Wood analyses helped to determine the location and approximate construction period of the Roman bridge over the Drava River in ancient Poetovio (Ptuj, Slovenia)

We present the results of a dendrochronological study and radiocarbon dating of the wooden piles of the bridge over the Drava River in Ptuj. The piles, together with stone elements (a fragment of an imperial building inscription and parts of the architectural decoration) were retrieved from the riverbed in 1913 and are now in the Regional Museum Ptuj - Ormož. Using dendrochronology, radiocarbon dating of carefully selected annual rings in the wood and calibration with the wiggle-matching method, the date of the last (outermost) annual ring on the pile was determined to be 161 ± 27 cal AD (1σ) or 160 ± 32 cal AD (2σ). Since the pile contained no sapwood, the dating approximately agrees with the date of the building inscription on the stone slab, which attributes the commission for the reconstruction or construction of the bridge to Emperor Hadrian in the last years of his reign (117-138 AD). The dating of the wood has thus confirmed that the remains examined do indeed belong to a Roman bridge, probably built or renovated during the reconstruction of the road network in the area of the colony of Poetovio under Hadrian or one of his successors.

Signature Modes of Old and New Violins with Symmetric Anatomical Wood Structure

The paper aims to investigate old and new violins from the perspective of the correlation between the anatomical structure of spruce and maple wood, and the dynamic response of violins. Thus, in the first stage, for each violin, the characteristics of the annual rings were measured on the entire width of the top plate, determining the degree of symmetry of the face with respect to the longitudinal axis of the violin body. Then, each violin was dynamically tested with the impact hammer, determining its own frequency spectrum, mainly the so-called “signature” mode and quality factors. The most important findings consist of identification of the first five modes for old violins, (known as provenance), current new violins, and violins whose origin is unknown, but which could correlate with anatomical, constructive and dynamic characteristics, in order to be able establish origins, and also the measurement of anatomical features of top and back plates in the violins’ construction.

Relationship of tracheid length, annual ring width, and wood density in Scots pine (Pinus sylvestris L.) trees from different social classes of tree position in the stand

This study investigated the relationship between the length of the tracheids, the width of annual rings, and the wood density of Scots pine (Pinus sylvestris L.) obtained from the dominant, intermediate, and suppressed classes of a 60-year-old stand. Measurement of tracheid length was performed on the material macerated from the following annual rings: 3, 6, 9, 12, 15, and thence every 5 annual rings. Basic density was determined on samples that included five annual rings from the core to bark. Tree position in the stand had a significant impact on the examined properties of wood. In a given biosocial class, tracheid length decreased as the width of annual rings increased. As the biosocial position of a tree in the stand improved, the length of the tracheids increased, and wood density decreased. In wood of the same density range, the increment in tracheid length was the greatest in wood of dominant trees and the lowest in wood of suppressed trees.

EFFECT OF IMISSION TO XYLEM ANATOMY OF NORWAY SPRUCE

The aim of this work was to analyse the relationship between anatomical parameters of spruce tracheidsand climatic factors and air pollution load, in the period before, during and after the maximum air pollution load. In this study we used the method of dividing annual rings into a number of equally wide sectors, for which the average values of the tracheid dimensions, i.e., the lumen area and cell wall width, were determined. This method was compared to the classic approach, which works with the average values of parameters for the entire annual ring, or for earlywood and latewood. The study showed that the trees responded to the increased concentration of pollutants by reducing the widths of the annual rings and the values of the anatomical parameters. The higher resolution of data gives us a better insight on the influence of abiotic factors to the wood structure. The ratio of cell wall thicknesses ofearlywood to latewood was also shown asa good indicator of stress.

BIOSOCIAL DIVERSITY OF SCOTS PINE (PINUS SYLVESTRIS L.) IN A TREE STAND IN RELATION TO CHOSEN HYDRAULIC CONDUCTIVITY INDICATORS OF THE STEM

The research focused in determining the lignification indicator of fresh needled springs and the mass of fresh needles in reference to the lignin content in tracheid walls of peripheral area of the stem (MFT/LC and MFN/LC) of Scots pine differentiated as far as its biosocial position within the community expressed by Kraft’s classification. The material for the analysis came from mature pine stands growing on North European Plain, on the territory of Poland. Chemical and structural analyses of wood encompassed the area of mature sapwood, i.e. thickness of the last 10 annual rings located at 1.3 m (DBH). It seems that the noticed differences values of both indicators (MFT/LC and MFN/LC) in pines belonging to the first three Kraft’s biological classes are connected with physiological, physical and structural conditionings of water transport with minerals in xylem and are closely connected with competition for sunlight, water, nutrients and living space.

Multi-stage parallel model in determining the quality of structural timber by the penetration method

Multi-stage parallel model in determining the quality of structural timber by the penetration method. Various devices are used in situ to diagnose the quality of structural timber. A semi-destructive method is used for the approximate determination of wood density. The Pilodyn 6J uses a depth of cut that correlates with wood density. The experiments were performed on spruce wood (Picea excelsa, Karst. L.). Boards 40 × 200 × 2500 mm3, were tested, n = 5 pcs. The density of wood was determined by the gravimetric method according to EN 408 (2013). The penetration depth (hp), number and width of annual rings (RoG) were determined on the boards. Based on the density of the wood, the quality of the structural timber was specified by strength classes according to EN 338 (2016). The dependences between the measured characteristics were expressed in a model with a multi-stage parallel scale (penetration depth ~ number of annual rings  rate of growth  strength class and density wood). It is possible to predict visual strength class of board and indicative density of wood (EN 338) by the proposed model in situ. Methods of model are easy to use, reliable and economically undemanding.