Wood Density Research Articles

Soil carbon and wood decay models in Nigeria’s Niger Delta environment

Decaying of wood is a major factor in modelling global carbon emissions and their effect on climate change. When not properly considered, trees used in urban greening have been observed to cause hazards and do a disservice in terms of carbon storage due to their degradation. This degradation process is aided by species properties and climatic and biological factors, but the quantitative characteristics of this process on commonly used avenue trees in Nigeria are scarce. The decay rate of wood-block samples of six commonly used avenue trees (Azadirachta indica, Gmelina arborea, Delonix regia, Casuarina equisetifolia, Musanga cecropiodes, and Ficus elastica), as well as soil carbon changes beneath the wood blocks, were monitored under natural varying climatic conditions (Soil temperature, air temperature, relative humidity) and incidence of termite attack over a period of 16 weeks. Soil and air temperature showed a quadratic trend with decay rate, with p-values less than 0.05 and 0.10, respectively, while density and incidence of termite attack were negatively linear (p<0.05) and positively linear (p<0.01), respectively. Among the species, D. regia had the highest coefficient for predicting decay rate. Soil depth and wood density were significant predictors of soil carbon accumulation from decaying wood samples. Soil temperature and other climatic variables of a region should be considered for various tree planting and management projects to discourage the selection of trees with a high decay rate and carbon loss in the area, such as D. regia.

Allometric Relationships of Branch Water-Storage Capacity and Capacitance in Four European Trees Species.

Water storage capacity and capacitance in trees regulate hydration levels, providing water reserves during drought. However, the effects of varying traits, tissue fractions and of different water pools on the allometry of branch-/sample-level properties have not been systematically investigated. We analyse the relationships between branch size and branch capacity and capacitance with respect to wood density, xylem vulnerability to embolism, and tissue fractions. The analysis was performed using data from four tree species sampled from 12 to 15 sites across Europe. We show that of the three phases of the water release curve, the second phase (dominated by elasticity) was significantly influenced by leaf and bark proportions, the sapwood/heartwood ratio and xylem vulnerability to embolism for capacity and/or capacitance. However, the first (dominated by capillarity) and the third phase (characterised by embolism) were not influenced by the morpho-physiological properties measured. Our results indicate that branch capacity and capacitance are allometrically related (slope < 1) to branch dry mass, leaf area and total water content, indicating that normalising by these size measures does not completely remove size-dependency. We conclude that the only means of obtaining size-independent water storage traits directly applicable in comparative and modelling studies is by normalising by water quantity per phase.

Analysis of Wood Density to Compare the Amount of Accumulated Carbon Dioxide in the Stems of Selected Non-Native Tree Species in Poland

One of the priorities in European policy is the greater use of wood. In this context, it is important to know the total amount of CO2 absorbed by the tree and accumulated in the wood. In the timber industry, butt logs are mainly processed. The aim of this study is to analyze diameter at breast height (DBH), wood density (WD), and the amount of CO2 in grand fir (GF), Douglas fir (DF), northern red oak (NRO), and black locust (BL) wood. The DBH and bark thickness were measured, and cores were taken to study WD and calculate the amount of CO2. Analyses were conducted in three age classes of trees. It was found that in the youngest age class, DF had a significantly larger DBH compared to NRO and BL, and GF had a significantly larger DBH compared to NRO. The wood density of coniferous species was significantly lower compared to broadleaved species. DF absorbed the most CO2. In Class III, DF had significantly larger DBH and significantly lower wood density compared to NRO and BL. DF absorbed significantly more CO2 compared to NRO. In Classes IV and V, DF had larger DBH compared to NRO and lower wood density. The amount of CO2 absorbed by both species was similar. Taking into account the amount of absorbed CO2, the durability of the wood, and aspects related to sustainable forest management of the four studied non-native tree species, Douglas fir seems to be the best choice for cultivation in Polish forests.

Insights into the subdaily variations in methane, nitrous oxide and carbon dioxide fluxes from upland tropical tree stems.

Recent studies have shown that stem fluxes, although highly variable among trees, can alter the strength of the methane (CH4) sink or nitrous oxide (N2O) source in some forests, but the patterns and magnitudes of these fluxes remain unclear. This study investigated the drivers of subdaily and seasonal variations in stem and soil CH4, N2O and carbon dioxide (CO2) fluxes. CH4, N2O and CO2 fluxes were measured continuously for 19 months in individual stems of two tree species, Eperua falcata (Aubl.) and Lecythis poiteaui (O. Berg), and surrounding soils using an automated chamber system in an upland tropical forest. Subdaily variations in these fluxes were related to environmental and stem physiological (sap flow and stem diameter variations) measurements under contrasting soil water conditions. The results showed that physiological and climatic drivers only partially explained the subdaily flux variations. Stem CH4 and CO2 emissions and N2O uptake varied with soil water content, time of day and between individuals. Stem fluxes decoupled from soil fluxes. Our study contributes to understanding the regulation of stem greenhouse gas fluxes. It suggests that additional variables (e.g. internal gas concentrations, wood-colonising microorganisms, wood density and anatomy) may account for the remaining unexplained variability in stem fluxes, highlighting the need for further studies.

Impact of salinity on density and mechanical strength of &lt;i&gt;Avicennia germinans&lt;/i&gt; wood exposed to marine oil pollution in the Gabon Estuary

Located at the interface between land and sea, mangroves develop both near the sea and inland. However, mangroves that develop inland have to cope with variable, high salinity; and urban pollution, as is the case with the mangroves of the Ambowé lagoon in Greater Libreville. Salinity is an important parameter for mangrove growth. The aim of this work was; yes itto show the impact of salinity on the density and mechanical strength of A. germinans wood exposed to hydrocarbon pollution. To this end, wood samples taken from the polluted Ambowé site were analyzed in the laboratory for wood and physical-mechanical properties. The data obtained were compared with wood samples taken from the unpolluted Oveng site, which has a higher salinity. The results show that for the polluted wood showed wider rings, lower wood density and mechanical strength with values of 0.91 ± 0.05 and 70.28 MPa, respectively. Also, the rings and vessels of Oveng wood are narrower than those of Ambowé wood. These differences are linked to salinity. Salinity therefore affects the density and mechanical strength of A. germinans wood exposed to hydrocarbon pollution.

Measuring wood density of different tree species using the micro-drilling resistance method

Measuring wood density of different tree species using the micro-drilling resistance method

Salt stress tolerance strategies vary between different functional groups of plants of native semi-arid species

The increase in salinity in dry regions has contributed to the desertification of areas, increasing the need to identify tolerant species. The investigation of functional groups of plants clarifies adaptation strategies; however, in a saline environment, it has not yet been explored. The objective was to investigate how different functional groups of Caatinga plants respond to increased saline stress. Plants of deciduous species with high wood density (HWD) (Myracrodruon urundeuva and Bauhinia cheilantha), and deciduous species with low wood density (LWD) (Amburana cearenses and Pseudobombax marginatum) were evaluated. The saline concentrations (NaCl) were 0.15; 2.5; 3.5 and 4.5 dS m-1 applied for 90 days. A completely randomized design was adopted in a 2 × 2 × 4 factorial scheme with five replications. At the end of the experiment, growth, stomatal conductance (gs), water potential (Ψxylem), chlorophyll fluorescence, salt content and enzymatic activity were analyzed. The data were subjected to polynomial regression analysis and Tukey test (5 %). The HWD group was classified as salinity tolerant and presented high values of gs (300 mmol m-2s-1), variation in Ψxylem (70 %), efficiency of photosystem II, number of leaves, and accumulation of salts in the leaves (K+ = 70 %, Na+ = 18 %, and Cl- = 52.5 %). On the other hand, the LWD group was classified as moderately sensitive to salinity and showed a large reduction in growth and biomass with increased salinity, accumulation of ions in stem (Cl- = 136 %) and root (Na+ = 44 %; Cl- = 45 %), and higher enzymatic activity (45 %). Tolerance strategies to saline stress differ between different functional groups of Caatinga seedlings. The HWD group is more tolerant to salinity and represents a good alternative for the recovery of salinized areas.

Putting seedlings on the map: Trade-offs in demographic rates between ontogenetic size classes in five tropical forests.

All species must partition resources among the processes that underly growth, survival, and reproduction. The resulting demographic trade-offs constrain the range of viable life-history strategies and are hypothesized to promote local coexistence. Tropical forests pose ideal systems to study demographic trade-offs as they have a high diversity of coexisting tree species whose life-history strategies tend to align along two orthogonal axes of variation: a growth-survival trade-off that separates species with fast growth from species with high survival and a stature-recruitment trade-off that separates species that achieve large stature from species with high recruitment. As these trade-offs have typically been explored for trees ≥1 cm dbh, it is unclear how species' growth and survival during earliest seedling stages are related to the trade-offs for trees ≥1 cm dbh. Here, we used principal components and correlation analyses to (1) determine the main demographic trade-offs among seed-to-seedling transition rates and growth and survival rates from the seedling to overstory size classes of 1188 tree species from large-scale forest dynamics plots in Panama, Puerto Rico, Ecuador, Taiwan, and Malaysia and (2) quantify the predictive power of maximum dbh, wood density, seed mass, and specific leaf area for species' position along these demographic trade-off gradients. In four out of five forests, the growth-survival trade-off was the most important demographic trade-off and encompassed growth and survival of both seedlings and trees ≥1 cm dbh. The second most important trade-off separated species with relatively fast growth and high survival at the seedling stage from species with relatively fast growth and high survival ≥1 cm dbh. The relationship between seed-to-seedling transition rates and these two trade-off aces differed between sites. All four traits were significant predictors for species' position along the two trade-off gradients, albeit with varying importance. We concluded that, after accounting for the species' position along the growth-survival trade-off, tree species tend to trade off growth and survival at the seedling with later life stages. This ontogenetic trade-off offers a mechanistic explanation for the stature-recruitment trade-off that constitutes an additional ontogenetic dimension of life-history variation in species-rich ecosystems.

Physicochemical and mechanical characterization of Brosimum lactescens and Parkia discolor wood from Guaviare, Colombia

Colombia has numerous wood species of great importance; however, information on many of these species is scarce. For this reason, the woods Guaimaro (Brosimum lactescens) and Dormidero negro (Parkia discolor) cultivated in Calamar (Guaviare) were studied, with the aim of determining their properties and enhancing their rational use. The evaluations were carried out following the Colombian Technical Standards NTC 290, 663, 701 and 784. Density was evaluated according to NTC 290; shrinkage and stability coefficient were determined following the NTC 701; the holocellulose content was according to the procedure of Wise, the lignin content and extractives were determined as described by TAPPI T 222 and T 204; the mechanical bending strength with NTC 663 and to calculate the parallel compression under the NTC 784. The Guaimaro is a very dense wood, dimensionally stable and of high resistance to bending and parallel compression being of optimal use for construction with extractives of 18.52%, holocellulose of 65.59% and lignin of 35.81%; it presents higher lignin contents than other species of the same genus. The Dormidero negro has a medium density, low dimensional stability, and low resistance to static bending and parallel compression. It is not suitable for construction, but it can be used for carpentry. The chemical composition was consistent with that of other species in the same genus, with extractives at 15.88%, holocellulose at 69.30%, and lignin at 31.77%. Expanding mechanicaltests, such as hardness and shear tests, is recommended, along with exploring treatments to enhance its properties.

Do wood-boring beetles influence the flammability of deadwood?

Global warming increases the risk of wildfire and insect outbreaks, potentially reducing the carbon storage function of coarse woody debris (CWD). There is an increasing focus on the interactive effects of wildfire and insect infestation on forest carbon, but the impact of wood-boring beetle tunnels via their effect on the flammability of deadwood remains unexplored. We hypothesized that the presence of beetle holes, at natural densities, can affect its flammability positively through increased surface area and enhanced oxygen availability in the wood. To test this, wood-boring beetle holes were mimicked experimentally in decaying logs of two coniferous species, and flammability variables of these treated logs were compared. We found that wood-boring beetles partly increased the flammability of CWD of both species (via promoting deadwood smoldering combustion) when their holes were parallel with the airflow. Even when accounting for the influences of wood density and cracks, these radial holes continued to have a notable impact on deadwood flammability. While these holes did not make the wildfire more intense, they significantly increased carbon loss during combustion. This suggests that wood-boring beetles will enhance carbon release from deadwood into the atmosphere during wildfire.

Functional responses of Mediterranean flora to fire: A community‐scale perspective

Abstract Fire regime is predicted to change, particularly in Mediterranean climate regions, towards more severe and frequent fire events. From a predictive perspective, trait‐based ecology offers a comprehensive framework to characterize vegetation responses to fire. Since fires induce erosion and decrease soil nutrients, species' functional traits and their distribution at community level should reflect these changes. Despite a vast literature focused on plant traits involved in resistance to fire, quantification of community trait responses to fire is lacking, particularly for traits that are linked to resource strategies. Here, we emphasis on plant traits related to morphology (height, specific leaf area, stem and wood density) and resource acquisition strategies (leaf nitrogen, leaf dry mass, seed dry mass). We compiled three different databases compiling vegetation, fire and functional traits for the flora of Southern France. We analysed the relationships between these three components at both species and community levels. Fire numbers and area burnt did not impact species trait distributions. At community level, a clear pattern emerged between the number of fires and the distribution of different traits considered, with two main axes: on the positive PC2 axis vegetative height and seed mass; and on negative PC1 axis leaf carbon and positive PC1 axis nitrogen content and leaf area. We also showed that vegetative height is positively correlated to the aridity index distribution in the region studied. Synthesis: We analysed the relationships among fire, vegetation and functional traits, at both species and community levels. Altogether, there are highly significant direct relationships between the number of fires and leaf area (negatively) as well as seed mass (positively). For woody communities, wood density is also highly positively significant related to the number of fires. Overall, these findings suggest that fire may have an important impact on the functional response of plant communities, while not apparent when looking at individual species. Further, this research paves new ground to better understand the mechanisms behind trait convergence and the way plant communities respond to different environmental pressures.

Study of Transmission and Haze of Translucent Wood Based on Wood Density and Hyperspectral Analysis of Wood Fabrication

Study of Transmission and Haze of Translucent Wood Based on Wood Density and Hyperspectral Analysis of Wood Fabrication

High-quality genome of Firmiana hainanensis provides insights into the evolution of Malvaceae subfamilies and the mechanism of their wood density formation.

The Malvaceae family, the most diverse family in the order Malvales, consists of nine subfamilies. Within the Firmiana genus of the Sterculioideae subfamily, most species are considered globally vulnerable, yet their genomes remain unexplored. Here, we present a chromosome-level genome assembly for a representative Firmiana species, F. hainanensis, 2n = 40, totaling 1536 Mb. Phylogenomic analysis shows that F. hainanensis and Durio zibethinus have the closest evolutionary relationship, with an estimated divergence time of approximately 21 MYA and distinct polyploidization events in their histories. Evolutionary trajectory analyses indicate that fissions and fusions may play a crucial role in chromosome number variation (2n = 14 to 2n = 96). Analysis of repetitive elements among Malvaceae reveals that the Tekay subfamily (belonging to the Gypsy group) contributes to variation in genome size (ranging from 324 Mb to 1620 Mb). Additionally, genes associated with P450, peroxidase, and microtubules, and thereby related to cell wall biosynthesis, are significantly contracted in F. hainanensis, potentially leading to its lower wood density relative to Hopea hainanensis. Overall, our study provides insights into the evolution of chromosome number, genome size, and the genetic basis of cell wall biosynthesis in Malvaceae species.

Physical and mechanical properties of the stem and branch wood of West African ebony (Diospyros mespiliformis)

This study examines the physical and mechanical properties of the sapwood and heartwood of the stem and branch wood of the West African ebony (Diospyros mespiliformis) to determine if the branch wood can be used for various products. Three mature Diospyros mespiliformis trees with stem diameters at breast height ranging from 50 to 65cm and branch diameters from 25 to 40 cm were purposively selected and felled. Wood samples were prepared to the exact sizes in accordance to the chosen standards, tested, and analysed. The results showed that wood density was insignificantly higher in the stem wood (551 kg/m³) than the branch wood (513 kg/m³). Radially, the heartwood had higher density than the sapwood for both stem wood and branch wood. The Modulus of Elasticity (MOE) was higher in the branch part (7066 MPa) than stem part (1903 MPa), and the sapwood recorded higher MOE for both stem wood and branch wood. Moreover, the Modulus of Rupture (MOR) had a similar result, with the stem part showing a higher average MOR (61 MPa) than the branch part (52 MPa), the sapwood had higher values as compared to its corresponding heartwood. The same trend was observed for the compression strength as well as Janka hardness. In general, it was shown that the branch wood could equally perform well when used as a supplement to the stem wood.

Microstructural properties of Pacific yew as determined with SilviScan

Summary Pacific yew (Taxus brevifolia Nutt.) is a conifer from the northwestern United States with unusually dense and flexible wood. Because the wood of Pacific yew is not used at scale in the commercial industry, there has been no study of radial variation in wood properties or of the microstructural characteristics responsible for its atypical combination of high density and relatively low stiffness. Increment cores (12.5 mm in diameter) were obtained from 15 Pacific yew trees; SilviScan was used to observe patterns of radial variation in density, microfibril angle (MFA), and stiffness in the cores, and these patterns were compared to other conifer species. Observations included unusually dense wood with uncharacteristically low stiffness, a very slow decrease in density from pith to bark unlike any of the typical patterns of radial density variation reported for other conifers in North America, and an MFA that remained constant at its high initial value of approximately 35 degrees throughout the tree’s lifespan. Microstructural properties and macro characteristics were used to explore the ecological niche into which T. brevifolia fits, as it possesses features not shared by any other species of North American conifer.

Modeling the evaluation of methods for determining the basic density of wood in forest species based on data from a neuro-fuzzy inference system

The forestry sector is one of the agribusiness sectors that generates the most wealth for the national economy, as it brings benefits to society, from the wood itself for industries, biomass for energy production, and to the environment, reducing pressure on native forests and the reuse of land degraded by agriculture. In view of this, this study was carried out to predict the different basic densities in tree species under the influence of two factors, nine different tree species in relation to three different density methodologies using the Neuro-Fuzzy System. Tree basic density modeling was carried out using effective species parameters and different calculation methodologies adapted to the Neuro-Fuzzy Inference System (ANFIS). In the ANFIS model, 67% and 33% of the total data were considered as training and test data, respectively. The numbers of pertinence functions were selected 9 for species and 3 for methodologies for the input data. ANFIS training was carried out using the hybrid method. The average R2 determination coefficients were 87.32% and 97.42% for the field and ANFIS models, respectively. The model obtained using ANFIS showed a high accuracy of 4.36%. Compared to the field data, the ANFIS model was highly accurate and can be used to estimate the basic density of the trees in this study.

Green Nanotechnology of Cell Wall Swelling for Nanostructured Transparent Wood of High Optical Performance.

Transparent wood composites provide new functionalities through active additives distributed at the nanoscale. Scalable nanotechnology includes processing where nanoparticles and molecules are brought into the dense wood cell wall. A novel cell wall swelling step through green chemistry is therefore investigated. Sub-zero centigrade NaOH treatment provides extensive cell wall swelling. Cell wall accessibility is vastly increased so that chemicals can readily impregnate the nanostructured cell wall. Transparent wood with a thickness of up to 15mm can therefore be fabricated. The optical transmittance and the attenuation coefficient are improved since the polymer is distributed inside the cell wall as a matrix for the nanoscale cellulose fibrils. The proposed technology paves the way for scalable wood nanoengineering.

Оценка степени обработки бором древесины методом пропитки

Faced with the escalating crisis of global deforestation, including particularly alarming rates in Sri Lanka, researchers have turned their attention to the potential of boronbased preservatives for treating timber. The comprehensive study of the samples has revealed a significant negative correlation between the treatability of timber under pressure and the total area of vessels and wood density. Woods with fewer and smaller vessels are more receptive to boron treatment, making them more suitable for preservation. The study also identified a positive, though somewhat weak, correlation between treatability and the total ray area within the wood, indicating that the internal structure of timber plays a crucial role in its preservation potential. The timber during the research has been categorized based on the depth of boron penetration, with categories ranging from fully penetrated to less than 5 mm. The findings obtained suggest that boron preservatives offer a promising and sustainable alternative to traditional timber treatment methods. By categorizing wood based on the treatability and anatomical properties, we can optimize the treatment processes, thereby maximizing resource utilization and minimizing waste. Thus boron-treated timber could become a cornerstone in the fight against deforestation in future, providing a responsible and environmentally friendly alternative to the untreated wood. In doing so, the research contributes significantly to the preservation of our forests and the overall well-being of our planet, offering a promising trajectory in sustainable forestry practices.

Effects of climate variability on secondary xylem formation and anatomy in fagus sylvatica trees grown in Denmark

ABSTRACT Tree-ring width chronologies of Fagus sylvatica L. have been studied to understand the growth–climate relationship in Denmark, but there is little evidence of a clear climate signal in such tree-ring width data. In this study, tree-ring width chronologies of F. sylvatica trees growing in an even-aged stand in Denmark over the period 1972–2012 were supplemented with wood density and quantitative wood anatomy variables using the SilviScan-3 combined set-up. The effects of moisture availability and temperature variations on xylem features were investigated. Some xylem features showed stronger associations with drought index (DI) and temperature than ring width. Specifically, the September drought was associated with an increased mean area of the individual fibers in the ring formed the following year. Drought in October resulted in a higher density the following year, probably via increased fiber wall thickness and decreased areas of individual vessels. Further, late summer and early autumn warming increased the vessel density in the following year, but drought reduced their cross-sectional area. By dividing tree rings into ten segments, relationships between wood density and DI could be evaluated at the intra-annual level. In the third segment, wood density decreased with previous year December drought, while the April drought increased the wood density of this segment. Together, the results indicated that xylem formation and anatomy in F. sylvatica seem to be linked to moisture availability and temperature, and that dry and warm conditions affect xylem features differently depending on when they occur relative to wood formation.

Difference in summer heatwave-induced damage between desert native and urban greening plants in an arid desert region.

Summer heatwaves have caused a distinct mortality between urban greening and native plants. However, there are insufficient studies revealing the underlying mechanisms. We hypothesized that differentiation in hydraulic traits and their integration cause the varied heatwave-induced damages between the two plant types. To prove it, three desert native species and five urban greening species were selected as the experimental objects. Then, the number of damaged individuals caused by summer heatwaves were investigated based on the 100 individuals for each species. The hydraulic traits (including hydraulic transport, photosynthetic and leaf traits) of 3-5 mature individuals were measured for each species. The comparative analysis (independent sample t test and one-way ANOVA) and the collaborative analysis (Pearson correlation and network analysis) were used to reveal the differences in heatwave-induced damage, hydraulic traits and their integration between urban greening and native plants. Our results showed that the heatwave-induced damage to urban greening plants was larger than that to native species. Water potentials of leaf and branch in pre-dawn and midday, P50, leaf dry matter content, net photosynthetic rate, transpiration rate and stomatal conductance of desert native species were significantly lower than those of urban greening plants (P < 0.05), while twig specific hydraulic conductivity, Huber value, wood density, intrinsic water use efficiency and the specific leaf area showed opposite patterns (P < 0.05). Trait integration of desert native species (0.63) was much higher than greening plants (0.24). Our results indicate that artificial urban greening plants are more susceptible to drought stress caused by heatwaves than native desert species. In the context of global climate change, in order to maintain the stability and function of urban ecosystems in extreme climate, the screening of greening plants should start from the perspective of hydraulics and trait integration, and more native species with strong drought adaptability should be planted.