Late Wood Research Articles

Determination and Analysis of Endogenous Hormones and Cell Wall Composition between the Straight and Twisted Trunk Types of Pinus yunnanensis Franch

Pinus yunnanensis Franch., one of the pioneer species of wild mountain afforestation in southwest China, plays an essential role in the economy, society and environment of Yunnan Province. Nonetheless, P. yunnanensis’ trunk twisting and bending phenomenon has become more common, which significantly restricts its use and economic benefits. In order to clarify the compositional differences between the straight and twisted trunk types of P. yunnanensis and to investigate the reasons for the formation of twisted stems, the present study was carried out to dissect the macroscopic and microscopic structure of the straight and twisted trunk types of P. yunnanensis, to determine the content of cell wall components (lignin, cellulose, hemicellulose), determine the content of endogenous hormones, and the expression validation of phytohormone-related differential genes (GA2OX, COI1, COI2) and cell wall-related genes (XTH16, TCH4). The results showed that the annual rings of twisted trunk types were unevenly distributed, eccentric growth, insignificant decomposition of early and late wood, rounding and widening of the tracheid cells, thickening of the cell wall, and reduction of the cavity diameter; the lignin and hemicellulose contents of twisted trunk types were higher; in twisted trunk types, the contents of gibberellin (GA) and jasmonic acid (JA) increased, and the content of auxin (IAA) was reduced; the GA2OX were significantly down-regulated in twisted trunk types, and the expressions of the genes associated with the cell wall, COI1, COI2, TCH4 and XTH16, were significantly up-regulated. In conclusion, the present study found that the uneven distribution of endogenous hormones may be an important factor leading to the formation of twisted trunk type of P. yunnanensis, which adds new discoveries to reveal the mechanism of the genesis of different trunk types in plants, and provides a theoretical basis for the genetic improvement of forest trees.

Особенности роста и структуры древесины сосны на вырубке и под пологом древостоя в условиях Республики Карелии

The intraspecific variability of the anatomical and hydraulic characteristics of xylem in the undergrowth in Scots pine (Pinus sylvestris L.) has been assessed during natural regeneration in the felling areas and under the canopy of a middle taiga blueberry pine forest in the conditions of the European North (Republic of Karelia). The influence of habitat conditions on the formation of structural elements of wood cells has been revealed. In felling areas under conditions of higher illumination, air and soil temperatures, the transition of pine undergrowth to the category of large with a height of more than 1.5 m occurs at the age of 6 years, whereas under the canopy of a mature stand the undergrowth reaches this category no earlier than 15 years. At the same time, in the 1st decade of growth under felling conditions, the growth of pine in diameter has been 4 times higher than that of pine under the canopy of a mature stand due to the formation of a larger number of rows of tracheids in the early and late zones. In addition, the pine undergrowth in the felling area has the highest potential hydraulic conductivity of the xylem, and, on the contrary, the lowest specific density of tracheids, the basic wood density and late wood content relative to the pine undergrowth under the canopy of the stand. The latter exhibited a significant decrease in the structural and functional characteristics of wood, with the exception of the thickness of the cell membranes of late tracheids. In the interanual dynamics, more stringent linear regression dependencies between the indices of early and late tracheids have been observed in pine undergrowth under the forest canopy. The results obtained indicate a greater correspondence of the environmental conditions in the felling area to the optimum for the growth and formation of wood of young pine trees relative to the conditions under the canopy of a mature blueberry pine forest. Inhibition of the growth activity of undergrowth under the canopy occurs due to high intraspecific competition from the dominant pine stand for light, moisture and soil nutrition.

Estimation of the earlywood and latewood ratio with different particle size of dry and wet milled Japanese cedar wood flour by using hyperspectral imaging

Mechanical properties of wood–plastic composites are influenced by a particle size and surface morphology of wood flour. Generally various sizes of wood flour are produced from single solid wood even if the single process is used. If the different particle size of wood flour is produced from different wood tissue such as earlywood (EW) and latewood (LW), not only particle size but also density and chemical composition of wood flour might influence the mechanical property of final products. This study aims to investigate the relationship between particle size and their origin; EW and LW. EW and LW were separately milled to produce the EW and LW flour by dry and wet milling. Hyperspectral images ranging 400–1000 nm for each wood flour were used as training data. Discriminant model of EW and LW flour developed by PLS-DA showed over 0.77 of accuracy. Then the EW and LW were dry and wet milled together and screened by three different sieve openings to obtain different particle size wood flour. Discriminant model was applied for the hyperspectral images of each size of wood flour to estimate the EW and LW ratio. The result showed that increasing sieve opening resulted in the increasing ratio of LW for dry milled wood flours. The results suggest that the EW was easily pulverized than LW.

New perspectives on radial profiles of specific gravity in North American conifers

North American conifers exhibit three radial specific gravity (SG) patterns (Type 1, 2, and 3), which balance hydraulic and mechanical requirements. Type 1 and 2 patterns (Pinaceae) have low SG and high microfibril angle (MFA) corewood ensuring compliance, whereas in outerwood high SG/low MFA provide stiffness and strength resisting bending. Hydraulically, corewood, especially in Type 2 species, is resistant to embolism, whereas outerwood has higher specific conductivity. Cupressaceae (Type 3) have hydraulically very efficient, low SG outerwood, facilitating rapid growth. Corewood is flexible, whereas outerwood is mechanically weak and compensated for by more conical stems and durable heartwood (which prevents Brazier buckling). Radially earlywood (EW) decreases, and latewood (LW) increases for all types, whereas %latewood (%LW) increases (Type 1), decreases, then increases (Type 2) and decreases (Type 3). Ring SG increases when increasing LW SG and %LW are sufficient to counteract decreasing EW SG. Shade tolerance, crown recession, hormone gradients, and environmental variation affect patterns. Auxin concentration decreases with increasing distance from juvenile foliage slowing cell division, concomitantly gibberellin concentration (lignification) and carbohydrates (cell wall thickening) increase, producing higher %LW. Across a species range regions receiving relatively high summer rainfall have trees with higher %LW (by ring).

Comparative Studies on Tensile Mechanical Properties of Water-Saturated Earlywood and Latewood within the Same Growth Ring from Masson Pine

The tensile mechanical behavior of water-saturated earlywood (EW) and latewood (LW) within the same growth ring of Masson pine (Pinus massoniana) was investigated in the hydrothermal environment and discussed with respect to the density and microfibril angle (MFA) of the wood specimens. The tensile modulus, tensile strength, and strain at failure of EW and LW in the longitudinal (L) and tangential (T) directions were determined at different temperature levels ranging from 30 °C to 80 °C. Major differences in the tensile mechanical properties were found between EW and LW in the L and T directions. Compared to LW, EW showed a smaller density and a larger MFA, resulting in a lower tensile modulus, lower tensile strength, and higher strain at failure. Compared to the L specimens, the T specimens showed lower tensile modulus, lower tensile strength, and higher strain at failure. As the hygrothermal temperature increased, the MFAs, tensile modulus, and tensile strength of EW and LW specimens decreased, except for the MFAs of LW, while the strain at failure of the specimens showed the opposite trend. Variations in the tensile mechanical behavior between EW and LW were mainly influenced by the density and MFA of the specimens, and are closely associated with the hydrothermal softening properties of wood. These findings contribute to a further understanding of the structural–mechanical relationships of Masson pine wood at the cell wall level, and provide a scientific basis for the better utilization of plantation softwood in the hydrothermal environment.

Research on the Compression Performance and Damage Mechanism of Larix Wood With Smooth Grain

In order to investigate the compression performance and damage mechanism of fallen wood in the down-grain direction, northeast larix was taken as the research object. Through the monotonic compression test of 12 specimens, the deformation characteristics, damage mode, and stress-strain curve properties of larix wood under compression in the direction of the smooth grain were analyzed; scanning electron microscope technology was used to analyze the damage and fracture characteristics of wood fibers from the microscopic point of view to further reveal the damage mechanism of wood monotonic compression. The results showed that larix wood compressed in the paragons produced three damage modes of end collapse, shear damage and paragons splitting after the peak load, and the shear damage usually occurred at the junction of the early and late wood tubular cells due to the difference between the early and late wood tubular cells. On this basis, an isomorphic model was established to describe the compression of larix wood in the smooth grain.

The Effect of Rays on the Mechanical Behaviour of Beech and Birch at Different Moisture and Temperature Conditions Perpendicular to the Grain

The plastic deformation of wood perpendicular to the grain is gaining increasing importance due to advancements in forming technologies and the densification of wood. This study investigates how two hardwood species, i.e., beech (Fagus sylvatica) and birch (Betula pendula), respond to compression in the radial direction and examines the structural changes they undergo during both elastic and plastic deformation. Stress–strain curves at different moisture contents (dry to wet) and temperature conditions (20 to 140 °C) were recorded. In-situ observations at high moisture content and temperatures by means of different microscopic techniques are practically unfeasible. Therefore, the specimens were analysed ex-situ microscopically after the test. In addition to the compression of transversely oriented fibres and vessels, special attention was paid to the deformation behaviour of the wood rays. The results suggest that the wood ray cells carry a relatively higher proportion of the load in the radial loading direction than the surrounding vessels and fibres. This observation is supported by the higher percentage of deformed vessels, seen in the microscopy, in areas where the rays developed kinks, usually in the early wood of beech and anywhere in the cross-section of birch. The weaving of rays around big vessels introduced shear strains under compressive stresses at the kinked rays’ area. Thus, shear deformation is more evident in early wood than in late wood regions of wood. However, when the wood was tested at elevated moistures and temperatures, the material demonstrated a ductile response, namely the absence of localised shear deformations. Notably, wet beech and birch specimens heated to 100 °C and above exhibited pronounced thickness recovery and there was slightly irreversible buckling of rays and vessel deformations. Therefore, under such conditions, wood behaves like a “sponge” and is expected to be successfully processed without introducing clear damage to the material. This characteristic holds promise for replication in the development of bio-based energy-absorbing materials.

Исследование структуры и механических свойств годичных колец древесины дуба черешчатого (Quercus robur) методами наноиндентирования и скретч-теста

Optical methods and optical properties are usually used to research the structure of wood and its ring structure. However, these properties are not directly related to its mechanical and other physical characteristics. To study them, methods of x-ray densitometry, synchrotron radiation, nuclear magnetic resonance, etc., which are not very common in wood science, are used. These methods are quite labor-intensive and require expensive equipment. In this regard, there is a need to develop simple and convenient means and methods for studying the micromechanical properties of wood. The main goal of the work is to develop such an approach using nanoindentation and digital scratching of a cross section of wood and to identify its potential in the further development of dendrochronology and related disciplines. Using the NI method, radial dependences of hardness H and Young's modulus E were obtained for eleven consecutive annual pedunculate oak (Quercus robur L.) wood rings for 3 different loads Pmax = 2, 100 and 500 mN. The values of H in the range from 70 to 340 MPa and Young's modulus E in the range from 2 to 10 GPa were determined for the corresponding loads and early (EW) and late wood (LW). Using the scratch test method, profiles of the normal force Fn and the corresponding hardness HS (in the range from 53 to 225 MPa) were obtained for the period 2007-2020. According to both methods, the widths of annual rings were determined; the discrepancy between the values and the optical method was < 3 %.

Лесоводственная эффективность проведения несплошной лесозаготовки древесины в сосняках после гидротехнической мелиорации в Сокольском районе Вологодской области

In the Sokolsky district of the Vologda region of Russian Federation, the influence of continuous harvesting of
 wood in drained pine forests on the taxation and macrostructural parameters of common pine trees (Pinus sylvestris L.)
 was determined. The objects of the study are represented by pine forests: the main species is Scots pine (P. sylvestris L.)
 with an admixture of common spruce (Picea abies (L.) H. KARST.) and birch (Betula pendula Roth). The drained forest
 objects were selected after the continuous harvesting of wood and a control stand (without logging), temporary test areas
 (runway) were delimited. Drainage measures in experimental forests were carried out in 1972. Continuous logging was
 carried out in 2005 when skidding technological drags were attached to the main corridor at an angle of 45 degrees. The
 distribution of the number of P. sylvestris L. trees by thickness steps within the boundaries of the runway in 83% (p <
 0.05) of cases tends to normal. Average periodical growth of late wood P. sylvestris L. on the runway after drainage
 increased in the channel position by 30 % (tfact ≥ tst; 4.51 > 2.70; p < 0.01), and after intermittent logging increased by
 19 % (tfact ≥ tst; 1.99 > 1.71; p < 0.1). Carrying out continuous complex harvesting of wood in drained pine forests has a
 positive effect on increasing the stock (by 38%), while in stands without logging – by 28 %.

Comparison of the Viscoelastic Properties and Plasticity of Early and Late Wood of Pine and Spruce by Continuous Stiffness Measurement during Nanoindentation

Comparison of the Viscoelastic Properties and Plasticity of Early and Late Wood of Pine and Spruce by Continuous Stiffness Measurement during Nanoindentation

Features of the formation of early and late larch wood in the conditions of the Voronezh region

Features of the formation of early and late larch wood in the conditions of the Voronezh region

METHODOLOGY FOR ASSESSING THE PATHOLOGICAL IMPACT OF DISEASES AND FOREST PESTS ON THE SANITARY CONDITION OF FORESTS IN THE CONDITIONS OF FORESTRY BLANCHES OF THE CENTRAL INTERREGIONAL FORESTRY AND HUNTING MENEGMENT AND NATURE PROTECTION RESEARCH DEPARTMENT OF THE POLISSKY NATURE RESERVE

METHODOLOGY FOR ASSESSING THE PATHOLOGICAL IMPACT OF DISEASES AND FOREST PESTS ON THE SANITARY CONDITION OF FORESTS IN THE CONDITIONS OF FORESTRY BLANCHES OF THE CENTRAL INTERREGIONAL FORESTRY AND HUNTING MENEGMENT AND NATURE PROTECTION RESEARCH DEPARTMENT OF THE POLISSKY NATURE RESERVE

Fertilisation with potato starch wastewater effect on the growth of Scots pine (Pinus sylvestris L.) forest in Poland

Fertilisation is often used to increase plant productivity in agriculture but has also been used in forestry. In our study, Scots pine forest growing in a nitrogen-poor environment was fertilised with NPK post-production wastewater from a potato starch factory. Our research aimed to investigate the dependence of tree growth on different NPK concentrations. Cell characteristics such as cell wall thickness (CWT), lumen diameter (LD) and tree-ring features such as ring width (RW), total number of cells in annual growth (nTotal), earlywood (EW) and latewood (LW) were investigated. Twenty-six years of regular fertilisation of the forest with different doses of wastewater rich in NPK elements have affected the anatomical structure of Scots pine trees. It is presumed that the reduction in CWT and LD on the fertilised site was due to deficiencies in plant water conductivity, which may have occurred due to physiological drought. The influence of nitrogen on unfertilised site from the wastewater area could contribute to the CWT thickening. The results confirm that the use of NPK in excessive doses is detrimental to trees' conductive system.

INFLUENCE OF ANNUAL GROWTH RING STRUCTURE REGULARITIES AND NATURAL DEFECTS ON PHYSICAL AND MECHANICAL PROPERTIES OF CARPATHIAN SPRUCE

In the process of technical inspection of buildings and structures constructed with the use of both solid logs and Carpathian spruce lumber massively observed processes of deplanation of the wall fence, exit from functional state of constructive elements of inter-storey floors and rafter systems. During inspection calculations of existing construction elements, which are in exploitation for all types of stress-deformed state, there are often questions to the accepted constructive solutions of cross-sections and nodal joints of building structures made of solid wood. This fact can only be due to the discrepancy between the strength and deformation properties of Carpathian spruce and the declared characteristics in normative documents. The presence of natural defects and structural features of the Carpathian spruce structure indicate that the unequal physical and mechanical properties of the two coniferous species that grow in the northern latitudes and the Carpathian region of Ukraine are not entirely true. The distribution of the ratio of latewood to earlywood has a direct influence on the physical and mechanical properties of wood. This fact is caused by rather cellular structure of wood with large annual growth of early and late wood. Such characteristics can have both positive and negative effects on the properties of Carpathian spruce as a building material. This type of wood with a high degree of natural moisture content and cellular structure requires a special pre-drying procedure for the production of building structures. To establish the factual physic-mechanical properties of Carpathian spruce, the current normative documents were analysed and the existing scientific research on this issue was studied. In the process of conducting a comparative analysis of the results of comprehensive studies of standard samples of Carpathian spruce for compression along the fibres and control samples made from the base species - pine, the fact of partial inconsistency of physical and mechanical parameters of the two varieties of conifers was established. In general view, recommendations are made for changes to the current norms for the construction of solid timber structures. Keywords: : physic-mechanical properties, bulk weight, wood defects, temporary resistance.

A unique Late Cretaceous fossil wood assemblage from Chilean Patagonia provides clues to a high‐latitude continental environment

AbstractFossil plants, including large trunks, stems, some branches, and twigs, were collected from the Maastrichtian (68.9 Ma), upper Dorotea Formation in the Magallanes–Austral Basin, 16 km north of the Cerro Guido–Las Chinas complex in the southern Chilean Magallanes region. These fossil trunks range from 0.2 to 2.2 m in length. Petrographic slides were made in three sections (transverse, radial and tangential) and analysed under a light microscope to study the permineralized fossils. The woods and stems belong to Austroginkgoxylon gen. et sp. nov., Agathoxylon antarcticum, Podocarpoxylon paradoxi sp. nov., Podocarpoxylon mazzonii, Palmoxylon subantarcticae and Notomalvaceoxylon magallanense gen. et sp. nov. The growth rings of gymnosperms and anatomical characters of angiosperms were analysed to obtain palaeoecological data. Interactions between gymnosperm roots growing into the secondary xylem of an angiosperm (nurse logs) are recorded. The data obtained from the fossil woods suggest warm and humid conditions in this southern South American locality during the Late Cretaceous, providing a unique opportunity to study continental environments at high southern latitudes, which are poorly represented on a global scale.

A late Eocene wood assemblage from the Crooked River Basin, Oregon, USA

A late Eocene wood assemblage from the Crooked River Basin, Oregon, USA

Fossil Wood Analyses: Several Examples from Five Case Studies in the Area of Central and NW Bohemia, Czech Republic.

In the area of the Central and NW Bohemia, Czech Republic, the fossil wood is quite abundant, found in different states of preservation and present from Paleozoic (Pennsylvanian), through Mesozoic (Upper Cretaceous), to Cenozoic (upper Eocene to lower Miocene). So, this small area is ideal to demonstrate various aspects of the fossil wood analyses, including anatomy (unifacial vs. bifacial cambium, formation of tyloses and its significance, early vs. late wood, unambiguity of scientific terminology, stem vs. root wood), taphonomy (completeness of fossil record, influence of environment on mode of preservation, influence of preservation on wood anatomy and preservation potential, discrepancy between the record of wood and other organs), systematics (stem vs. crown group, wide concept of fossil wood genera, "mosaic" species, wood of extinct plants), and palaeoclimatic reconstruction (definition of "wood type," subjective vs. objective methods). The majority of the studied woods were thin-sectioned following the standard techniques and observed with a compound light microscope.

RADIOCARBON CONCENTRATION IN SUB-ANNUAL TREE RINGS FROM POLAND AROUND 660 BCE

ABSTRACT The article presents results of measurements of radiocarbon (14C) concentration in sub-annual dendrochronologically dated tree rings of English oak (Quercus robur L.) from Grabie village near Kraków (southern Poland). Samples of early wood (EW) and late wood (LW) spanning the years 664–658 BCE. α-cellulose was extracted from each sample and their radiocarbon content was measured at the ATOMKI laboratory in Debrecen, Hungary. The EW and LW data confirm a prolonged increase in Δ14C values around 665–663 as was observed by Park et al. (2017), Rakowski et al. (2019), or Sakurai et al. (2020). In addition, we found that this event may consist of two relatively small events, as was proposed by Sakurai et al. (2020). Based on obtained in this and previous study data we estimate that the occurrence of the two events were between 665 and 664 BCE (Rakowski et al. 2019), and in late spring of 663 BCE (May–June, before beginning of LW formation).

Thermal softening properties of various wood species within an annual ring

Dynamic mechanical analysis (DMA) measurements of water-saturated earlywood (EW) and latewood (LW) of various wood species in the temperature range from 0 to 100 °C were focused to clarify the differences in thermal softening properties within an annual ring. The following results were obtained. The peak of tanδ caused by micro-Brownian motion of lignin was observed in both EW and LW all species. For softwoods, the peak temperatures of tanδ of EW appeared at higher temperatures than those of LW. For hardwoods, in the other hand, the peak temperatures of tanδ were slightly different between EW and LW in the diffuse-porous wood, whereas the temperatures were almost the same in the ring-porous wood. It was found that the difference in peak temperature of tanδ between EW and LW varied greatly among species. The difference in peak temperature between EW and LW was relatively large for softwoods. In addition, the thermal softening properties both in the radial and tangential directions differed depending on the species, so this suggested that there was anisotropy in the thermal softening properties depending on the species.

The potential of using the Blue Intensity parameter to assess the climate response of radial tree growth on the Crimean peninsula

The results of assessing the climate signal contained in the width of tree rings and the indicator of optical density of wood (Blue Intensity) of related species of pine trees – black (Pinus nigra Arnold) and Pitsunda (Pinus brutia Ten) growing on the southern coast of the Crimean peninsula are presented. The influence of the cumulative effect of moisture deficiency on the radial growth and lignification processes of late wood of the studied conifer species is shown. A specific reaction of P. nigra in high mountain areas to conditions of prolonged drought was revealed. The prospects for using the Blue Intensity indicator for dendroclimatic studies on the territory of the Crimean Peninsula have been demonstrated.