Characterization and comparison of the wood anatomical traits of plantation grown Quercus acutissima and Quercus variabilis

Oaks are important tree species, providing essential biomaterial for the wood industry. We characterize and compare wood anatomical traits of plantation grown Quercus acutissima Carruth. and Q. variabilis Blume to provide more detailed information to understand xylem radial growth, structure, and function, as well as differences between sapwood and heartwood, to provide data relevant for tree breeding and value-added wood utilization of oak plantations in China. In this study, radial strips were collected at breast height from the main trunk of the two species. Latewood percentage and growth ring width were investigated by X-ray densitometry and a Tree Ring Analysis System, respectively. Vessel and fibre lumen diameter, vessel and fibre wall thickness, vessel density, fibre wall thickness/diameter ratio, tissue proportions, and pit membrane thickness in between vasicentric tracheids were observed with light microscopy and electron microscopy and quantified. There were significant differences in a few wood anatomical traits between the two species: vessel wall thickness and vessel lumen diameter were higher in Q. acutissima than in Q. variabilis, while higher axial parenchyma proportion in sapwood was found in Q. variabilis than in Q. acutissima. More abundant tyloses were found in heartwood than in sapwood of both species. Our work showed the intraspecific and interspecific variation of the two species. Most differences between sapwood and heartwood must be attributed to differences in cambial age during their formation.

Variación de rasgos del xilema secundario de Bulnesia retama (Zygophyllaceae) a lo largo de un gradiente de aridez en el centro-oeste de Argentina

The study of secondary xylem of Bulnesia retama along an aridity gradient allowed finding variations among different xylem cell types that can be used to predict tolerance of this species to aridity. The aim of this work was to carry out an anatomical description of the secondary xylem through cross sections, to analyse the variation of traits considered to be important for survival in arid environments, such as the percentage of vessels, fibres and parenchyma, fibre wall thickness, and wood density. The samples were obtained from primary branches of plants from four locations along an aridity gradient (Médanos Grandes, Bermejo, Marayes and Chepes, San Juan and La Rioja provinces, Argentina). Cross sections were observed with optical microscope and resulting digital images were analysed with ImageJ software. The results indicate that vessels are small, numerous and diagonally distributed, axial parenchyma is apotracheal diffuse. A significant increase in total fibre area and a decrease in parenchyma area with increases in aridity were observed. Total vessel area did not show any changes, while fibre wall thickness increased slightly with aridity. These traits suggest that B. retama has a highly drought-tolerant wood showing phenotypic plasticity along the aridity gradient, also registering a high-density xeromorphic wood.

Wood identification and acoustic analysis of three original Aztec teponaztli musical instruments

Teponaztlis exhibited in Mexico’s Anthropology Museum are the most emblematic items among Aztec musical instruments. The purpose of this research was twofold: to correctly identify the wood used to manufacture three of the most important instruments of their kind and to perform an acoustic analysis to determine relevant acoustic and musical parameters of these instruments. Wood identification consisted in comparing some anatomical features of teponaztlis to those of known species from a wood collection and other sources. Multivariate analysis shows that species are separated by the percentage of uniseriate and partially biseriate rays at one hand and by fibre wall thickness at the other hand. The results show that the genus Dalbergia was used for these instruments, and the analysis suggests proximity of teponaztlis to Dalbergia palo-escrito, and to D. granadillo. The acoustic analysis was based on digital sound recordings of the instruments played with the under-side cavity closed or open. Results show that musical intervals between the two low and high pitch tones of the instruments are from slightly below a major third, to slightly above a fifth. Tones produced with the under-side cavity closed are slightly shorter in duration, and stronger, in comparison when it is open. Playing one of the two tones faintly produces sound from the other, and also from the sides of the instrument, especially with the under-side cavity open. The musical intervals that are observed in these instruments do not correspond exactly to conventional Western tunings.

Anatomical properties of Anthocephalus cadamba (Roxb.) Miq. at five different ages

Anthocephalus cadamba is an important tree species for pulp and paper industry. Anatomical studies were conducted between trees of different age viz., 2, 4, 6, 8 and 10 were selected from different plantation. One plus tree from each age was felled for the study. The transverse discs of 10 cm thickness were collected from three different heights of tree representing base, middle and top positions. Anatomical properties like Fibre Length, Fibre Diameter, Fibre Lumen Width, Fibre Wall Thickness, Flexibility, Slenderness ratio, Runkel ratio, Vessel Length, Vessel Diameter, Vessel Area, Vessel Frequency, Ray Height, Ray Width and Ray Frequency were studied. Present study revealed that the average Runkel ratio of Anthocephalus cadamba was 0.48; hence it is suitable for pulp and paper production. Fibre length at the ages of 6, 8 and 10 were at par. Fibre wall thickness were not significantly different at 2, 4, 6 and 8 age but 10 years of age fibre wall thickness differed significantly from other five different ages. Fibre diameter, fibre lumen width and slenderness were at par for all the five ages. Flexibility was at par in the ages of 2, 4, 6, and 8. Best practice of harvesting Anthocephalus cadamba would be at the age of six. Ray and vessel morphology did not show any specific trend from two to ten years old tree.

Surface and internal micro/ultrastructure of TMP fibres produced during high-intensity refining elucidate the development of pulp and paper properties

Refining during mechanical pulping causes delamination and internal fibrillation (D/IF) of the fibre wall and changes the surface ultrastructure. Fundamental knowledge about these phenomena at the fibre cell wall level helps our understanding of the development of pulp and paper properties, which in turn facilitates the optimization of processes, helping to save energy and improve the characteristics of final products. In the present study, pulps were produced by double-disc (DD) refined thermomechanical processes (DD-TMP) and have been characterized at the fibre cell wall micro/ultrastructural level based on Fernando and Daniel’s method (2010) of Simons’ staining and scanning electron microscopy (SEM). The pulps studied were never-dried Norway spruce DD-TMP from a full-scale mill trial running under different process conditions; a) varying refining intensity, achieved by using a high-intensity turbine segment (HTS) and a standard (Ref) segment from Metso, and b) varying specific energy consumption (SEC). Improved energy efficiency was obtained with HTS segments, giving adequate or better pulp properties with respect to elongation, light scattering, Canadian Standard Freeness (CSF) at a similar tensile index level and lower energy consumption. Energy efficiency was gained through an elevated degree of D/IF and S2 fibrillation with low energy input. Both the SEC and segment designs had a significant impact on elevating the degree of D/IF. Statistical evaluation of fibre development with respect to D/IF gave evidence for improved energy efficiency in HTS refining. Ultrastructural studies on fibre surfaces showed that HTS refining produced better external fibrillation and leads to exposing the secondary S2 wall as fibre outer layer with different ribbon-type S2 fibrillation. Information obtained at the fibre wall level concerning D/IF and surface ultrastructure contribute to the fundamental knowledge about the pulp and handsheet properties and the energy efficiency of TMP processing.

Relation between fibre flexibility and cross-sectional properties

The correlation between the fibre flexibility and cross-sectional area moment of inertia of thermomechanical pulp fibres was investigated. The main effects of refining were found to be internal fibrillation, external fibrillation, and fibre shortening. Internal fibrillation increases fibre flexibility and fibre collapsibility, improving fibre-to-fibre contact in a paper sheet. The raw materials used were pulps produced from six different Norway spruce logs and six different Scots pine logs, chosen in a manner that allowed variation of fibre wall thickness and fibril angle independently. Each wood sample was refined in four stages using a pressurized 12″ Sprout Waldron single disc refiner. Fibre flexibility was assessed by FiberMaster bendability measurements. Fibre bendability was measured on the +48 Bauer McNett fractions of the twelve 2nd, 3rd, and 4th stage thermomechanical pulps (TMP). The fibre cross-sectional samples were imaged using scanning electron microscopy (SEM). An image analysis method to calculate the area moment of inertia of each fibre using numerical integration was developed. Fiber bendability increased with specific energy consumption for both wood species (spruce and pine) from the 2nd refining stage to the fourth refining stage. Spruce had a higher rate of bendability increase than pine upon refining. It was expected that fibres with a low area moment of inertia would result in higher bendability, but no such correlation was found for either spruce or pine. Fibre bendability increased with internal fibrillation, as assessed from Simons staining. These results imply that local damage of the fibre wall such as delaminations, kinks, and compressions was the main effect in increasing the flexibility through refining of TMP.