GROWTH CHARACTERISTICS OF SOME BLACK POPLAR CLONES

U poljskom pokusu osnovanom pri gustoći od 400 stabala·ha-1 u zaštićenom dijelu vlažnog zemljišta, tipa fluvisol, srednjeg Podunavlja, pjeskovito-ilovaste forme, istraživane su karakteristike rasta tri klona (sorte) crnih topola: "PE 19/66", "S6-7" i "M-1" starosti 11 godina. Karakteristike rasta promjera, visine i volumena srednjih stabala ukazuju na značaj izbora klona (sorte) crnih topola pri osnivanju nasada za razlčite namjene: klonovi "PE 19/66" i "S6-7" (Populus deltoides Bartr.) u istraživanim uvjetima staništa i gustoće postižu kulminaciju prosječnog prirasta volumena u starosti od 11 godina, pri čemu se postiže drvna masa od 220-290 m3·ha-1 namijenjenog za kombiniranu proizvodnju tehničkog i celuloznog drveta. Sorta "M1" (Populus × euramericana (Dode) Guinier) za 11 godina postiže kulminaciju tekućeg prirasta volumena te se procjenjuje znatno duži proizvodni ciklus i kvalitetnija struktura dobijenih sortimenata.Growth characteristics of three black poplar clones, PE 19/66, S6-7, and M-1, were investigated in the field experiment established at plant distance of 5m x 5m in the protected area of central Danube basin, on the fluvisol of sandy-clayey form, after ten years of culture development. The characteristics of diameter, height and volume growth of medium trees show significant differences among the investigated black poplar clones. The research clearly highlights the significance of the clone (species) of black poplar at establishing the plantation for different purposes: clones PE 19/66 and S6-7, (Populus deltoides Bartr.) under the research conditions of the habitat and planting distance reach the culmination of average volume increment 11 years since the beginning of planting, reaching a wood volume of 220-290 m3·ha-1 for the purposes of combined production of technical and pulp timber. Clone M-1, a hybrid of domestic and American black poplar (Populus x euramericana (Dode) Guinier), demonstrates different growth properties, while the culmination of average volume increment at age 15 since the planting is estimated to have a considerably better assortment structure

Effects of heavy thinning on Turkey oak (Quercus cerris L.) tree and stand increment

Na trajnim pokusnim plohama u umjetno podignutoj, srednjedobnoj, sastojini cera analizirani su efekti jake prorede na prirast stabala i sastojine, 5 i 10 godina od izvođenja. U 56. godini na pokusnoj plohi 1 (jaka proreda) prirašćivalo je 62% stabala, a na plohi 2 (sanitarna sječa) prirašćivalo je 95% stabala u odnosu na početno stanje u 46. godini. Pet godina poslije jake prorede na O.P.-1 tekući prirast temeljnice po hektaru iznosio je 89%, a zapremine 88%, u odnosu na (O.P.-2). U narednom petogodišnjem periodu tekući prirast temeljnice istih stabala na O.P.-1 iznosio je 95 %, a zapremine 92 %, u odnosu na O.P.-2. U cjelokupnom promatranom periodu tekući prirast temeljnice i zapremine preostalih stabala po hektaru na O.P.-1 iznosio je 92 %, odnosno 90 %, u odnosu na O.P.-2. Tekući prirast promjera, temeljnice i zapremine po stablu na O.P.-1. u prvom petogodišnjem periodu bio je veći za 21-22%, u drugom petogodišnjem periodu bio je veći za 26-30%, a u cjelokupnom promatranom periodu bio je veći za 23-25%, u odnosu na O.P.-2. Posle 10 godina na O.P.-1 srednji promjer preostalih stabala povećan je za 16,1%, temeljnica za 34,7%, a zapremina za 50,8%. Za isti period na O.P.-2 srednji promjer preostalih stabala povećan je za 13,2%, temeljnica za 28,4%, a zapremina za 40,4%. Zaključak je kako je jaka proreda povoljno utjecala na povećanje prirasta preostalih stabala. Ukupna produkcija na pokusnim plohama u 56. godini, pored isključivanja 38 % stabala iz proizvodnje na O.P.-1, približno je identična i održan je uspostavljeni rang (sa manjom razlikom) u veličini ukupne produkcije između oglednih ploha pre jake prorede.On permanent sample plots in middle-aged, artificially established, Turkey oak stand, the effects of heavy thinning (S.P.-1) and sanitation cutting (S.P.-2) were analysed on trees and stand increment, 5 and 10 years after cutting at the age of 46 years. Till the age of 56 years, 62% trees incremented on S.P.-1, and 95% trees on S.P.-2, compared to the initial state at the age of 46 years. Due to the devitalisation in the previous period, the remaining trees had the reduced capacity of growth reaction to the spatial increase and they compensated the increment loss slowly, which resulted due to the reduction of a great number of trees (38%) and volume (31%) on S.P.-1. Five years after heavy thinning on S.P.-1 the compensated volume was 57.4 % compared to the state before thinning, and after 10 years, the volume increased by 10% compared to the state before thinning. Compared to the volume per ha on S.P.-2 at the age of 56 years, the volume on S.P.-1 was lower by 20.6%. However, total production on sample plots at the age of 56 years, regardless of the elimination of 38% trees on S.P.-1, was approximately identical, and the established rank was maintained (with minor differences) in the size of the total production between the sample plots before the heavy thinning. Five years after heavy thinning on S.P.-1, current increment of basal area per ha was 89 %, and volume 88 %, compared to S.P.-2. In the following five-year period, current increment of basal area per ha of the same trees on S.P.-1 was 95%, and volume 92%, compared to S.P.-2. Throughout the study period, current increment of basal area and volume of the remaining trees per ha on S.P.-1 was 92% and 90%, compared to S.P.-2., as the consequence, primarily, of the different number of trees which incremented on sample plots. Current increment of diameter, basal area and volume per tree on S.P.-1. during the first five-year period was higher by 21-22%, during the second five-year period it was higher by 26-30%, and in the entire study period, it was higher by was 23-25%, compared to S.P.-2, and it is the consequence, primarily, of the different intensity of increment of the remaining trees on sample plots. In both five-year periods, the trees on S.P.-1 had greater diameter increment compared to the trees on S.P.-2 in all diameter degrees. After 10 years, on S.P.-1, mean diameter of the remaining trees increased by 16.1%, basal area by 34.7%, and volume by 50.8%. During the same period on S.P.-2 mean diameter of the remaining trees increased by 13.2%, basal area by 28.4%, and volume by 40.4%, so it can be concluded that heavy thinning had a favourable effect on the increase of increment of the remaining trees during the study period

Tree of heaven (Ailanthus altissima (Mill.) Swingle): Genetic imprints of geographic origin in Europe

Vytauto Didžiojo universitetasŽemės ūkio akademij

Mapping the patchy legislative landscape of non-native tree species in Europe

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