0,50 m.Da bi se mogla izvršiti procjena količine energije koja se dobija potpunom sječom stabala poslije prvog i poslije drugog dvogodišnjeg turnusa, određene su kalorične vrijednosti gornje toplinske moći za uzorke drveta i kore ispitivanih klonova prema standardnoj metodologiji u kalorimetrijskoj bombi.Kalorične vrijednosti drveta i kore ispitanih klonova nalaze se u intervalu od 18,542 MJ·kg–1 kod klona 457 do 19,554 MJ·kg–1 kod klona 618.Energetska vrijednost biomase neposredno je povezana s toplinskom moći drveta korištenih klonova, ali i s ostalim čimbenicima koji utječu na količinu i kvalitetu proizvedene biomase. Iz ovih podataka je vidljivo da je značajno veća količina energije proizvedena u drugom turnusu u odnosu na prvi, što je rezultat boljeg zakorjenjivanja i jake izbojne moći odabranih klonova.Najveća količina toplinske energije dobila bi se u podtretmanu (c) pri gustoći 1,20 × 0,50 m, sagorijevanjem biomase nadzemnog dijela klona 55/65 i to 364,02 GJ·ha–1 u prvom turnusu, 659,83 GJ·ha–1 u drugom turnusu ili ukupno 1.023,85 GJ·ha–1.U okviru grupe korištenih klonova američke crne topole Populus deltoides Bartr. ex Marsh. minimalna količina toplinske energije bi se osigurala u podtretmanu (a) pri gustoći 1,20 × 1,00 m sagorijevanjem nadzemnog dijela biomase kod klona 618 i to 202,38 GJ·ha–1 u prvom turnusu, 440,75 GJ·ha–1 u drugom turnusu ili ukupno 643,13 GJ·ha–1

Productivity of black locust (Robinia pseudoacacia L.) stands on chernozem in Vojvodina

This paper presents the elements of growth of black locust trees and stands in 15 sample plots in Vojvodina, at the age of 21-68 years. In each sample plot, based on soil profile horizons the determined soil type was chernozem as well as its lower systematic units (subtype, variety and form), according to the Škorić et al. (1985) classification. On the basis of the mean stand heights (hL), the stands on the subtype of chernozem on loess and loesslike sediments belong to height classes I-IV, and stands on calcareous aeolian sand to classes II-V (according to R e d e i et al. 2014), which indicates their considerable variability with respect to productivity within the determined subtypes of chernozem. Significant differences at the level of chernozem subtypes were found between the mean heights (p = 0.032), but not between the mean diameters (p = 0.083). The mean diameters at breast height in the studied black locust stands were on average lower than the models of diameter growth for the appropriate height classes and determined by a larger number of trees per hectare than in the tables (R e d e i et al, 2014). The volume per hectare is higher than in the tables also being conditioned by the large number of trees per hectare. [Projekat Ministarstva nauke Republike Srbije, br. III43007: Istraživanje klimatskih promena na životnu sredinu: praćenje uticaja, adaptacija i ublažavanje

Early shoot and root growth dynamics as indicators for the survival of black poplar cuttings

The relationship between early root and shoot formation at the beginning of the vegetation period and cutting survival on sandy and loamy fluvisol for 14 genotypes of black poplars was analyzed. Considerable cutting mortality was observed only within the first 80 days since planting. Intensive root formation in the first 20 days since the planting and vigorous shoot growth and development in subsequent 20 days was observed in easy-to-root genotypes. Coefficients of correlation revealed close relationship between early root and shoot growth and development and cutting survival of tested genotypes. The obtained results could be used in the breeding process, as well as for the design of cultivar-adjusted nursery and plantation establishment technology. Tested shoot characteristics, were found to be especially interesting since they could be measured rapidly, by non-destructive means

Elements of structure and productivity of clone I-214 (Populus×euramericana (Dode) Guinier) plantations on the river Sava alluvium

Two experimental plantations of Euramerican poplar (Populus×euramericana (Dode) Guinier) - clone I-214 were researched on the river Sava alluvium in Srem. Three sample plots were established in each of the plantations, aged 31 years. The soil type was humofluvisol (alluvial semigley), planting space 6×6 m. The plantations were established with 278 rooted cuttings per hectare, and the number of trees at the age of 31 accounted for 46.5-60.6%. The constructed height curves, mean stand height (hg) and upper (hg20%) heights show that the study plantations were established on different site classes, which was significantly reflected on other plantation growth elements and productivity. However, there was no significant effect of site class on the variability (sd and cv) and shape of diameter structure (α3 and α4). The constructed models of diameter structure for each site class (by Weibull function) differ by location parameter (a), and do not differ by parameter of scale (b) and shape (c). The tree and plantation growth elements show a high production potential of the clone I-214 which indicates that, on optimal soils and with the provided technological measures in the stage of nursery production and in the stage of plantation establishment, clone I-214 presents the good base for high production effects