Kronologija jelke (Abies alba Mill.) za območje Pohorja

Dendrochronological investigations were made in silver fir (Abies alba Mill.) from Lovrenc, Pohorje, in the NE Slovenia. Tree ring analyses were made in discs of 25 healthy, adult, dominant or co-dominant silver firs and in cores from roof construction of two older rustic buildings from the same region using a LINTAB measuring device nad a TSAP/X of F. Rinn. We constructed the chronology of trees spanning the period of 1785-1996. The chronology of the old house is spanning the period of 1713-1852 and the chronology of barn 1745-1887. It was shown that the last considerable reconstruction of the house roof took place after the end of the growing period of 1952. The dating of the cores containining the outer ring 1887 confirmed the dating based on the carved inscription "1888". The three chronologies were joined into 284 years long silver fir chronology for Pohorje spanning the period of 1713-1996. It was compared with the Slovene silver fir chronology of the Dinaric region. Despite distance and great differences between the two regions there was shown a statistically confirmed similarity of two chronologies with tBP=9.8, GLK=71% and CDI=398. The chronologies have 21 common negative, 21 positive signature years and one common signature interval. Based on this the constructed chronology may be considered as representative for the whole Pohorje. The two chronologies are expected to be a good base to construct a regional Slovene Silver-fir chronology for dating in whole Slovenia. Two Slovene chronologies were compared with the following European silver fir chronologies: South German, stand 1993 (Becker and Siebenlist 1970Spurk and Friedrich , pers. com.), Bavarian Forest - Germany (Eckstein, Sass 1988), Abetone - Italy (Schweingruber, ITRDB), Bannwald - Switzerland (Schweingruber, ITRDB). Both Slovene chronologies proved to be statistically similar with the two German and the Italian silver fir chronology, but showed no similarity with the Swiss one. The Pohorje chronology correlates better with both German ones and the Dinaric chronology correlates better with the Italian one

Silver fir Abies alba Mill. wood as raw material and tree tissue

Predstavljen je pregled zgradbe, lastnosti in rabe lesa jelke (Abies alba Mill.), ki ima neobarvano jedrovino, srednjo gostoto, relativno dobre mehanske lastnosti in je uporaben za številne namene. Vrednost in uporabnost lesa zmanjšujejo predvsem slaba odpornost proti različnim škodljivcem ter pojav mokrega srca in kolesivosti. Lastnosti lesa in uporaba lesa jelke so podobne kot pri smreki (Picea abies Karst.). Jelovina ima prednost predvsem tam, kjer smola ni zaželena, kjer je zaželena odpornost na kisline in baze, ter za vodne konstrukcije. Na primeru dendrokronološko datiranega lesa iz arheoloških in zgodovinskih objektov v Sloveniji smo ugotovili, da so jelovino v preteklosti uporabljali pogosteje kot smrekovino. Dokaz za to so številne do 500 let stare konstrukcije in ostrešja zgodovinskih stavb. Na celičnem nivoju je les jelke sestavljen predvsem iz traheid in parenhimskih celic trakov. V zadnjih letih so bile v Sloveniji opravljene podrobnejše raziskave nastajanja lesa pri jelki, ki so pomembne za fiziologijo drevja in razumevanje lastnosti lesa kot materiala. Opravljenih je bilo tudi več raziskav sekundarnega floema, ki je ključnega pomena za preživetje dreves. Podajamo pregled in glavne ugotovitve teh raziskav.We present the structure, properties and use of European silver fir (Abies alba Mill.) wood, which is known for its uncoloured heartwood, medium density,relatively good mechanical properties and the fact that it can be used for a great variety of products. The value and usefulness of fir wood are reduced due to low resistance against decay and deterioration, and frequent occurrence of wet heart, and ring shakes. The properties of fir wood are comparable to those of Norway spruce (Picea abies Karst.). Fir is favoured where resin is not desired, where durability against acids and bases is important, and for water constructions. We present some examples of wooden constructions in archaeological or historical objects in Slovenia. The dendrochronologically dated wood was up to 500 years old. In the past centuries, fir was used more frequently than Norway spruce. On the cellular level, the wood of fir consists of tracheids and parenchyma cells. In Slovenia, several studies of wood formation have been conducted e in recent years, which are important for a better understanding of the physiology of trees and quality of wood as material. Secondary phloem, which is particularly important for the survival of trees, has been studied as well. We review some main results of such studies

Application of transmission electron microscopy and UV-microspectrophotometry for detection of lignin in cell wall of conifers

Kalijev permanganat je kot reagent v transmisijski elektronski mikroskopiji (TEM) zelo uporaben za ugotavljanje prisotnosti lignina v različnih morfoloških področjih lesa. Ker je metoda le kvalitativna, je priporočljivo rezultate, ugotovljene s TEM, potrditi še s kakšno drugo kvantitativno metodo,kot je npr. UV-mikrospektrofotometrija (UMSP). Metoda UMSP je zelo primerna za določanje vsebnosti lignina in njegove porazdelitve v lesnem tkivu. V članku je predstavljena metodologija in uporabnost TEM ter UMSP pri proučevanju porazdelitve lignina v celični steni.Potassium permanganate represents a useful tool in transmission electron microscopy (TEM) for the localization of lignin in various morphological regions of wood. Since this method only provides qualitative estimation, another quantitative method is recommended to verify the results obtained by TEM, such as UV-microspectrophotometry (UMSP). The UMSP method was found to besuited for the determination of lignin content and its distribution in woodytissue. The present paper provides a methodical description and presents the applicability of TEM and UMSP for studies in the topochemistry of lignin distribution within cell walls

Dendrochronological investigations in Založnica - the latest known Eneolithic pile dwelling at Ljubljansko barje

Investigations in wood and archaeological artefacts collected during rescue excavations in the drainage ditches on the location of copper-age, i. e. Eneolithic pile dwelling Založnica at Ljubljansko barje (Ljubljana Moors, Slovenia) are presented. 35% of 1315 samples were dendrochronologically investigated. We constructed three tree-ring chronologies, two of ash-wood (Fraxinus sp.) and one of oak (Quercus sp.), and reconstructed the building activities that occurred in the period of 90 years. We found out that the activities in Založnica coincided with those in another pile dwelling Parte, which existed in the same period and was located 10 km away from Založnica. Based on radiocarbon dating, the activities in Založnica ended in the 25th century BC. The last 40 years of the settlement delineate the youngest Copper Age settlement at Ljubljansko barje and in Slovenia. We describe how the dated wood and its relation to other archaeological artefacts helped us to place Zloznica in the Somogyvár-Vinkovci culture. This cultural classification constitutes a new interpretation of settlement activities before the Bronze Age began at Ljubljansko barje, in Slovenia in general, and in the neighbouring countries

Density and mechanical properties of oak sapwood versus heartwood in three different oak species

The aim of this study was to investigate the main mechanical properties of sapwood and heartwood in white and red oaks. Samples of wood were taken from 26 oak beams prepared to be used for railway sleepers, of which 62% were from white oak (either Quercus petraea or Q. robur) and 38% from red oak group, represented by Q. cerris. For both oak groups, the following parameters were determined: the density, bending strength, modulus of elasticity (MOE), compression strength and Brinell hardness of sapwood and heartwood. Multiple analyses were done to compare the properties of sapwood and heartwood, as well as the properties of white vs. red oaks. The results revealed no significant differences between sapwood and heartwood properties but statistically significant differences were found between the properties of white and red oaks. The research results contradict the common opinion of users that the mechanical properties of sapwood are inferior to those of heartwood. Investigations revealed that Q. cerris had even better mechanical properties than Q. robur or Q. petraea, which also contradicts the common opinion that its mechanical properties are inferior to those of white oaks. The results help to understand better wood variability for optimal selection of timber for constructions

Secondary Cell Wall Formation and Lignification of Latewood Tracheids near Cambium in Silver Fir (Abies alba) during Dormant Period

The aim of this study was to investigate the process of differentiation of terminal latewood tracheids near the cambium in silver firs (Abies alba) during dormant period. Samples of wood and cambium were taken from 10 apparently healthy mature trees in the middle of October, November and March. According to light microscopy, transmission electron microscopy and UV–microspectrophotometry, cambial cell-divisional activity was completed in all investigated trees in October, whereas process of differentiation was still ongoing in the youngest tracheids close to the cambium in trees with broader annual xylem growth rings. Layer S3 of the secondary cell wall and warty layer were not formed and inner parts of S2 layer of secondary cell wall were not yet lignified. Only four weeks later, in November, the cell wall formation and the lignification of terminal latewood tracheids close to the cambium were completed in all trees. No alterations were observed at the ultrastructural level between November and March samples. The cambial cell-divisional activity and also differentiation ended later in trees with broader annual xylem growth rings. However, differentiation of terminal latewood tracheids in all investigated trees was completed before winter

Relation between xylem and phloem increment in Silver fir (Abies alba Mill.)

Pri 10 zdravih jelkah (Abies alba) smo raziskali anatomsko zgradbo floemskih branik (FB) glede na njihovo širino, razmerje med številom slojev celic v FB in v ksilemskih branikah (KB) iste sezone, razlike v številu slojev celic v FBin KB po obodu posameznega drevesa ter zvezo med širino FB in KB, nastalih vistem letu, ter širino dormantne kambijeve cone (KC). Intaktne vzorce tkiv zaraziskave smo vzeli iz živih dreves v letih 2001 in 2002 ter pripravili preparate prečnih prerezov za svetlobno mikroskopijo. Ugotovili smo zvezo med širino in anatomsko zgradbo FB. Pri ožjih FB je prevladoval rani floem, pri širših pa kasni. Pri širših FB se je v kasnem floemu lahko pojavil dodatni pasaksialnega parenhima. KB so bile 2- do 21-krat širše od FB. Širina KB je poobodu posameznega drevesa bolj variirala kot širina FB. Širina dormantne KC je bila v pozitivni zvezi s širino FB in KB.In 10 silver firs (Abies alba), the following was investigated: anatomical structure of phloem growth rings (FB) in relation to their width, ratio between number of cell-layers in FB and in xylem growth rings (KB), variation in number of cell layers in FB and KB around the stem circumference, relation between widths of FB and KB formed in the same year, and the width of dormant cambial zone (KC). Samples of intact tissues were taken from living trees in 2001 and 2002, and permanent cross-sections for light microscopy prepared. We observed the relationship between width and anatomical structure of the FB. Narrower FB contained more early phloem, whereas wider FB contained more late phloem cells. Wider FB sometimes contained an additional band of axial parenchyma. The KB were 2 to 21 times wider than the FB. The widths of KB varied around the stem circumference more than the widths of FB. The widths ofdormant KC were positively correlated to the widths of FB and KB