Wood Zone Research Articles

Dynamic of land use and vegetation change in the eastern bank of Bénoué (North Cameroon).

The eastern part of the Benoue River bank is undergoing degradation marked by a significant decrease in vegetation cover and woody resources due to anthropogenic activities and climatic. The main objective of this study is to analyze the farmers' knowledge of vegetation evolution and the dynamics of land use using satellite images in the east of the bank of the Benoue. The methodological approach used is an integrated one combining field surveys, remote sensing, mapping, and modeling. The results obtained show that 88% of the population surveyed believe that the area covered by vegetation has decreased. The reasons for this decrease are numerous, but the main one remains the strong anthropic activity that would be at the origin of the progressive degradation of the land. The evolutionary trend of plant formations is essentially regressive for natural formations from 1991 to 2021. The analysis of the evolution of land use showed that in the Rey-Bouba district during 1991, 58.24% of the area formerly made up of dense woody formations regressed considerably to 25.77% in 2021. The same is true for the Bibemi district where the area of wooded zone has decreased from 65.47% in 1991 to 28.45% of the total area in 2021. This regression of the surface area of wooded formations was done to the benefit of anthropized occupation classes whose area has increased. They suggest an effective awareness in the monitoring of the dynamics of the vegetation cover subjected to anthropic pressures and climatic variations for a better-integrated management of the vegetation of this area.

Картографирование лесных насаждений Волгоградской области по данным ДЗЗ с использованием индексов BSFI и NDWI

The possibilities of adjusting the results of mapping wood plantations based on the bi-seasonal forest index (BSFI) according to Sentinel-2 data and calculated seasonal composite images of the NDWI index maximum values are presented. It was found out that with using a seasonal composite image of the mentioned values, calculated with the NIR and SWIR2 ranges, the manufacturer`s accuracy in raster cross-validation increases from 82,5 to 92,8 %. At the same time, the initial areas of wood zones decreased by 7 %, and those of false identifications shrank by 67 %. Comparison of mapping results with statistical data showed small differences in areas with a large number of natural forest plantations (in 18 of 33 areas they do not exceed 15 % of the design ones). Moreover, in lands with a large number of protective green spaces, discrepancies can reach up to 210 % of the design values. It is shown that significant distinctions in design and actual mapping materials can be associated with poor preservation, fires, illegal logging, as well as problems of accounting protective forest plantings. A fairly accurate method for adjusting BSFI was proposed (the manufacturer’s accuracy increased from 82,5 to 92,8 %) based on the maximum composite NDWI image calculated using the NIR and SWIR2 bands of the Sentilel-2A and Sentilel-2B satellites in a test area within the Volgograd region

Moisture Content of Fresh Scots Pine Wood in Areas near Damage Caused by Harvester Head Feed Rollers

By damaging bark, mechanized harvesting deprives wood of its natural mechanical barrier. This study concerns the effect of this damage on the changes in moisture content that occur near the damaged areas of Scots pine (Pinus sylvestris L.). This study was carried out using 45 randomly selected 11 m long logged pine stems. Additionally, the effect of bark thickness on the depth of damage was measured. To determine the influence of the location of the damage and bark thickness on the wood moisture near the damaged region, wood samples were collected from two sections. The first was located one meter above the log’s base, while the second was located one meter from the end of the log. Two increment cores were taken by a Pressler borer in each section: one from the damaged wood zone and the second from the undamaged wood zone. The average bark thickness one meter from the base of the log was 11.2 mm, which decreased to 1.8 mm in the samples taken one meter from the top of the log. The average depths of the damage caused by feed roller spikes in the two sections were 3.9 and 3.8 mm, respectively, indicating that there was no significant effect of bark thickness on the depth of the damage. The wood samples collected near the damaged wood zone (DW) had about 13 percent lower moisture content than those taken from the undamaged zone (UDW). This difference was statistically significant. We observed greater mean moisture content closer to the top of the log for both the samples taken near the damaged zone and the samples taken from the undamaged zone. One meter from the base of the log, the moisture content difference between the DW and UDW was 9.8 percentage points, which was statistically insignificant. By contrast, significantly lower moisture content (−16%) was observed in the DW one meter from the top of the log.

Analysis of the structure and fertility of agricultural land in western Ukraine and its monetary assessment

An important sector of the Ukrainian economy is agriculture, which is based on the fertility of agricultural land, in particular, the land of the western region of Ukraine. Analysis of the structure, fertility of agricultural land, and its monetary valuation can provide insight into its productivity and potential for agricultural development. The purpose of the study is to analyse the structure and fertility indicators of agricultural land in the west of Ukraine, demonstrate their main characteristics, and compare land prices in the western regions of Ukraine. In the study, the materials of the land directory of Ukraine and regional reports on the state of the environment of the west of Ukraine were used, involving analysis and comparison of the state of land resources by the content of humus, mobile compounds of phosphorus and potassium, easily hydrolysed nitrogen, their material and monetary assessment. After analysing the structure of the land fund of the west of Ukraine (13125.5 thousand hectares), it was identified that agricultural land accounts for more than half of the total area (56.1%), and forests and other wooded zones – about a third of the total area (32.8%). Built-up land, open wetlands, open land without vegetation cover or with little vegetation cover, and other land account for less than 10%. Among agricultural land, the largest share is arable land, a little less is hayfields and pastures, and the least is perennial plantations and fallows. The total value of agricultural land in the western administrative regions is markedly different. The highest land value is in Khmelnytskyi and Ternopil regions (1.71 and 1.09 billion USD), and the smallest – in Ivano-Frankivsk and Zakarpattia (489.90 and 317.21 million USD). 1420223 shares were leased on the territory of western Ukraine. The largest number of them was leased in Khmelnitsky and Ternopil regions (25.2 and 20.7%), and the smallest – in Zakarpattia (1.0%). Thus, the total area of land cultivated by farmers is 330.8 thousand hectares, the largest in the Ternopil and Khmelnytskyi regions (23.3 and 22.7%). The findings of the study will contribute to the adoption of managerial decisions on conducting efficient agriculture and the preservation of soil fertility of agricultural lands in the region under study. Monetary assessment of these territories is useful for the country’s population in the context of changes in the law on the land market in Ukraine, and in the implementation of an environmentally balanced agricultural policy

Concept of a photon spatial switch based on an off-axis zone plate: experimental confirmation in the millimeter waves range

We present results of the experimental verification of a concept of the previously proposed all-optical wavelength-selective multichannel switch based on an off-axis Wood zone plate in the millimeter waveband without the use of micromechanical devices or non-linear materials. A laboratory prototype of such a device is considered and its main parameters are discussed. It is shown that the optical isolation of switched channels for the switch based on an off-axis zone plate can reach 15 dB at a frequency difference of 25 GHz in the frequency range of 93 – 136 GHz.

REVIEW OF DYNAMIC PROPERTIES OF WOOD

This review considers the state of the art in the field of theoretical and experimental studies of dynamic deformation and destruction of wood materials. The orthogonal properties of wood, features of early and late wood are considered, the dynamic properties of wood are analyzed, as well as the influence of the strain rate during dynamic compression. It is noted that wood of different species is mainly used as one of the materials that dampen dynamic loads as a result of impacts or explosions. For example, it can mitigate the effects of high-velocity impacts on the contents of containers during the transport of hazardous materials by air, road and rail. It has been established that the cause of the effects of internal friction in wood are the areas of lignin, in which bundles of cellulose molecules (microfibrils) with a diameter of 25-30 nm are immersed, which are crystalline in their structure, which leads to viscoelastic behavior - internal damping. To improve the damping properties, it is recommended to choose wood with a low microfibril angle. It is noted that the stress-strain curve under dynamic compression of wood consists of three separate parts: the initial elastic region, the yield region and the compaction region. The main characteristics of compression, that is, the components of the stress-strain curve and the destruction of the fibers, do not depend on temperature. Young's modulus is much larger in the longitudinal direction than in the radial and tangential directions. The rate of deformation, temperature and humidity have a great influence on the strength properties of wood. The features of the mechanical behavior of the zones of early and late wood in the massif of a tree trunk are considered. Late wood is more rigid than early wood. As a result, differences in the mechanical properties of the wood fibers during compression may cause the early wood fibers to be destroyed while the late wood fibers remain intact. Due to the complexity of the wood structure, its reliable description by a numerical model requires complex models that take into account not only the influence of temperature, strain rate, and the type of stress-strain state, but also the angle between the direction of loading and the direction of wood fibers. Two main groups of wood material models are considered: micromechanical models simulating the details of the wood structure, and continuum models simulating the behavior of wood as a whole.

Оценка и картографирование природной пожарной опасности растительности Байкальского региона

The relevance of the work is due to the high natural fire danger of vegetation in the area of the Baikal region (the Irkutsk oblast, the Republic of Buryatia and Zabaykalsky Krai). In this regard, it is important to analyze and identify the local types of plant complexes, assess their natural fire hazard by the characteristic signs of the presence and distribution of plant combustible materials. Based on statistical data for 2000–2020, indicators of fire risk and density, and the area of one burning case were calculated for wood zones. The types of plant complexes are analyzed and identified using the cartographic method. They are evaluated in accordance with the basic principles of forest combustible materials’ fire hazard with the assignment of appropriate classes of natural burning ability to them. The results of the study are reflected on a small-scale map Natural fire danger of vegetation of the Baikal region, which can serve for territory-wide interaction in matters of fire monitoring. It is determined that a significant part of the area’s vegetation has a high and medium natural fire hazard. The highest of that is observed in the southern and central parts of the mentioned lands.

Influence of Four Spacings between Trees and Four Samplings Heights on Selected Wood Quality Attributes of White Spruce (Picea glauca (Moench) Voss)

Four Picea glauca (Moench) Voss trees grown at each of four square spacing intensities between trees: 1.2 m, 1.8 m, 4.3 m, and 6.1 m in a plantation established in 1967 in the Petawawa Research Forest, Ontario, Canada (lat. 45.59° N, long. 77.25° W, elev. 168 m) and sampled at four different heights (1.3 m, 4.3 m, 7.3 m, 10.3 m) were used to study the impact of spacing between trees and sampling height on nine wood quality attributes (ring width, ring density, tracheid length, tracheid diameter, latewood proportion, intra-ring density variation, ring area, earlywood width, and latewood width). In the juvenile wood, ring width was wider and ring density higher than in the mature wood. Tracheid length was longer and tracheid diameter wider in the mature wood compared to the juvenile wood. The variation of ring density between the two wood zones was limited, and latewood proportion did not show any difference with wood zone. Sampling height induced variation in more wood quality attributes than did spacing. Except for growth rate, spacing between trees did not significantly impact wood quality attributes. Most of these variations were registered between widely different spacings.

Experimental Proof-of-Concept of a Spatial Photonic Switch Based on an Off-Axis Zone Plate in Millimeter Wavelength Range

Optical switches are key elements in modern network communications. We present the results of the experimental verification of a new theoretical concept proposed earlier for a full-optical wavelength-selective dual-channel switch based on the photonic hook effect, which is free from using any micro-mechanical devices or nonlinear materials. A large-scale laboratory prototype of such a device based on an off-axis Wood zone plate is considered, and its main parameters in the millimeter wavelength range are investigated. On the basis of the experiments, we show that the optical isolation of switched channels for a switch based on an off-axis zone plate can achieve 15 dB at a frequency difference of 25 GHz in a frequency range of 93 to 136 GHz. Given the scaling, these results can be transferred to another range, including the optical one.

Using long-term citizen science data to distinguish zones of debris accumulation.

Studies show that a driver of coastal debris is the rate between debris deposition and resuspension; however, the influence of beach zone topography on the distribution of debris remains poorly understood. Using five years of marine debris data collected by the COASST citizen science program, we explored the spatiotemporal trends in debris abundance within two regions of the United States Pacific Northwest and investigated whether higher debris loads are associated with beach zones that have a higher propensity to trap debris. We found that beaches with larger wood zones had higher debris loads, adding to the growing evidence that backshore areas of beaches act as sinks for debris. Higher debris loads were also associated with beaches that had larger wrack zones suggesting that onshore transport from the marine reservoir is a dominant source of debris. This study provides a long-term baseline of marine debris which managers could use to inform source reduction interventions.

Transverse permeability in Eucalyptus nitens wood specimens

ABSTRACT Permeability functionalities are noticeable in the wood drying and impregnation processes because it has an effect on the bulk flow of a fluid through the wood structure. The aim of this work was to measure the radial and tangential specific gas permeability of Eucalyptus nitens wood for 10 different provenances. Furthermore, the effect of the radial position (defined as inner-wood, middle-wood, and outer-wood) on the measurements was investigated. The specific gas permeability of E. nitens ranged in order of magnitude from 10−20 to 10−16 m2. The results showed that the radial position had a statistically significant effect on the specific permeability in both flow directions and, in general, the permeability values increased from inner-wood to outer-wood. Moreover, the scanning electron microscopy images showed obstruction of vessels by tyloses which explained the lower permeability values obtained in the inner-wood of E. nitens. Differences in the magnitude of the permeability values could explain the diverse drying and impregnation behavior according to the wood zones, the low permeability values in the internal wood-zone could suggest an opportunity for improving it, through chemical modification or structural changes to introduce new functionalities of this radial wood-zone in Eucalyptus nitens.

Anatomy of Pinus mugo var. mugo as a fundament for annual-ring-based dating of debris flows in the alpine zone

Dendrogemorphic methods are a very accurate tool for dating past debris flows. Chronological data are very valuable, especially in the alpine zone, because climate change has a very intense impact on the frequency of debris flows here. However, at the same time, the applicability of dendrogeomorphic methods in this environment is limited by the lack of suitable trees. Shrub-like mountain pine (Pinus mugo var. mugo) is often the only tree species in this environment, however, dating using a classical macroscopic approach including the analysis of annual-ring series is frequently challenging due to difficulties with detection of increment growth disturbances. Thus, this study focuses on the possibility of detecting growth responses of P. mugo to debris flow exposure at the anatomical level.A total of 14 P. mugo specimens were sampled using discs through stem scars. Anatomical analysis was performed on microsections realized in two radial segments on each stem disc (one as a control). In each segment, five consecutive annual rings (two before damage, one damaged and two after damage) were analyzed each divided into early and late wood zones. The results showed a significant reduction in tracheid parameters (cross-sectional area, radial width, and tangential width) in the early wood zone. Another significant anatomical response was found as an increase in the number of radial rays. Possible effects of scar size and shrub age on the intensity of the anatomical response are also discussed. Thus, this study demonstrated the potential applications of anatomical analyses of P. mugo and suggested new possibilities for dating debris flows within the limit zone of applicability of dendrogeomorphological methods.

Experimental study of compressive properties parallel to grain of glulam

This paper describes results and analysis of experiment of compression behavior parallel to grain of glulam (Norway Spruce, Japanese cedar, and Japanese cypress), especially in damage zones near loading plates and joints. To investigate the influence factors of physical properties and the mechanism of the damage zone near the loading plates or the joints, compression tests on 90 specimens and surface-measurement tests on 48 specimens were performed. As a result, it was observed that damage zones existed near the loading plates and the joints. The lengths of the damage zone of wood–wood joints are larger than that of wood–steel joints. The length of the damage zone was independent of the load and the height of the specimens. However, the length of the damage zone and its scatter increase as the width of the cross-section increases, as does the roughness on the contact surface. It was considered that the cause of the damage zone is the roughness on the contact surface and the length of the damage zone depends on the roughness on the contact surface. Therefore, the length of the damage zone depends on the processing accuracy on the contact surface and has an increasing trend as the contact-surface area increases. There was the size effect of the height of the specimens on the compressive strength because of knots.

Analysis of quantitative and qualitative extractive components extracted from hornbeam (Carpinus betulus L.) and yakal (Shorea astylosa Foxw.) wood

The aim of the study was analysis of quantitative and qualitative extractive components extracted from hornbeam (Carpinus betulus L.) and yakal (Shorea astylosa Foxw.) wood. Two wood species similar to each other in terms of microscopic structure and physical properties, the native wood of Hornbeam (Carpinus betulus L.) and the yakal wood (Shorea astylosa Foxw.) endemic to the Philippines, which is still little understood, were investigated. Wood is a material composed mainly of polymers called lignocellulose which includes: (cellulose, lignin and hemicelluloses), but also contains many extractive and mineral substances. . The extractive content of wood in temperate climates is approximately for up to 5% by weight of wood. Their identification is difficult because of the wide variety and multiplicity of compounds present. However, extractive compounds are important for the resistance of trees and wood to biological agents such as fungal infestation or insect infestation. Usually the zones of dead wood (heartwood or cored wood) are characterized by a higher content of extractives. The understanding of the chemical composition of extractives in wood can contribute to the development of wood preservative products and environmentally friendly and would be part of the green chemistry policy.

LATERAL GROWTH AFFECTS XYLEM MATURATION PROPERTIES OF 8-YEAR-OLD BIG-LEAF MAHOGANY (SWIETENIA MACROPHYLLA)

The area of juvenile wood zone of an 8-year-old planted big-leaf mahogany (Swietenia macrophylla) was uniform regardless of diameter. Hence, it was assumed that xylem maturation is dependent on diameter. Radial distribution patterns with reference from the pith exhibited short fibre and vessel lengths, narrow vessel width and low xylem density, and exhibited gradual increase outward and became more or less stable near the bark. However, the radial distribution patterns of fibre width and modulus of elasticity were scattered regardless of tree diameter sizes. Fibre length, vessel length, vessel width and xylem density of the juvenile wood zones showed significant differences compared with the transition and mature wood zones. However, no significant difference was observed between transition wood zone and mature wood zone except for fibre length. A negative correlation was observed in fibre length, vessel length, vessel width and xylem density in terms of their relationship with diameter at breast height and the radial distribution of fibre (i.e. b-value), and the diameter boundaries of the three wood zones. At diameters 18.08, 17.36, 16.23 and 17.87 cm respectively, fibre length, vessel length, vessel width and xylem density can be used to identify xylem maturation boundary.

Dynamic Landscape Fragmentation and the Driving Forces on Haitan Island, China

Island ecosystems have distinct and unique vulnerabilities that place them at risk from threats to their ecology and socioeconomics. Spatially exhibiting the fragmentation process of island landscapes and identifying their driving factors are the fundamental prerequisites for the maintenance of island ecosystems and the rational utilization of islands. Haitan Island was chosen as a case study for understanding landscape fragmentation on urbanizing Islands. Based on remote sensing technology, three Landsat images from 2000 to 2020, landscape pattern index, transect gradient analysis, and moving window method were used in this study. The results showed that from 2000 to 2020, impervious land increased by 462.57%. In 2000, the predominant landscape was cropland (46.34%), which shifted to impervious land (35.20%) and forest (32.90%) in 2020. Combining the moving window method and Semivariogram, 1050 m was considered to be the best scale to reflect the landscape fragmentation of Haitan Island. Under this scale, it was found that the landscape fragmentation of Haitan Island generally increased with time and had obvious spatial heterogeneity. We set up sampling bands along the coastline and found that the degree of landscape fragmentation, advancing from the coast inland, was decreasing. Transects analysis showed the fragmentation intensity of the coastal zone: the north-western and southern wooded zones decreased, while the concentration of urban farmland in the north-central and southern areas increased. The implementation of a comprehensive experimental area plan on Haitan Island has disturbed the landscape considerably. In 2000, landscape fragmentation was mainly influenced by topography and agricultural production. The critical infrastructure construction, reclamation and development of landscape resources have greatly contributed to the urbanisation and tourism of Haitan Island, and landscape fragmentation in 2013 was at its highest. Due to China’s “Grain for Green Project” and the Comprehensive Territorial Spatial Planning policy (especially the protection of ecological control lines), the fragmentation of Haitan Island was slowing. This study investigated the optimal spatial scale for analyzing spatiotemporal changes in landscape fragmentation on Haitan Island from 2000 to 2020, and the essential influencing factors in urban islands from the perspective of natural environment and social development, which could provide a basis for land use management and ecological planning on the island.

Изменчивость длины трахеид сосны обыкновенной в зависимости от лесотипологических условий

The article provides a comparative analysis of the lengths of early and late tracheids of dominant coeval Scots pine trees. It has been established that tracheids of juvenile wood are characterized by significant differences in length and the difference between them reached 400%, while in the zone of mature wood, the length of both early and late tracheids stabilizes, demonstrating small fluctuations (in within 10%). That makes it possible to use the obtained results to assess forest typological variations. It was shown that the longest tracheids were found in sorrel pine forests, and the shortest – in sphagnum; ericetal pine forests showed intermediate results. The idea of significant differences between the lengths of tracheids in the zone of mature wood of model trees of 3 trial plots is substantiated.

Radial growth patterns of Siberian larch in plantations of the Republic Mari El

Based on the measurements of 83 wood cores, the main patterns of changes in the width of the early and late zones in the annual ring of Siberian larch trees (Larix sibirica Ledeb.), as well as their total radial growth indices in the conditions of the Republic of Mari El were identified. It was found that the width of the early wood zone varies in trees from 0.15 to 11.3 mm, late wood – from 0.05 to 4.15 mm, the proportion of latewood – from 1.2 to 82.8 %, and the annual growth indices - from 13 to 423 %. The main factor in the variability of the total width of the annual rings and the layer of early wood is the age of the trees, and the contribution of weather conditions and other unaccounted factors (noise) to the overall variance of the annual growth parameters is no more than 20 %. The variability of the total width of the annual ring also depends on their genotypic features, which determine up to 42.7% of the total variance of the parameter in some cenopopulations. In the dynamics of the growth indices of larch trees, despite the existing specifics of each cenopopulation, the general sharp decline in their values after the droughts of 1972 and 2010, as well as the alternation of the periods of growth and decline, is clearly distinguished.

Interpreting research results for the physical and mechanical properties of wood: An approach not dependent on a juvenile/mature wood boundary

The interpretation and presentation of research on the physical and mechanical properties of wood in the radial direction is important for the estimation of technological properties in primary wood processing. It is common practice to define the boundary between the juvenile and mature wood zone of tree growth because of the differences in wood properties in these two zones. The juvenile and mature wood zones can be determined statistically based on the significance of the difference in the properties in a particular zone. This paper presents the insufficiency in the statistical determination of the boundary between juvenile and adult wood. Such limitations detract from the potential value and technological exploitation of wood as raw material. Statistical tests yielded zones that were too wide for the transition of juvenile wood to mature wood. Representations of the distribution of properties in the radial direction also complement the knowledge for assessing the technological properties based on the researched use of the presentation of polynomials of the second degree and the display of the Tukey HSD test in the form of comparison tables. The graphical representations by groups of the tested annual rings of fir wood also help to assess the technological properties.

Spatial variability of surface peat properties and carbon emissions in a tropical peatland oil palm monoculture during a dry season

AbstractThe expansion of oil palm monocultures into globally important Southeast Asian tropical peatlands has caused severe environmental damage. Despite much of the current focus of environmental impacts being directed at industrial scale plantations, over half of oil palm land‐use cover in Southeast Asia is from smallholder plantations. We differentiated a first generation smallholder oil palm monoculture into 8 different sampling zones, and further divided the 8 sampling zones into oil palm root influenced (Proximal) and reduced root influence (Distal) areas, to assess how peat properties regulate in situ carbon dioxide (CO2) and methane (CH4) fluxes. We found that all the physico‐chemical properties and nutrient concentrations except sulphur varied significantly among sampling zones. All physico‐chemical properties except electrical conductivity, and all nutrient content except nitrogen and potassium varied significantly between Proximal and Distal areas. Mean CO2 fluxes (ranged between 382 and 1191 mg m−2 h−1) varied significantly among sampling zones, and between Proximal and Distal areas, with notably high emissions in Dead Wood and Path zones, and consistently higher emissions in Proximal areas compared to Distal areas within almost all the zones. CH4 fluxes (ranged between −32 and 243 µg m−2 h−1) did not significantly vary between Proximal and Distal areas, however significantly varied amongst sampling zones. CH4 flux was notably high in Canal Edge and Understorey Ferns zones, and negative in Dead Wood zone. The results demonstrate the high heterogeneity of peat properties within oil palm monoculture, strengthening the need for intensive sampling to characterize a land use in the tropical peatlands.