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Jaworski A., Karczmarski J., Pach M
The aim of this study was to determine relationships between selected properties of juvenile wood and characteristics of the stem and crown of Scots pine. Analyses were conducted in northern Poland on eight mature pine monocultures. Nine trees were selected in each experimental site and their stems were divided into five sections. The centers of the sections were established at a height of 1.3 m from the tree base and at points corresponding to 20, 40, 60 and 80% tree height. Samples were taken from these locations, and these samples were prepared for analyses of basic density, compressive strength along the grain and static bending, as well as the modulus of elasticity during bending. The mean height of the investigated group of trees was 26.0 m with an average diameter breast high of 33.6 cm. The mean crown depth was 7.8 m and crown diameter was 3.6 m, and the mean basic density (Qu) of juvenile pine wood was 416 kg/m3. The average compressive strength along the grain (CS) was determined to be 22.3 MPa, while static bending strength (BS) was 45.8 MPa. The recorded modulus of elasticity (MOE) was 4726 MPa.
Both in general terms and when dividing stems into sections, the wood properties correlated with tree characteristics to various degrees. All indexes were negative indicating that trees of greater dimensions produce juvenile wood of inferior quality. Properties of juvenile wood formed during various periods of tree life were mostly related to diameter breast high and crown depth. They were also correlated with tree height, but only to a limited extent. In contrast, properties of wood from the middle stem sections were significantly correlated with crown diameter.
This paper investigates the slenderness of black locust (Robinia pseudoacacia) trees in relation to the biosocial status of the trees, stand age class, crown parameters and habitat type. The research material was collected on 35 research plots in the Sława Śląska, Sulechów and Głogów forest districts in western Poland and comprises 1058 trees. For each tree, we measured height (h) as well as diameter at breast height (d) and determined its biosocial status (Kraft class), crown length (CL) and relative crown length (rCL). The age class and habitat type were assessed at the plot level. Because the obtained values for slenderness (s=h/d) diverged significantly from the normal distribution, we used Kruskal-Wallis and Mann-Whitney tests to investigate the influence of the above-mentioned parameters on the h/d ratio. Black locust slenderness ranged from 0.31 to 1.95 with an average of 0.91 (standard deviation 0.24). It furthermore differed significantly between Kraft classes (the higher the biosocial status, the lower the slenderness) and age classes (the older the trees, the lower their slenderness). We also found a significant effect of the habitat type (in oligotrophic sites trees formed more slender trunks than in mesotrophic sites) and crown parameters on the h/d ratio (decreasing with increasing crown length and relative crown length). The obtained results suggest that the slenderness of black locust does not differ substantially from native broadleaved trees in Poland.
Nenad Stošić, Stefan Dačić, Marina Ranđelović, Andrijana Jovančić, Ivana Đorđević, Maja Cvetković, Dušan Ilić, Aleksandra Petrović and Dragica Dačić Simonović
Morphological and anatomical characteristics of the tooth are of great importance for clinical dentistry. These aspects of the tooth can be better conceptualized from the perspective of external and internal morphology of dental crowns and roots.
The aim of this study was to determine the average total length of the upper first and second premolars, the average length of crowns, the average length of roots and to determine the most common number of the roots and root canals of these teeth.
We used 41 first and 48 second extracted upper premolars.The length of these teeth was measured by a digital micrometer. The number of roots was determined visually, and each tooth was longitudinally dissected across the vestibular-palatal plane for determining the number of root canals.
The average total length of the upper first premolars was 22.5 mm, the average crown length was 8.8 mm, the mean root length was 13.7 mm. The upper first premolars usually have two roots in 53.7% and two root canals in 82.9%. The average total length of the upper second premolars was 22.5 mm. The average crown length was 8.4 mm and the mean root length was 14.1 mm. The upper second premolars usually have one root in 89.6% and one root canal in 79.2%.
The determined average values of the length of these teeth and the length of their crowns and roots were similar to the values of the same population reported by other authors.
The study presents the results of an analysis of the pine tree growth increments (height increment, dbh increment, basal area increment and volume increment) for a 5-year period. The study involved Scots pine trees of Kraft’s class 1, 2 and 3 (dominant stand) in stands of different age classes (II, III, V) growing in fresh mixed coniferous (BMśw) and fresh coniferous (Bśw) forest habitats. The multivariate analysis of variance was performed to assess the statistical significance of age and dominance of trees within a stand on their increment. The dominance position was classified for each tree using Kraft’s criteria. The following characteristic were also measured: dbh of the trunk in two directions (N-S and W-E), and crown projection area on the basis of the characteristic tree crown points, projected using of a crown projector, characteristic points in tree crowns (7 to 14 on average). The actual height was determined after trees were felled. The following measurements of the single tree growing space were selected and determined: crown projection area - pk (m2), crown diameter - dk (m), Seebach’s growth space number - dk / d1.3, crown projection area to basal area ratio d 2 k / d 2 1.3, crown deflection coefficient dk / h, single tree space ppd = pk·h (m3). We assessed the strength of the relationships between tree growth parameters and tree growth space, crown length, relative crown length and slenderness. Both the age and dominance position of trees within the stand affected the growth increments. The strongest correlation among measured traits was between the 5-year volume increment and decreasing slenderness.
Structural diversity is one of the most interesting phenomena that have been studied by forest ecologists and practitioners. Amongst the different characteristics of forest structure, spatial diversity of trees and their attributes seem to be very important The more spatially structured a population is, the higher its diversity in terms of size and species richness. Because most forests in Europe are managed and were artificially established, they are subjected to conversion processes turning them into more complex systems. The approach presented here aims at elucidating whether natural processes, such as self-thinning, can cause the self-differentiation of spatial structure in artificially planted stands.
Our analyses focused on untended Scots pine and pedunculate oak stands in the juvenile phase of development and were based on spatially explicit structural indices for positioning and size differentiation (diameter, total height and crown length). The obtained results indicate that live trees were dispersed more or less regularly. Unlike the anglebased index, which mostly indicated randomness in tree location, a distance-based index showed clear regularity. We also found that the distribution of tree attributes auto-correlates to tree location as indicated by significantly tower index values compared to values resulting from random reassignment of the examined attributes. This low degree of spatial differentiation is further confirmed by the distribution of indices in differentiation classes. Our results allow us to conclude that, in the case of light demanding species (pine and oak.), natural processes do not increase spatial diversity of the stand, although, both species showed a certain degree of deviation in this respect.
Genetic divergence studies were carried out in clones of Casuarina equisetifolia L. selected from Chidambaram/ Chengalpet (CH/CP) and Tiruchendur (TCR) in Tamil Nadu, India. 33 CH/CP clones and 43 TCR clones were subjected to the analysis separately at 8 years of age. Mahalanobis’ D2 technique was used to study the genetic divergence and the clones were grouped into different clusters using the Tocher’s method. Tree height, diameter at breast height, collar diameter, crown length, cladode length, cladode diameter, number of primary branches, frustum volume and volume index were the characters used for the analysis. Application of Mahalanobis’ D2 statistics and Tocher’s clustering method grouped the CH/CP clones into eleven clusters with cluster strength varying from one (clusters X and XI) to eleven (cluster V) and the TCR clones into seven clusters with cluster strength from one in cluster VII to twelve in cluster VI. Among the various characters, volume index contributed the maximum towards genetic divergence. Based on the inter and intra-cluster distances, male clones CH 3004, CH 0401, CP 0207, CP 3903, CH 2604 and CP 1501 and female clones CH 2703, CH 2803, CP 3703, CP 0301 and CH 3002 are recommended for further breeding programmes from the CH/CP group. From the TCR group of clones, TCR 110202, TCR 090201 and TCR 030101 (male) and female clones, TCR 040204, TCR 120102, TCR 080201, TCR 120203 and TCR 090102 are recommended. The results on genetic divergence have got an immediate application in the establishment of clonal seed orchards. Information on genetic distance between genotypes helps in developing planting design, such that it can facilitate equal opportunity for hybridization among the genotypes and obtaining quality seeds with high vigour.
Modelovanie dopadov prirodzenej a umelej obnovy na genetickú štruktúru: 2. nezmiešaný jeľový porast
V príspevku je hodnotená variabilita plodnosti materských stromov a vplyv vybraných obnovných rubov v nezmiešanom poraste jedle bielej. V tomto 120-ročnom, obnovou rozpracovanom poraste na Starých Horách bola vo výške 850 m n. m. založená výskumná plocha so 165 stromami. Pozícia jednotlivých stromov bola zameraná, zistená bola ich výška, prsná hrúbka, veľkosť a projekcia koruny, početnosť šišiek v štyroch po sebe nasledujúcich rokoch a samčích strobilov v jednom roku. Pomocou izoenzýmových genetických markérov boli v 17 lokusoch určené aj genotypy všetkých stromov.
Pomocou programu Eco-Gene (Degen & Gregorius & Scholz 1996) boli postupne testované: dvojfázový okrajový, skupinový, skupinovitý clonný, jednotlivo a skupinovo výberný rub. Na ich vyhodnotenie boli použité 3 kritériá: minimálna tvorba priestorovej genetickej štruktúry v potomstve, minimálna diferenciácia potomstva od materskému porastu a zachovanie genetickej variability v potomstve. Najviac týmto kritériám vyhovoval skupinovitý clonný rub. Ostatné obnovné zásahy boli menej vhodné a ich postavenie bolo viac-menej rovnocenné.