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Background and Aims Heartwood plays an important role in maintaining the structural integrity of trees. Although its formation has long been thought to be driven solely by internal ageing processes, more recent hypotheses suggest that heartwood formation acts as a regulator of the tree water balance by modulating the quantity of sapwood. Testing both hypotheses would shed light on the potential ecophysiological nature of heartwood formation, a very common process in trees. Methods We measured quantities of heartwood and sapwood, xylem conduits and the width and number of growth rings on 406 stems of Pericopsis elata with ages ranging from 2 to 237 years. A subset of 17 trees with similar ages but varying growth rate were sampled in a shaded (slower-growth) site and a sun-exposed (faster-growth) site. We used regression analysis and structural equation modelling to investigate the dynamics and drivers of heartwood formation. Key Results We found a positive effect of growth rate on the probability of heartwood occurrence, suggesting an earlier heartwood onset in faster-growing stems. After this onset age, heartwood area increased with stem diameter and age. Despite the similar heartwood production per unit stem diameter increment, shaded trees produced heartwood faster than sun-exposed trees. Tree age and hydraulics showed similar direct effects on heartwood and sapwood area of sun-exposed trees, suggesting their mutual role in driving the heartwood dynamics of sun-exposed trees. However, for shaded trees, only tree hydraulics showed a direct effect, suggesting its prominent role over age in driving the heartwood dynamics in limited growing conditions. The positive relationship between growth rate and maximum stomatal conductance supported this conclusion. Conclusions Heartwood area increases as the tree ages, but at a slower rate in trees where water demand is balanced by a sufficient water supply. Our findings suggest that heartwood formation is not only a structural process but also functional. [ABSTRACT FROM AUTHOR]

Summary: Tree stem methane emissions are important components of lowland forest methane budgets. The potential for species‐specific behaviour among co‐occurring lowland trees with contrasting bark characteristics has not been investigated.We compare bark‐mediated methane transport in two common lowland species of contrasting bark characteristics (Melaleuca quinquenervia featuring spongy/layered bark with longitudinally continuous airspaces and Casuarina glauca featuring hard/dense common bark) through several manipulative experiments.First, the progressive cutting through M. quinquenervia bark layers caused exponential increases in methane fluxes (c. 3 orders of magnitude); however, sapwood‐only fluxes were lower, suggesting that upward/axial methane transport occurs between bark layers. Second, concentrated methane pulse‐injections into exposed M. quinquenervia bark, revealed rapid axial methane transport rates (1.42 mm s−1), which were further supported through laboratory‐simulated experiments (1.41 mm s−1). Laboratory‐simulated radial CH4 diffusion rates (through bark) were c. 20‐times slower. Finally, girdling M. quinquenervia stems caused a near‐instantaneous decrease in methane flux immediately above the cut. By contrast, girdling C. glauca displayed persistent, though diminished, methane fluxes.Overall, the experiments revealed evidence for rapid 'between‐bark' methane transport independent from the transpiration stream in M. quinquenervia, which facilitates diffusive axial transport from the rhizosphere and/or sapwood sources. This contrasts with the slower, radial 'through‐bark' diffusive‐dominated gas transportation in C. glauca. See also the Commentary on this article by Ward & Megonigal, 242: 5–7. [ABSTRACT FROM AUTHOR]

Phenol-formaldehyde (PF) resins can be impregnated and cured in situ to improve the woods dimensional stability and decay resistance. In search of renewable alternatives, the substitution of phenol by lignin cleavage products (LCP) has been discussed. However, the different chemical nature may affect the performance of the resin against fungal decay, formaldehyde emission, and equilibrium moisture content. In this study, 30 % (w/w) of the phenol in PF resins were substituted by LCP obtained from microwave-assisted pyrolysis. Scots pine sapwood was modified with the resin. The decay resistance against Rhodonia placenta, Gloeophyllum trabeum, and Trametes versicolor was determined. Additionally, effects of specimen organisation within the Petri dish, different substrates, length of leaching, and type of inoculum were studied. Further, the materials water vapor sorption properties and formaldehyde emission were determined. All modifications effectively reduced fungal decay. With 10 % weight percent gain (WPG), initial decay was detected, while 20 % WPG and 30 % WPG provided efficient protection. The substitution of phenol increases the formaldehyde emission. While further reduction in formaldehyde in the resin admixture or formaldehyde scavengers may be required, the method described herein can be used to partly replace fossil-based phenol, while maintaining good fungal resistance. [ABSTRACT FROM AUTHOR]

Carbon fraction (CF) of trees is essential for quantifying forest carbon (C) stocks. Considerable attention has been paid to CF variations at various levels with the exception of inter- and intra-growth rings. Herein, the inter- and intra-growth ring variation of CF in Pinus tabuliformis was investigated. Elemental analysis was performed to obtain CF values of the earlywood and latewood in each growth ring of the xylem. Patterns of CF variation at the growth ring level were evaluated using mixed-effect models. The results showed that latewood CF, 50.6 %, was significantly higher than earlywood CF, 49.9 % (p < 0.01). In particular, inter-growth ring variations of CF differed between heartwood and sapwood, as well as between juvenile wood and mature wood. CF values decreased nonlinearly with cambium age toward the heartwood or juvenile wood, with estimated least-squares means of 50.4 % and 51.8 %, respectively. While CF values were almost unaltered in sapwood, and slightly decreased in mature wood, with estimated least-squares means of 50.0 % and 50.2 %, respectively. It indicates that patterns of CF variation between juvenile wood and mature wood are important to estimate the C stock of P. tabuliformis. This research provides insights into C uptake dynamics to support forest management and wood utilization. [ABSTRACT FROM AUTHOR]

Wood pellets produced from fresh sawdust can form and release uncontrolled gases during bulk storage, a tendency referred to as off-gassing. This study investigated the off-gassing tendencies of Scots pine wood pellets made from separated sapwood and heartwood sawdust. The effects of drying temperature, raw material storage, as well as varying proportions of sapwood and heartwood were also investigated. There was a strong linear correlation between off-gassing and sapwood content, with correlation coefficient (R) values greater than 0.9 at p < 0.001 for all the off-gases. An increase in sapwood content of the feedstock led to a significant increase in off-gassing of CO2, CO, and CH4, and O2 consumption. The drying temperature of the raw material had a significant effect on off-gassing of both sapwood (F(8, 26) = 51.32, p < 0.05) and heartwood (F(8, 26) = 334.1, p < 0.05) pellets. Increasing the drying temperature for heartwood resulted in increased off-gassing, while for sapwood, the off-gassing reduced. Storage of sapwood raw material before pelletization reduced the off-gassing of wood pellets, whereas for heartwood, it had no significant impact. Based on the results, it is suggested that a biological process, in combination with the chemical oxidation of fatty acids, lay behind the off-gassing of wood pellets. [ABSTRACT FROM AUTHOR]

Global forests are increasingly being threatened by altered climatic conditions and increased attacks by pests and pathogens. The complex ecological interactions among pathogens, microbial communities, tree hosts and the environment are important drivers of forest dynamics. Little is known about the ecology of forest pathology and related microbial communities in temperate forests of the southern hemisphere. In this study, we used next‐generation sequencing to characterize sapwood‐inhabiting fungal communities in North Patagonian Nothofagus forests and assessed patterns of diversity of taxa and ecological guilds across climatic, site and host variables (health condition and compartment) as a contribution to Nothofagus autecology. The diversity patterns inferred through the metabarcoding analysis were similar to those obtained through culture‐dependent approaches. However, we detected additional heterogeneity and greater richness with culture‐free methods. Host species was the strongest driver of fungal community structure and composition, while host health status was the weakest. The relative impacts of site, season, plant compartment and health status were different for each tree species; these differences can be interpreted as a matter of water availability. For Nothofagus dombeyi, which is distributed across a wide range of climatic conditions, site was the strongest driver of community composition. The microbiome of N. pumilio varied more with season and temperature, a relevant factor for forest conservation in the present climate change scenario. Both species carry a number of potential fungal pathogens in their sapwood, whether they exhibit symptoms or not. Our results provide insight into the diversity of fungi associated with the complex pathobiome of the dominant Nothofagus species in southern South America. [ABSTRACT FROM AUTHOR]

Water stored in trunk sapwood is vital for the canopy to maintain its physiological function under high transpiration demands. Little is known regarding the anatomical properties that contribute to the hydraulic capacitance of tree trunks and whether trunk capacitance is correlated with the hydraulic and gas exchange traits of canopy branches. We examined sapwood capacitance, xylem anatomical characteristics of tree trunks, embolism resistance, the minimal xylem water potential of canopy branches, leaf photosynthesis and stomatal conductance in 22 species from a tropical seasonal rainforest and savanna. The results showed that the mean trunk sapwood capacitance did not differ between the two biomes. Capacitance was closely related to the fiber lumen fraction and fiber wall reinforcement and not to the axial and ray parenchyma fractions. Additionally, it was positively correlated with the theoretical hydraulic conductivity of a trunk and the specific hydraulic conductivity of branches, and showed a trade-off with branch embolism resistance. Species with a high trunk sapwood capacitance maintained less negative canopy water potentials in the dry season, but higher leaf photosynthetic rates and stomatal conductance in the wet season. This study provides a functional link among trunk sapwood capacitance, xylem anatomy, canopy hydraulics and photosynthesis in tropical trees. [ABSTRACT FROM AUTHOR]

In this study, pine sapwood was first impregnated with micronized copper (Cu) solution at concentrations of 5 and 10%, the samples then dried and impregnated with ethyl palmitate as a bio-based phase change material (BPCM). The leakage test showed slightly less leakage in this scenario compare to controls without copper. The mould test showed using copper solution, significattly improves the resistance of the composites to mould growth. Thermal tests showed using BPCM improves thermal conductivity and thermal mass of the composites, enabling them to store and release energy within the temperature range of 20-25°C. It is observed that the copper did not improve thermal conductivity, and 5% copper showed the best performance in thermal mass improvement. [ABSTRACT FROM AUTHOR]

Objectives: Molecular cues linked to heartwood formation open new (complementary) perspectives to genetic breeding programs of Douglas-fir, a tree species largely cultivated in Europe for the natural durability and civil engineering properties of its wood. Data description: RNAs from a single genotype of Douglas-fir, extracted from three distinct wood zones (outer sapwood, inner sapwood and transition zone) at four vegetative seasons to generate an extensive RNA-seq dataset used to apprehend the in-wood dynamic and seasonality of heartwood formation in this hardwood model species. Previously published data collected on somatic embryos of the same genotype could be merged with the present dataset to upgrade grade the Douglas-fir reference transcriptome. [ABSTRACT FROM AUTHOR]

Luminescent lanthanide-doped phosphates have never been introduced as potential materials for wood functionalization. Wood–ceramic composites (WCC) may enable the extensive use of wood in construction due to different functionalization. Hence, this work proposes the inorganic GdPO 4 ·H 2 O:Eu3+ compound as an alternative and innovative method to increase wood chemical resistance and confer new optical properties. Scots pine (Pinus sylvestris L.) sapwood – ceramic composite was obtained through in situ hydrothermal synthesis and compared with the untreated sapwood specimens. The enhanced characteristics of the WCC samples were demonstrated using scanning electron microscopy (SEM), x-ray computed micro-tomography (μCT), and thermogravimetric (TG) analysis. Optical properties were determined by luminescence analysis. [ABSTRACT FROM AUTHOR]

Summary: Shifts in the age or turnover time of non‐structural carbohydrates (NSC) may underlie changes in tree growth under long‐term increases in drought stress associated with climate change. But NSC responses to drought are challenging to quantify, due in part to large NSC stores in trees and subsequently long response times of NSC to climate variation.We measured NSC age (Δ14C) along with a suite of ecophysiological metrics in Pinus edulis trees experiencing either extreme short‐term drought (−90% ambient precipitation plot, 2020–2021) or a decade of severe drought (−45% plot, 2010–2021). We tested the hypothesis that carbon starvation – consumption exceeding synthesis and storage – increases the age of sapwood NSC.One year of extreme drought had no impact on NSC pool size or age, despite significant reductions in predawn water potential, photosynthetic rates/capacity, and twig and needle growth. By contrast, long‐term drought halved the age of the sapwood NSC pool, coupled with reductions in sapwood starch concentrations (−75%), basal area increment (−39%), and bole respiration rates (−28%).Our results suggest carbon starvation takes time, as tree carbon reserves appear resilient to extreme disturbance in the short term. However, after a decade of drought, trees apparently consumed old stored NSC to support metabolism. [ABSTRACT FROM AUTHOR]

The size-related xylem adjustments required to maintain a constant leaf-specific sapwood conductance (K LEAF) with increasing height (H) are still under discussion. Alternative hypotheses are that: (i) the conduit hydraulic diameter (Dh) at any position in the stem and/or (ii) the number of sapwood rings at stem base (NSWr) increase with H. In addition, (iii) reduced stem elongation (Δ H) increases the tip-to-base conductance through inner xylem rings, thus possibly the NSWr contributing to K LEAF. A detailed stem analysis showed that Dh increased with the distance from the ring apex (DCA) in all rings of a Picea abies and a Fagus sylvatica tree. Net of DCA effect, Dh did not increase with H. Using sapwood traits from a global dataset, NSWr increased with H , decreased with Δ H , and the mean sapwood ring width (SWrw) increased with Δ H. A numerical model based on anatomical patterns predicted the effects of H and Δ H on the conductance of inner xylem rings. Our results suggest that the sapwood/heartwood transition depends on both H and Δ H , and is set when the carbon allocation to maintenance respiration of living cells in inner sapwood rings produces a lower gain in total conductance than investing the same carbon in new vascular conduits. [ABSTRACT FROM AUTHOR]

This study investigated the effect of high-intensity microwave (HIMW) treatment on the chemistry of sapwood and heartwood of radiata pine. The wet chemical method, X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) were utilized to assess and evaluate the effect of different microwave energy densities (0, 60, 80, and 100 kWh/m3) on the chemical composition, chemical structure, and cellulose crystallinity of both sapwood and heartwood. The results indicated that the greatest changes in the relative content of lignin and cellulose were observed at a microwave energy density of 80 kWh/m3. Furthermore, XPS analysis demonstrated a decrease in the O/C ratio as the microwave energy density increased. When the energy density of microwave reached 100 kWh/m3, the O/C ratio of sapwood and heartwood decreased by 10.2% and 19.6%, respectively. At the same time, no notable changes were detected in the FTIR spectra of the microwave-treated samples. Due to the recrystallization of cellulose and the presence of aromatic C=O groups, which could be linked to the rise in lignin content, there were slight variations in several absorption intensities and peak positions, such as O–H groups. As microwave energy density increased, both the crystallinity index (CI) and cellulose crystal width (D200) of HIMW-treated samples increased accordingly. The findings indicated that the chemistry of radiate pine's sapwood and heartwood was affected differently by the microwave treatment. Notably, the heartwood exhibited a more pronounced impact compared to the sapwood. [ABSTRACT FROM AUTHOR]

Summary: Nutrient allocation is central to understanding plant ecological strategies and forest roles in biogeochemical cycles. Thought to be mainly driven by environmental conditions, nutrient allocation to woody organs, especially to living tissues, is poorly understood.To examine the role of differences in living tissues (sapwood, SW, vs inner bark, IB), organs, ecological strategies, and environmental conditions in driving nutrient allocation and scaling in woody plants, we quantified nitrogen and phosphorus in main stems and coarse roots of 45 species from three tropical ecosystems with contrasting precipitation, fire regime, and soil nutrients.Nutrient concentration variation was mostly explained by differences between IB and SW, followed by differences between species and, in the case of phosphorus, soil nutrient availability. IB nutrient concentrations were four times those of SW, with root tissues having slightly higher concentrations than stem tissues. Scaling between IB and SW, and between stems and roots, was generally isometric. In cross‐sections, IB contributed half of total nutrients in roots and a third in stems.Our results highlight the important role of IB and SW for nutrient storage, the coordination in nutrient allocation across tissues and organs, and the need to differentiate between IB and SW to understand plant nutrient allocation. [ABSTRACT FROM AUTHOR]

Catchment-scale transpiration is commonly determined by the use of sap-flow sensors, and its quantification, which is critical for water and forest management, relies crucially on the total catchment's sapwood area (As). Species-specific allometric relationships between the trees As and the trees diameter at breast height (DBH) are widely used for determining stand or catchment As. However, substantial differences between studies challenge the robustness of these relationships between sites displaying various topographical and environmental characteristics. Our objectives for this study are to compare the parameters of these relationships between species of the Quercus genus from different sites across the globe and to test the role of topographical factors on the As-DBH relationship in Quercus petraea. Using 145 trees sampled within a 0.455 km2 catchment, we found that topography (slope, flow accumulation, aspect, curvature, and topographic wetness index) does not modulate the As-DBH relationship in Q. petraea, within our catchment. We compared our curve parameters with those from 16 studies on oak trees and found that the As-DBH relationship is not only species-specific, but depends on the site's conditions. The use of species-specific parameters from other sites may lead to more than 100% difference in the calculation of As, and therefore in forest transpiration. In the light of these results, we recommend building site- and species-specific As-DBH relationships for determining stand or catchment transpiration, using a minimum of nine, randomly sampled trees, and different methods and azimuthal directions for determining sapwood depth. [ABSTRACT FROM AUTHOR]

Radiocontaminated Cryptomeria japonica from Iitate village in Fukushima was analyzed in terms of the bark, sapwood and heartwood. Both 134Cs and 137Cs activities were confirmed in these wood components. The sum of 134Cs and 137Cs activities was the highest in the bark, the lowest in the sapwood and that of the heartwood in between. Although the holocellulose isolated from the bark was contaminated by 134Cs and 137Cs activities, these radiocesiums were not detected in the holocelluloses from sapwood and heartwood. Similar results were obtained for dioxane lignins isolated from sapwood and heartwood. An examination of the FTIR spectra of holocelluloses and dioxane lignins from the bark, sapwood and heartwood of C. japonica originated from radiocontaminated Iitate, and radiocontamination-free Fuji areas revealed that the structures of the constitutions of the former wood were not altered by the radiocontamination. Furthermore, the FTIR spectra of the outer bark and inner bark holocelluloses from the artifically 137Cs-impregnated Fuji tree were similar to those of the outer bark and inner bark holocelluloses of the radiocontaminated Iitate tree. [ABSTRACT FROM AUTHOR]

The paper presents the experimental results concerning the amount of extractable substances and the color changes determined by the reaction of the tannins contained in wood with iron. Tests were performed comparatively with sapwood and heartwood samples of two Quercus species, namely Turkey oak (Quercus cerris L.) and sessile oak (Quercus petraea (Matt.) Liebl.). The findings show that Turkey oak sapwood has an unexpectedly high amount of extractable substances, higher than the heartwood of the same species. This result was obtained with three extraction methods (cold water, hot water, and NaOH 1% solution). The FTIR investigation of the extracts impregnated on quantitative filter paper seems to confirm these results. Visual assessment and color measurements after applying FeCl3 highlight that both oak species are prone to staining in contact with iron due to their tannin content. The values of the total colour difference between the state and after the reaction with FeCl3, lower fer for Turkey oak compared to sessile oak, correlate with a lower extractive content of this wood species. [ABSTRACT FROM AUTHOR]

Quercus cerris (Turkey oak) has been categorised as a droughttolerant species because it can survive with rainfall below 400 mm/year, and it usually develops deep and penetrating taproots. This characteristic suggests that Turkey oak is a survival candidate species to the future environment with the predicted climate scenarios in Hungary. Potentially, Turkey oak could support a sustainable supply of timber to the Hungarian wood industry in the future, as the aesthetic value is similar to that of noble oaks. The objectives of the study are to determine 1; the selected micro-level wood properties (wood tissue characteristics) and 2; the selected macrolevel wood properties (tree-ring width, sapwood-heartwood ratio) for Turkey oak from two different sites. The heartwood portion for all trees constituted 67-82% of cross-diameter. The growth-ring width decreased from pith to bark. The annual rings in the sapwood had a width value range of 1000 to 1600 µm; in heartwood 1600 to 2500 µm; in juvenile wood 2400 to 3300 µm. Soil quality and stand composition had a significant effect on growth-ring width. Fibre length ranged from 800.03 to 1305.59 μm, whereas fibre-wall thickness varied between 11.73 and 18.51 μm, with soil quality and species composition having highly significant influence. The earlywood parts of the growth rings had a vessel diameter range of 274.62-401.54 μm, whereas the latewood portion ranged from 46.50 to 190.08 μm. Overall, stand composition was a major source of variation in the properties studied. [ABSTRACT FROM AUTHOR]

In this paper, the natural durability of commercial wood (beech wood) was studied by measuring its water exclusion efficacy and durability against fungi. This information was utilized in the Meyer-Veltrup model to calculate the resistance dose. The results showed that Fagus orientalis (Lipsky) heartwood and sapwood were less durable (DC 4-5). After one hour of immersion, the water uptake in F. orientalis sapwood was 19%, slightly more than that determined with F. orientalis heartwood (18.9%). Water immersion after 24 h was highest for F. orientalis sapwood (45.4%), followed by F. orientalis heartwood (40.9%). Up to 54.2% median MLF on F. orientalis heartwood and up to 61.1% median MLF on F. orientalis sapwood were attributed to the white fungus T. versicolor. In contrast, the lowest median MLF was caused by F. orientalis heartwood and sapwood by the white fungus H. fragiforme. 35.4% median MLF on F. orientalis was caused by terrestrial microcosms. Based on the resistance model, the first signs of fungal decay on F. orientalis heartwood and sapwood wood will develop after 312 and 294 days of favorable conditions, respectively. [ABSTRACT FROM AUTHOR]

The objective of this research was to establish comparatively some relevant features of Turkey oak and sessile oak wood, in order to better understand the drying behavior of these species. The analyzed samples were obtained from freshly harvested trees of the same age, originating from the Southern Sub-Carpathians. The microscopic analysis revealed that Turkey oak has larger earlywood pores than sessile oak. In heartwood, they are partly filled with tyloses for both species. The macroscopic analysis showed that Turkey oak wood has a much lower proportion of heartwood (only 50%) compared to sessile oak (90%). The comparative FTIR analysis of the two species showed similar qualitative chemical composition, but also some differences between sapwood and heartwood regarding the relative proportion of the main constituents, and very likely in the structure of lignin. High amounts of extractives were found in Turkey oak sapwood (5.34% in cold water, 7.77% in hot water, and 21.60% in NaOH 1%), close to the values obtained in sessile oak heartwood. The research also revealed that the Turkey oak sapwood and heartwood have statistically similar values of oven-dry density, shrinkage coefficient, fiber saturation point, while in sessile oak, the values are clearly higher in the heartwood. [ABSTRACT FROM AUTHOR]

Differences in the density of beech wood in an absolutely dry state in individual zones: sapwood, mature wood, and false heartwood through a cross-section of the trunk are presented in the paper. The wood density of individual zones was determined with a digital density meter. Experimental measurements and subsequent statistical processing of the measured values showed that the density of beech samples with a false heartwood has a decreasing tendency through the cross-section of the trunk from the center of the trunk to the edge. The highest density ρ0 = 703.8 ± 36.1 kg.m-3 was observed in the dry state of beech samples with false heartwood. The density of mature wood in the absolutely dry state was 5.5% less compared to false heartwood, and the density of sapwood was 13.6 % less compared to false heartwood. The proven differences in the density of absolutely dry beech wood in the individual zones do not exceed the natural range of the density values of the beech wood (Fagus sylvatica L.) mentioned in the professional literature. For the above reason, it is not necessary to take into account the changes in the density of the wood through the cross-section of the trunk in common technical applications. The presented data contribute to the objectification of information about the properties of beech wood and enrich current knowledge. [ABSTRACT FROM AUTHOR]

The height, diameter, and leaf area of trees influence the anatomical structures because rapid growth requires maintenance of the water conduction in sapwood, despite environmental variations that may limit water supply. Our objective was to evaluate the influence of water availability conditions on the soil in humid and dry sites, on the percentage of sapwood along the trunk, and on the hydraulic properties of the wood of eucalyptus clones. The experimental plantings were carried out in Brazil in humid and dry sites. Six-year-old E. urophylla and E. grandis × E. camaldulensis clones were evaluated under 100% water (W) at each site considering local precipitation and 33% rainfall exclusion (WE) conditions. The wood was evaluated for heartwood and sapwood percentage, apparent sapwood density, diameter, wall thickness and vessel area, potential hydraulic conductivity, and Huber value. Rainfall exclusion at the dry site promoted an increase of 9% of sapwood when compared to the humid site, with an impact on diameter, area, wall thickness and vessel composition index, and lower Huber value for E. grandis × E. camaldulensis wood. The rainfall exclusion increased the sapwood percentage and reduced the growth of E. urophylla. E. grandis × E. camaldulensis had a higher sapwood apparent density at the dry site, while E. urophylla had a higher density at the humid site. The genetic diversity of the clones was expressed in the tree growth and in the sapwood content and was modified by humid and dry sites, which demonstrates different rusticity levels of the clones. [ABSTRACT FROM AUTHOR]

Acacia melanoxylon (blackwood) is a valuable wood with excellent-quality heartwood extensively utilized worldwide. The main aim of this study was to confirm the horizontal and vertical variation and provide estimated values of genetic gains and clonal repeatabilities for improving breeding program of A. melanoxylon. Six blackwood clones at 10 years old were analyzed in Heyuan and Baise cities in China. Stem trunk analysis was conducted for sample trees to explore the differences between heartwood and sapwood. The heartwood radius (HR), heartwood area (HA), and heartwood volume (HV) in heartwood properties decreased as tree height (H) in growth traits increased, and the HV = 1.2502 DBH (diameter at breast height)1.7009 model can accurately estimate the heartwood volume. Furthermore, G × E analysis showed that the heritabilities of the eleven indices, including DBH, DGH (diameter at ground height), H, HR, SW (sapwood width), BT (bark thickness), HA, SA (sapwood area), HV, HRP (heartwood radius percentage), HAP (heartwood area percentage), and HVP (heartwood volume percentage) were between 0.94 and 0.99, and repeatabilities of the eleven indices were between 0.74 and 0.91. Clonal repeatability of DBH (0.91), DGH (0.88), and H (0.90) in growth traits, HR (0.90), HVP (0.90), and HV (0.88) in heartwood properties were slightly higher than for SA (0.74), SW (0.75), HAP (0.75), HRP (0.75), and HVP (0.75). These data also implied that the growth characteristics of heartwood and sapwood of blackwood clones were less affected by the environment and had substantial heritability. [ABSTRACT FROM AUTHOR]

Understanding wood cell wall pore geometry and distribution is the basis for studying its macroscopic properties. This research investigated the pore fractal dimension using the pore size distribution of selected softwoods and hardwoods. Nitrogen gas analyzer was used to study the detailed structural parameters of wood pore size distributions and use as a raw data to assess their fractal dimension. The results revealed significant variability in pore size distribution, porosity, pore volume, specific surface area, and fractal dimension. The cell wall pore size distribution ranged from 1.41 (minimum) to 442 nm (maximum). Western red cedar heartwood and sapwood show a higher and lower number of micropores, respectively, in the wood cell wall. The results also showed that the fractal dimensions of the cell wall pore spaces of wood vary between 2.92 and 2.97. There was no significant difference in fractal dimensions between wood types and species. [ABSTRACT FROM AUTHOR]

The effects of pressurized hot water extraction (HWE) treatment on the mould resistance of wood have not been extensively investigated yet. The activity of the mould fungi is dependent on the availability of nutrients. Therefore, the soluble degradation products produced during HWE treatment could affect the wood's susceptibility to mould growth. Scots pine (Pinus sylvestris L.) sapwood specimens were treated with HWE at 140 °C for 1–5 h. Afterwards, the degradation products were either removed via leaching or the wood was dried without applying the leaching procedure. The surface layer (1.5 mm) was removed from half of the leached and non-leached specimens. The resistance of the specimens against mould growth was tested in an incubation chamber. HWE treated wood showed a higher susceptibility to mould growth when it was neither leached nor subjected to surface removal. The susceptibility of wood to mould fungi depended on the availability of hemicellulose-based degradation products produced during HWE treatment. These degradation products were removable via a leaching procedure, but also by removing the outermost layer of the wood. The results show the relevance of removing HWE degradation products located on the wood surface in improving resistance against mould growth. [ABSTRACT FROM AUTHOR]

The sapwood of Japanese cedar ( Cryptomeria japonica D. Don ) was decayed by the brown-rot fungus Fomitopsis palustris under bright and dark conditions. Scanning electron microscopy revealed the presence of mycelia inside the wood even after 1 week from the start of fungal exposure. Moreover, holes were observed in the torus after fungal exposure. Ruthenium red staining revealed that the pectin in pits was largely absent for 3 weeks. These events occurred before the mass loss of wood samples was confirmed at the early stage. Moreover, Fp PG28A was more highly expressed at the hyphal front on a pectin-containing medium under dark conditions compared with bright conditions. This up-regulation under dark conditions indicated that the pectin decomposition ability was promoted inside the wood where light could not reach. In conclusion, we suggest that the brown-rot fungus completed its hyphal expansion within the wood via pectin decomposition in pits before holocellulose decomposition. [ABSTRACT FROM AUTHOR]

This study identified elements in a simple homemade gambus from a local crafter using a scientific approach. The gambus was made from geronggang wood (Cratoxylum arborescens), a light Malaysian hardwood with pink sapwood, distinct from the heartwood with brick-red or deep pink. The sound was processed to generate fast Fourier transform (FFT) and time-frequency analysis (TFA) using PicoScope and Adobe Audition software, respectively. The gambus A 1st string (note C4#) displayed a harmonic overtone at the 1st and 2nd octave. The 2nd string (note A3) showed harmonic overtone at the 1st, 2nd, and 3rd octave. The 3rd string (note D3#) showed a significant fundamental peak and harmonic overtone at the 1st, 2nd, 3rd, 4th, and 5th octave. The 4th string (note A2#) displayed consistent harmonic overtones at the 1st, 2nd, 3rd, 4th, and 5th octave. The 5th string (note E2) had a harmonic overtone at the 5th octave. Gambus A showed an inconsistent signal in the 6th string (note D2#) with inharmonic overtone at 3.35th and 6.79th overtones. The gambus A 1st to 6th strings are C4#, A3, D3#, A2#, E2, and D2#, respectively. The gambus B 1st to 6th strings are C4, G3, D3, A3, E3, and B2, respectively. [ABSTRACT FROM AUTHOR]

Timber from plantation forests dominantly contains sapwood and a high percentage of juvenile wood susceptible to termite attack. The resistance of wood against termite attack was found to be enhanced by smoke treatment. The current study investigated the effectiveness of preservatives developed based on chemically-smoke compound on three tropical fast-growing tree species against termite attack. The preservatives formulations A, B, C and D were developed using different compositions of acidic, phenolic, benzene-derivative and alcoholic compound. The wood species selected were from gmelina (Gmelina arborea), jabon (Anthocephalus cadamba) and rubber wood (Hevea brasiliensis). The test was conducted in a laboratory according to the Indonesian standard SNI 7207-2014 using subterranean termite (Coptotermes curvignathus). The results showed that after the preservation process the wood colour which was previously light bright, red and yellow colour turned to darker shades. The untreated woods had poor resistant to subterranean termite attack with an average class of 4.5. In contrast, the preserved woods had moderate resistance with an average or enhanced class of 3.3 or 1.2, respectively. The formulations A, B, C and D were not significantly different with formulation D showed the best results in wood resistance. Therefore, these formulae could be incorporated with other types of chemicals similar to the compounds contained in the wood smoke to produce a more effective preservative for better enhancement of wood resistance. [ABSTRACT FROM AUTHOR]

Stored water in inner tissues influences the plant water economy, which might be particularly relevant for trees facing increasing dry conditions due to climate change. We studied the water storage in the inner bark and the sapwood of Araucaria araucana (Molina) K. Koch. This species has an extremely thick inner bark and thus it can be used as a model system to assess the impact of internal water storage on plant water balance. Specifically, we analyzed the water circulation pathways in and out of the elastic water storages by using simultaneously frequency domain moisture sensors and dendrometers inserted in the inner bark and in the sapwood, and sap flow determinations during the dry season. The daily patterns of water content and expansion and contraction of the stem tissues were similar to the sap flow pattern. The whole-stem water content and diameter increased in the morning and decreased in the afternoon, contrary to the typical pattern observed in most tree species. An osmotic gradient favoring the water influx from sapwood to inner bark was observed in the morning. There were no lags in the onset of sap flow between different stem heights at the time that recharge of reservoirs occurred. Sap flow at 6 m height was higher than basal sap flow in the afternoon, when the sapwood water content started to decline followed by the water content of the inner bark. Inner bark and sapwood contributed 5–11% to total daily transpiration, allowing the maintenance of high water potentials in the dry season. Our results suggest that the stored water in the stems, the atypical dynamic of recharge and discharge of water from reservoirs and the high tissue capacitance may make an important contribution to the survival of A. araucana during drought periods by maintaining the water balance. [ABSTRACT FROM AUTHOR]

Hydraulic architecture refers to the different morphological structures and water transport strategies acquired during the long-term evolution of plants. In this study, Chinese fir, an important commercial forest species in southern China, was examined, and hydraulic architecture characteristics with respect to ramification rate, canopy height, and ramification direction were studied. The results showed that changes in hydraulic architecture parameters of Chinese fir had pronounced rank effects; the hydraulic conductivity and leaf-specific conductivity were in the following order: main stem＞primary lateral branches＞secondary lateral branches; leaf-specific conductivity and Huber values were higher in primary than in secondary lateral branches. Hydraulic architecture parameters at different ramification rates were significantly affected by canopy height. Hydraulic conductivity and specific conductivity of the main stem decreased significantly with increasing canopy height, and the Huber value of the main stem increased significantly with increasing canopy height. Hydraulic conductivity and specific conductivity of primary and secondary lateral branches were the highest in the middle canopy, leaf-specific conductivity of the primary lateral branches decreased significantly with increasing canopy height, and leaf-specific conductivity of secondary lateral branches was the highest in the middle canopy. With regard to different ramification directions, hydraulic conductivity, specific conductivity, and leaf-specific conductivity of primary and secondary lateral branches were generally higher in the south and west directions than in the north and east directions. Correlation analyses showed that hydraulic conductivity at different ramification rates was significantly positively（P＜0.01） correlated with the total diameter, sapwood cross-sectional area, and leaf dry weight; specific conductivity of the main stem was significantly positively（P＜0.05） correlated with these factors, whereas the specific conductivity of primary and secondary lateral branches produced a negative correlation with them. Thus, the smaller the diameter of high-level branches of Chinese fir, the lower is the water transport ability. This hydraulic grade effect is beneficial to sacrificing inferior branches in order to maintain the water supply of superior branches when Chinese fir experience drought stress, which is an important adaption to drought acquired during long-term evolution. This study is of great significance for the breeding of drought-tolerant Chinese fir and sustainable plantation management [ABSTRACT FROM AUTHOR]

The objective of the present study was the determination of the extractives, acidity and ash content of three different provenances of Cupressus semprevirens wood. The specimens were collected from the sapwood, heartwood, bark and needles of the trees. The quantitative determination of the extractions was performed with two different solvents, water and ethanol. The results showed no significant differences among the three provenances (P1, P2 and P3), except for the oldest, which also had the highest extract content, a fact that is attributed to the growth of the trees without competition. Furthermore, the needles and the bark, had, in all cases, the highest ash content, while heartwood appeared to have higher contents of extractives, compared to sapwood. [ABSTRACT FROM AUTHOR]

A single Norway spruce tree (Picea abies) was manually fractionated into heartwood, sapwood, juvenile wood and branches. These fractions were chemically pulped, individually, in laboratory scale. The pulps were characterized and investigated in relation to dewatering behavior and sheet strength properties. An unbleached and unbeaten commercial kraft pulp from softwood fibers was used as a reference, and the fractionated pulps were within the same range in all tested properties. The fractionated pulps were then compared with each other, and fiber characteristics were used to explain differences in dewatering and strength. Heartwood pulp results in stronger and stiffer papers that are harder to dewater. Sapwood pulp gives more open network structures resulting in easy dewatering and high air permeance, although with lower strength properties compared to heartwood. Pulp from Juvenile wood gives s quite strong but brittle sheets, with efficient dewatering. Pulp from branches gives paper sheets with efficient dewatering, air permeance and relatively high elongation of break but lower strength. The results show that there is definitely potential for utilizing more parts of the trees for pulp and paper making, especially when tailoring the raw material origins after preferred paper properties. [ABSTRACT FROM AUTHOR]

The purpose of this study was to characterize and quantify the chemical constituents of heartwood and sapwood of Dalbergia oliveri extract in order to investigate the chemical components that determine the formation of heartwood's color. In this work, the types of pigments in heartwood and sapwood extract were analyzed using UV-Visible (UV) Spectrophotometer, and the main pigment components of heartwood and sapwood extract were identified and quantified using ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS). The results showed that the difference in content of the main components between heartwood and sapwood of Dalbergia oliveri was slight, and the lignin structure between heartwood and sapwood is basically identical; flavonoid pigments were found to be the primary chromophoric components of heartwood and sapwood extract. However, a total of 21 flavonoids were identified in heartwood and sapwood, of which the unique substances to heartwood were vitexin, isorhamnetin, and pelargonidin, and the content of isoliquiritigenin, formononetin, and biochanin A were 253, 37, and 583 times higher in the heartwood than in the sapwood, respectively, which could be the main pigment components affecting the significant color difference between heartwood and sapwood of Dalbergia oliveri. These results will provide a foundation for revealing the underlying mechanism of color difference between heartwood and sapwood and provide a theoretical basis for wood coloring. [ABSTRACT FROM AUTHOR]

Teak wood has chemical compounds that can be used for pharmaceutical and textile industries, in addition, this compounds are related to resistance to biodeterioration, color and modification processes. Heartwood and sapwood of T. grandis (teak), 15 years-old, were characterized by Py-CG/MS analysis and syringyl (S)/guaiacyl (G) ratio was evaluated. Heartwood and sapwood were pyrolyzed at 550 °C and 62 and 51 compounds were identified from them, respectively. The acetic acid (10%) and levoglucosan (26.65%) were the most abundant compound in the sapwood and heartwood, respectively. The high acetic acid content enhances the use of teak wood to production of artificial essences for perfumery, paints, dyes. While levoglucosan can be used in the manufacture of epoxy resins, antiparasitic and insecticides. The organic compounds identified include 2-methylanthraquinone as one of the main component responsible for the resistance of the teak wood to biological factors (fungi and termites). The syringyl (S)/guaiacyl (G) ratio of heartwood and sapwood was 0.51 and 0.50, respectively. [ABSTRACT FROM AUTHOR]

Estimates of tree heartwood and sapwood profiles are important in the pulp industry and for dynamic vegetation models, in which they determine tree biomechanical stability and hydraulic conductivity. Several phenomenological models of stem profiles have been developed for this purpose, based on assumptions on how tree crown and foliage distributions change over time. Here, we derive estimates of tree profiles by synthesizing a simple pipe model theory of plant form with a recently developed theory of branch thinning that from simple assumptions quantifies discarded branches and leaves. This allows us to develop a new trunk model of tree profiles from breast height up to the top of the tree. We postulate that leaves that are currently on the tree are connected by sapwood pipes, while pipes that previously connected discarded leaves or branches form the heartwood. By assuming that a fixed fraction of all pipes remain on the trunk after a branching event, as the trunk is traversed from the root system to the tips, this allows us to quantify trunk heartwood and sapwood profiles. We test the trunk model performance on empirical data from five tree species across three continents. We find that the trunk model accurately describes heartwood and sapwood profiles of all tested tree species (calibration; R 2: 84–99%). Furthermore, once calibrated to a tree species, the trunk model predicts heartwood and sapwood profiles of conspecific trees in similar growing environments based only on the age and height of a tree (cross-validation/prediction; R 2: 68–98%). The fewer and often contrasting parameters needed for the trunk model make it a potentially useful complementary tool for biologists and foresters. [ABSTRACT FROM AUTHOR]

Relationships between tree size and water use indicate how soil water is partitioned between differently sized individuals, and hence competition for water. These relationships are rarely examined, let alone whether there is consistency in shape across populations. Competition for water among plants is often assumed to be size-symmetric, i.e. exponents (b1) of power functions (water use ∝ biomassb1) equal to 1, with all sizes using the same amount of water proportionally to their size. We tested the hypothesis that b1 actually varies greatly, and based on allometric theory, that b1 is only centered around 1 when size is quantified as basal area or sapwood area (not diameter). We also examined whether b1 varies spatially and temporally in relation to stand structure (height and density) and climate. Tree water use ∝ sizeb1 power functions were fitted for 80 species and 103 sites using the global SAPFLUXNET database. The b1 were centered around 1 when tree size was given as basal area or sapwood area, but not as diameter. The 95% confidence intervals of b1 included the theoretical predictions for the scaling of plant vascular networks. b1 changed through time within a given stand for the species with the longest time series, such that larger trees gained an advantage during warmer and wetter conditions. Spatial comparisons across the entire dataset showed that b1 correlated only weakly (R 2 < 12%) with stand structure or climate, suggesting that inter-specific variability in b1 and hence the symmetry of competition for water may be largely related to inter-specific differences in tree architecture or physiology rather than to climate or stand structure. In conclusion, size-symmetric competition for water (b1 ≈ 1) may only be assumed when size is quantified as basal area or sapwood area, and when describing a general pattern across forest types and species. There is substantial deviation in b1 between individual stands and species. [ABSTRACT FROM AUTHOR]

Pressurized hot water extraction (HWE) treatment has the benefit of simultaneous extraction of hemicellulose-based carbohydrates and modification of the solid phase, but it does not drastically improve wood durability. However, removing hemicelluloses from the wood by HWE treatment creates water-filled spaces in the cell walls which could be filled with modification agent in order to improve the properties of the wood. Without drying, modification agent can be added into the saturated wood via diffusion. The esterification of wood with citric acid (CA) improves resistance to biological deterioration but increases brittleness. However, combining CA esterification with additional chemicals that form links with CA can mitigate brittleness. This study investigated esterification as a method for modifying HWE treated wood. HWE treatment with CA solution (4% w/v) was applied at 120 °C for 3 h to Scots pine (Pinus sylvestris L.) sapwood specimens. The specimens were further modified by diffusion with CA and starch derivatives followed by curing. The applied method changed the moisture properties and chemical composition of the wood. The results showed successful wood bulking. The investigated method slightly improved decay resistance to Coniophora puteana and Trametes versicolor but did not change resistance to Rhodonia placenta. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the dependencies between mechanical properties of modified wood and its color. Within its scope, quantitative changes in color and chemical composition (mass loss, total carbon content, content of extractives and main components of wood), as well as mechanical properties (compressive strength along the grain, strength and modulus of elasticity in longitudinal tension tests, compression across the grain and impact resistance) of the modified Scots pine sapwood, were determined. Modifications were conducted in the atmosphere of superheated steam (time—4 h, temperature of 130, 160, 190, 220 °C). Thermal modification of wood results in an increase in the modulus of elasticity, a reduction of elasticity, longitudinal tensile strength and compressive strength perpendicular to grain. It was found that color parameters ∆E, ∆L and ∆a are linear functions of the modification temperature. The existence of functional dependencies between mass loss, longitudinal tensile strength, radial modulus of elasticity and parameters of ∆E and ∆L makes it possible to determine these properties of modified wood based on color. In turn, chemical analysis indicated that an increase in the temperature of wood modification caused a decrease of holocellulose and hemicelluloses contents, especially in wood samples modified at 220 °C. [ABSTRACT FROM AUTHOR]

Pathogenic diseases frequently occur in drought‐stressed trees. However, their contribution to the process of drought‐induced mortality is poorly understood. We combined drought and stem inoculation treatments to study the physiological processes leading to drought‐induced mortality in Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) saplings infected with Heterobasidion annosum s.s. We analysed the saplings' water status, gas exchange, nonstructural carbohydrates (NSCs) and defence responses, and how they related to mortality. Saplings were followed for two growing seasons, including an artificially induced 3‐month dormancy period. The combined drought and pathogen treatment significantly increased spruce mortality; however, no interaction between these stressors was observed in pine, although individually each stressor caused mortality. Our results suggest that pathogen infection decreased carbon reserves in spruce, reducing the capacity of saplings to cope with drought, resulting in increased mortality rates. Defoliation, relative water content and the starch concentration of needles were predictors of mortality in both species under drought and pathogen infection. Infection and drought stress create conflicting needs for carbon to compartmentalize the pathogen and to avoid turgor loss, respectively. Heterobasidion annosum reduces the functional sapwood area and shifts NSC allocation patterns, reducing the capacity of trees to cope with drought. Summary Statement: Interrelated decreases in carbon and water pools drive drought‐ and pathogen‐induced mortality mechanisms in Picea abies infected by the pathogen Heterobasidion annosum. The pathogen reduces the functional sapwood area and induces a defence response, reducing available carbon to face drought impacts. [ABSTRACT FROM AUTHOR]

High pressure (20 MPa), cyclic, supercritical carbon dioxide (scCO2) treatments can reduce the moisture content of green Pinus radiata sapwood from 150–200% to 35–40%. Such treatments can be used as a dewatering pre-treatment before the kiln-drying of timber. Kiln-drying can utilise various temperature and humidity schedules, targeting around 10% moisture content, with a final stress-relieving steam-conditioning step. After scCO2 treatment and kiln-drying of samples, kiln brown stain was evaluated using the CIE L*a*b* colour space while drying stress was assessed by stress-cup measurements. The most significant results of scCO2 pre-treatment of Pinus radiata sapwood followed by kiln-drying plus steam-conditioning were as follows: Drying from green (36 h from a moisture content (MC) of 164%) using a conventional temperature schedule (90 °C/60 °C) took 2–5 times longer than kiln-drying scCO2 pre-treated boards (37.5% MC) to a target of 10% MC. Colour measurements proved that kiln brown stain does not occur. The use of a steam-conditioning step in reducing internal drying stresses was important irrespective of whether or not there was a scCO2 pre-treatment step. Over all drying schedule combinations, internal drying stress of both green and scCO2 pre-treated timber was similar after kiln-drying plus steam-conditioning. However, using only 90 °C/60 °C schedule data, with steam-conditioning, drying stresses were lower using kiln-drying without the scCO2 pre-treatment. This was surprising since the scCO2 step reduced the moisture content to around 37.5% without significant moisture gradients and so a secondary kiln-drying to 10% moisture content could have been expected to yield lower internal stress levels by preventing large moisture gradients to develop during drying. This result confirms the efficacy of the steam-conditioning step following standard kiln-drying. The colour data demonstrating the prevention of kiln brown stain using kiln-drying schedules offers a path to increasing timber quality for interior applications. [ABSTRACT FROM AUTHOR]

Summary: An essential stage in woody plant ontogeny (heartwood (HW) formation) determines tree resistance to weather conditions, wood quality (moisture, colour, resistance to biodegradation), and regulates the proportion of functionally active sapwood (SW) in the total trunk biomass. In this study, the patterns of HW formation depending on tree age and cambial age within the same tree were studied in the North-West of Russia in Scots pine in a lingonberry pine forest. It is shown that HW either repeats the trunk profile or shows a maximum proportion on average at the height of 1.5 m. Models using the square root transformation and logarithm transformation have been proposed to predict the number of annual rings in HW depending on the cambial age. Multiple regression is proposed to predict the radial width in HW. Validation of the developed models on random trees gave a good result. HW formation begins at the age of 17–18 years and continues at the rate of 0.3 rings per year for 20–30-year-old trees, 0.4–0.5 rings per year for 70–80-year-old trees, and about 0.7 rings per year for 180-year-old trees. The lifespan of xylem parenchyma cells ranged from 10–15 years in 20-year-old trees to 70 years in 180-year-old trees. At the age of the previous felling (70–80 years) the HW area in the trunk biomass is about 20%, and in 180-year-old pine forests, it increases to 50%. These data can be used to assess the role of old-growth forests in carbon sequestration. [ABSTRACT FROM AUTHOR]

the selection of Eucalyptus genotypes appropriate for charcoal production depends on both assessing wood features and correlations among them. However, the large number of variables of wood and charcoal makes interpretation complex; thus, it is necessary using statistical techniques to analyze the cluster of variables that influence each sampling element, simultaneously. In addition, the high cost and long time required to set wood and charcoal properties makes it unfeasible to feature a large number of genotypes within a short period-of-time. Accordingly, the aims of the present study are to develop a pre-selection methodology and to recommend Eucalyptus genotypes for charcoal production, based on using cluster multivariate statistics. In total, 64 Eucalyptus genotypes from a clonal database were used in the study; their wood basic density, volume and dry mass per hectare were determined, as well as their heartwood/sapwood ratio. These parameters were used in the pre-selection procedure, which combined classification based on median, variables' individual rank, and Mulamba and Mock selection index. The determination of properties presented by wood and charcoal belonging to the pre-selected genotypes was carried out, and they were used as input variables for clustering analysis based on the Tocher method and on Unweighted Pair Group Method with Arithmetic Mean (UPGMA). The pre-classification methodology was efficient, because it allowed selecting 16 genotypes showing the desired values for the four features used in the pre-selection process. Overall, the properties of wood and charcoal belonging to the pre-selected genotypes were considered satisfactory to be used in steel production. The clustering methods were effective in solving genotype classification issues. Tocher optimization method application was much more practical, because it led to the optimum number of clusters without the need of researcher's intervention, besides the fact that clusters' compliance was similar to that assessed through the UPGMA method. It was possible concluding that genotype numbers 1954, 1453, 1923 and 4296 are the most recommended ones for charcoal production, according to the herein used analysis techniques, based on the study of mean values recorded the features of wood and charcoal in each cluster. • Charcoal production from planted-forest wood is essential for sustainable steel production. • The large amount of genetic Eucalyptus materials available makes the task of selecting the best ones complex. • The large number of quality variables set to each material also impairs the selection of the best ones. • It is essential using statistical techniques to analyze the set of variables that simultaneously influence each sampling element. • The pre-selection and cluster methods could rank the best genetic materials for charcoal production. [ABSTRACT FROM AUTHOR]

• Accurate estimation of tree stem diameter and its internal components are critical for forest management and timber production. • Multitask Learning (MTL) was developed for estimating heartwood diameter, sapwood width, bark thickness, diameter outside bark, and their volumes. • MTL, as one of additive systems, improves performance by simultaneously learning across multiple related tasks. • MTL could accurately predict the diameter and volume of tree stem and its components as expected. Accurate estimations of a tree stem's heartwood diameter (HD), sapwood width (SW), bark thickness (BT) and diameter outside bark (DOB) are essential for volume and biomass calculations, forest management, and optimal timber production. Understanding these components also provides valuable insights into the ecological health and functioning of forest ecosystems. The additive model system, enhanced by machine learning algorithms, offers new tools for estimation. We constructed parametric taper models and nonparametric multilayer perceptron models to compare the accuracy of HD, SW, BT, and DOB estimates based on 3199 upper stem diameter measurements obtained from 103 sample Pinus koraiensis Siebold & Zucc. trees in Northeast China. In the context of the additive model system for tree stem internal components, we utilized nonlinear seemingly unrelated regression (NSUR) as a parametric method and multitask learning (MTL) as a nonparametric method. In the comparison of additive model systems, MTL (nonparametric) performed better than did NSUR (parametric) by improving the accuracy and generalizability of the stem and internal component estimates. The coefficient of determination (R2) for DOB, HD, SW, and BT increased by 0.31%, 1.39%, 4.21%, and 4.31%, respectively. Based on these results, we conclude that the MTL provides a valid option for improving HD, SW, BT, and DOB and enhancing the volume prediction of stem components. [ABSTRACT FROM AUTHOR]

Background and Aims Despite the critical role of woody tissues in determining net carbon exchange of terrestrial ecosystems, relatively little is known regarding the drivers of sapwood and bark respiration. Methods Using one of the most comprehensive wood respiration datasets to date (82 species from Australian rainforest, savanna and temperate forest), we quantified relationships between tissue respiration rates (R d) measured in vitro (i.e. 'respiration potential') and physical properties of bark and sapwood, and nitrogen concentration (N mass) of leaves, sapwood and bark. Key Results Across all sites, tissue density and thickness explained similar, and in some cases more, variation in bark and sapwood R d than did N mass. Higher density bark and sapwood tissues had lower R d for a given N mass than lower density tissues. R d– N mass slopes were less steep in thicker compared with thinner-barked species and less steep in sapwood than in bark. Including the interactive effects of N mass, density and thickness significantly increased the explanatory power for bark and sapwood respiration in branches. Among these models, N mass contributed more to explanatory power in trunks than in branches, and in sapwood than in bark. Our findings were largely consistent across sites, which varied in their climate, soils and dominant vegetation type, suggesting generality in the observed trait relationships. Compared with a global compilation of leaf, stem and root data, Australian species showed generally lower R d and N mass, and less steep R d– N mass relationships. Conclusions To the best of our knowledge, this is the first study to report control of respiration–nitrogen relationships by physical properties of tissues, and one of few to report respiration–nitrogen relationships in bark and sapwood. Together, our findings indicate a potential path towards improving current estimates of autotrophic respiration by integrating variation across distinct plant tissues. [ABSTRACT FROM AUTHOR]

Leptographium terebrantis is an opportunistic root pathogen that has been implicated as a contributing factor of Pinus taeda decline and mortality over the past several decades in central parts of Alabama and Georgia, USA. We assessed the potential of L. terebrantis to initiate crown thinning in young P. taeda trees and hypothesized that L. terebrantis infestation will impose moisture stress on foliage, induce premature senescence, and cause loss of foliage biomass. The study was undertaken in a naturally regenerated 5–7‐year‐old P. taeda stand at Andalusia, Alabama in a completely randomized design using artificial inoculations of L. terebrantis colonized toothpicks. After four years of infestation, the pathogen caused sapwood occlusions and loss of sapwood function but failed to impose moisture stress on needles to induce premature senescence and loss of biomass. The new sapwood formed around the occluded area was devoid of pathogen infestation. The new growth was approximately twice the size of occluded tissue and compensated for the loss of old sapwood function to sustain tree growth. Results demonstrated that young P. taeda trees can tolerate L. terebrantis infection when stand conditions sustain the formation of new sapwood. [ABSTRACT FROM AUTHOR]

Dalbergia sissoo is a woody plant with economic and medicinal value. As the pharmacological qualities and properties of the wood from this plant primarily depend on its extractives, in this study, the metabolomic analysis of extractives from its stems was carried out using UPLC-MS/MS. A total of 735 metabolites were detected from two groups of samples, heartwood and sapwood, with the largest number of terpenoids in type and the largest number of flavonoids in quantity. The PCA and cluster analysis showed significant differences in the metabolite composition between the two groups. The differential metabolites were mainly organic oxygen compounds, flavonoids, and isoflavones. Among the 105 differential metabolites, 26 metabolites were significantly higher in relative content in sapwood than in heartwood, while the other 79 metabolites were significantly higher in relative content in heartwood than in sapwood. KEGG metabolic pathway enrichment analysis showed that these differential metabolites were mainly enriched in three metabolic pathways: Flavonoid biosynthesis, isoflavonoid biosynthesis, and flavonoid and flavonol biosynthesis. This study provides a reference for metabolomics studies in Dalbergia and other woody plants. [ABSTRACT FROM AUTHOR]

Parenchyma is an important component of the secondary xylem. It has multiple functions and its fraction is known to vary substantially across angiosperm species. However, the physiological significance of this variation is not yet fully understood. Here, we examined how different types of parenchyma (ray parenchyma [RP], axial parenchyma [AP] and AP in direct contact with vessels [APV]) are coordinated with three essential xylem functions: water conduction, storage of non-structural carbohydrate (NSC) and mechanical support. Using branch sapwood of 15 co-occurring drought-adapted woody species from the subtropical Bonin Islands, Japan, we quantified 10 xylem anatomical traits and examined their linkages to hydraulic properties, storage of soluble sugars and starch and sapwood density. The fractions of APV and AP in the xylem transverse sections were positively correlated with the percentage loss of conductivity in the native condition, whereas that of RP was negatively correlated with the maximum conductivity across species. Axial and ray parenchyma fractions were positively associated with concentrations of starch and NSC. The fraction of parenchyma was independent of sapwood density, regardless of parenchyma type. We also identified a negative relationship between hydraulic conductivity and NSC storage and sapwood density, mirroring the negative relationship between the fractions of parenchyma and vessels. These results suggest that parenchyma fraction underlies species variation in xylem hydraulic and carbon use strategies, wherein xylem with a high fraction of AP may adopt an embolism repair strategy through an increased starch storage with low cavitation resistance. [ABSTRACT FROM AUTHOR]

The result of this study is the chemical characterization of sapwood (SW) and heartwood (HW) of Fraxinus angustifolia native to Algeria. Lipophilic and hydrophilic extractives were isolated by means of an accelerated solvent extractor (ASE) using hexane and the acetone/water mixture respectively. The acid hydrolysis and methanolysis methods were used to determine cellulose and hemicelluloses contents. The Tappi Standards T 222 and UM 250 allowed Klason and acid-soluble lignin quantification respectively. Alkaline hydrolysis of wood samples followed by HPLC analysis was performed to determine the acetyl groups. The method detailed in TAPPI T 211 (2002) for determining the ash content was used. It was found that the SW and HW of Fraxinus A. had almost similar amounts of the main components, averaging 40.00 wt% cellulose, 28.00 wt% hemicelluloses within 18.00 wt% of xylan, 22.00 wt% lignin, 3% extractives and 0.83 wt% ash. However, the HW contained more triglycerides (0.08 wt%) than the SW (0.02 wt%). On the other hand, mannitol was the most predominant hydrophilic extractive in SW (1.60 wt%) than in HW (1.02 wt%). These findings are useful for practitioners in the paper, biofuel, cosmetics, food, pharmaceutical and chemical industries for the assessment of Fraxinus A. wood chemical treatment parameters. [ABSTRACT FROM AUTHOR]

Summary: Living trees in forests emit methane (CH4) from their stems. However, the magnitudes, patterns, drivers, origins, and biogeochemical pathways of these emissions remain poorly understood.We measured in situ CH4 fluxes in poplar stems and soils using static chambers and investigated the microbial communities of heartwood and sapwood by sequencing bacterial 16S, archaeal 16S, and fungal ITS rRNA genes.Methane emissions from poplar stems occurred throughout the sampling period. The mean CH4 emission rate was 2.7 mg m−2 stem d−1. Stem CH4 emission rate increased significantly with air temperature, humidity, soil water content, and soil CH4 fluxes, but decreased with increasing sampling height. The CO2 reduction and methylotrophic methanogenesis were the major methanogenic pathways in wood tissues. The dominant methanogen groups detected in stem tissues were Methanobacterium, Methanobrevibacter, Rice Cluster I, Methanosarcina, Methanomassiliicoccus, Methanoculleus, and Methanomethylophilaceae. In addition, three methanotrophic genera were identified in the heartwood and sapwood – Methylocystis, Methylobacterium, and Paracoccus.Overall, stem CH4 emissions can originate directly from the internal tissues or co‐occur from soils and stems. The co‐existence of methanogens and methanotrophs within heartwood and sapwood highlights a need for future research in the microbial mechanisms underlying stem CH4 exchange with the atmosphere. [ABSTRACT FROM AUTHOR]