Wood Mass Research Articles

Potential Hazard of Open Space Fire in Black Pine Stands (Pinus nigra J.F. Arnold) in Regard to Fire Severity

Black pine (Pinus nigra J.F. Arnold) is one of the most important reforestation species for dry and rocky terrain in the sub-Mediterranean zone. Fire is an important factor in black pine stands that largely defines the distribution range of black pine and the floristic composition of its stands. Fire causes less damage during autumn or early spring when tree cones contain ripe seeds that can partially reforest burnt surfaces. Every fire is a potentially significant threat to forest habitats. There are many damages, from direct damages to wood mass and reforestation costs, to indirect ecological, edaphic, protective damages and the loss of biological diversity. The aim of prevention works in forestry is to reduce the number of fires and reduce burnt surface area per fire. Research was based on vegetation analysis performed on each experimental plot in a black pine stand. The assessment of fire severity was performed using the Canadian Forest Fire Weather Index (FWI). The assessment of the severity of fire indicates the suitability of conditions for the occurrence of forest fires, and enables sound and effective protective methods beginning with silvicultural works. The results indicate better quality stands in the higher parts of the sub-Mediterranean area. Taking into account the climatic parameter, the areas on the border with the continental climate have better habitat conditions for black pine. Also, attention should be focused on 2012 and 2015. High values (Figure 13 – 16.22, Figure 11 – 6.99, Figure 8 – 8.38, Figure 7 – 12.02 and 12.25, Figure 5 – 8.32) indicate the overlapping of extremely dry periods and extremely high summer temperatures, and probably a strong wind influence that further increases the index. Fire severity assessments indicate the suitability of conditions for the onset of fire.

Replacement of Polymer Fibers with Hemp Fibers in Concrete

In our experiment, we tried to replace polymer fibers with hemp fibers and verify whether the properties and advantages of polymer fibers in concrete will be retained even with this interchange. Polymer fibers are added to the mixer to produce fresh concrete or mortar, and we did the same in our case. Polymer fibers do not replace conventional structural reinforcement of concrete, but improve some properties, such as suppressing and controlling cracking in concrete, reducing plastic settling and cracking in concrete settling, improving concrete toughness, etc. Cannabis and its cultivation have a long tradition. The growing season lasts about four months and during that time at least 2.5 times more wood mass grows on one hectare than in the same forest area. The plant consists of root, leaves, seeds and stalk, which contains about a quarter of the fiber and the rest is a woody mass, the so-called shives. We used only hemp fiber in concrete. Hemp fiber excels in its strength, durability and natural protection against pests. Sets of beams according to EN 196-6 were produced for the proposed solution. Although the article deals with hempcrete, i.e. concrete, the tests were performed according to the cement testing standard. In total, three blends were produced with different hemp fiber ratios, three strips each. Compressive strength and flexural tensile strength were measured.

Effects of wood resource size and decomposition on hyphal outgrowth of a cord-forming basidiomycete, Phanerochaete velutina

To assess the relationship between resource use and hyphal growth in a cord-forming basidiomycete, Phanerochaete velutina, soil microcosm experiments were conducted using wood blocks of three different sizes in three different soil quantities, thereby simulating the different amounts of available nutrients. The highest percentage weight loss was observed in the smallest wood blocks after a 27-d incubation period in soil microcosms, although the percentage weight loss over the 2-month pure culture colonization prior to inoculation was not significantly different among various block sizes. The greatest hyphal outgrowth was also observed in the smallest wood blocks and was positively associated with wood decay. The slopes of the regression lines between hyphal coverage and percentage wood mass loss were identical among different wood sizes, but the slopes between hyphal coverage and absolute wood mass loss were steeper in the smaller wood blocks than that in largest one. These results suggest that the level of intensity of mycelial foraging for new resources in the soil depends on the percentage of the amount of wood resource utilized, and not on the absolute amount of carbon obtained from the wood.

Wood delignification with aqueous solutions of deep eutectic solvents

The development of a sustainable wood fractionation has been a goal for the pulp and paper industries to develop a bioeconomy. The use of green solvents, in particular deep eutectic solvents (DES) has been explored to accomplish such goal. This work unveils the potential of DES aqueous solutions (at 50 wt% water content) as green solvents for the Eucalyptus globulus Labill. wood delignification. Aqueous solutions of propionic acid:urea - PA:U (2:1), urea:choline chloride - U:Ch[Cl] (2:1), lactic acid:choline chloride - LA:Ch[Cl] (10:1) and p-toluenesulfonic acid:choline chloride - PTSA:Ch[Cl] (1:1) were investigated. The delignification process was assisted by the addition of mineral (H2SO4 and HCl) or organic (PTSA) acids to efficiently promote wood matrix disruption and further lignin extraction. This process enabled solid pulp and lignin as separated fractions, which were characterized by analytical, optical and spectrometric methods. The influence of each DES on the morphology of cellulose fibers in solid pulp and the chemical structure of isolated lignin fractions was evaluated. The best system allowing delignification while preserving the cellulose fibers (comparable to Kraft cellulose pulp) and lignin structure was PA:U (2:1) aqueous solution with 25 wt% PTSA. A mild wood delignification process (363.15 K for 8 h) using this DES allowed to obtain a cellulose pulp yielding 59.50 ± 0.51 wt% of the initial wood mass and containing only 3.86 ± 0.10 wt% residual Klason lignin content. This innovative approach led to 80.64 wt% lignin extraction from E. globulus wood at mild conditions showing its potential for industrial application. Furthermore, 40.73 wt% of the initial lignin was recovered from DES liquor by a simple precipitation with water.

Comparison of the Accuracy of Methods for Calculating the Volume of Standing European Beech Trees

The paper presents results of the analysis of the accuracy of calculating the volume of standing trees, calculated according to the method used in forestry practice, based on the principle of full calipering of all marked trees with the following calculation of mean height and standing volume according to the method of uniform volume curves. This volume was compared with the exact method for calculating the volume of actual removals including small wood in the beech stands of Little Carpathians in the territory of Lesy Slovenskej republiky, š.p. (Forests of the Slovak Republic, State Enterprise), branch establishment in Smolenice. The values of marked felling (standing trees) and the values of removals including logging residues left on the site will be compared and the difference expressed in percent. The difference between the values in percent is fitted with the accuracy of calculated standing volume (marked logging) established by the author of the method for calculating uniform volume curves, i.e. Halaj. A model curve is chosen by means of the directly detected value of mean stand quantity (mean height, mean diameter, age, site class etc.). The system of uniform volume curves links up with these quantities and gives volumes of individual trees for all diameter classes and corresponding heights. The method of uniform volume curves is used in Slovakia to calculate the volume of marked logging. Results of the analysis show that the volume of standing trees calculated according to the method of uniform volume curves is in reality underestimated by about 5% as compared with the actual volume of processed wood mass including logging residues left on the site. Thus, the calculation inaccuracy in forestry practice is exceeded by the above mentioned 5% as compared with the permitted deviation established through the method of uniform volume curves. Solution of this problem is a proposal submitted to the National Forest Centre in Zvolen for the elaboration of volume tables for the new ecotype of European beech.

Differential Expression of a Putative Copper Homeostasis CutC Gene in Fibroporia radiculosa During Initial Decay of Copper-Treated Wood

Abstract Living organisms require copper for several cellular processes. Yet intracellular concentrations of copper must be regulated to avoid toxicity. Not much is known about mechanisms of copper regulation in wood decay fungi. However, one putative annotation for a copper homeostasis CutC gene (FIBRA_00129), found in other brown-rot wood decay fungi, has been annotated in Fibroporia radiculosa. The aim of this study was to evaluate wood mass loss and differential expression of FIBRA_00129 during initial decay of untreated and copper-treated wood by two copper-tolerant F. radiculosa isolates (FP-90848-T and L-9414-SP) compared with copper-sensitive Gloeophyllum trabeum. Untreated southern pine (Pinus spp.) and ammoniacal copper citrate treated southern pine at three concentrations (0.6%, 1.2%, and 2.4%) were used in a 4-week-long standard decay test. Results showed G. trabeum was unable to decay copper-treated wood while both F. radiculosa isolates successfully decayed southern pine at all copper concentrations. G. trabeum and F. radiculosa L-9414-SP showed no detectable FIBRA_00129 expression over the course of this study. F. radiculosa FP-90848-T showed greater FIBRA_00129 downregulation on copper-treated wood than on untreated wood (P = 0.003). Additionally, there was greater FIBRA_00129 downregulation in F. radiculosa FP-90848-T at week 3 compared with other weeks (P = 0.015). Future studies are needed to further evaluate FIBRA_00129 during the decay process to determine its potential role in copper-tolerance.

Decomposition of Organic Chemical Components in Wood by Tropical Xylaria Species.

The ability of Xylaria species obtained from tropical wood and leaf litter to cause a mass loss of lignin and carbohydrates in wood was examined in vitro with pure culture decomposition tests. The mass loss of wood of four tree species caused by nine Xylaria isolates ranged from 4.5% to 28.4% of the original wood mass. These Xylaria isolates have a potential ability to decompose lignin and other recalcitrant compounds, collectively registered as acid unhydrolyzable residues or Klason lignin in wood. The origin of isolates (i.e., isolates from wood versus leaf litter) did not affect the mass loss of acid unhydrolyzable residue in wood. The Xylaria isolates tested generally caused a selective decomposition of polymer carbohydrates in wood in preference to acid unhydrolyzable residue. The mass loss of acid unhydrolyzable residue caused by Xylaria isolates varied with the tree species of the wood and was negatively related to the initial content of acid unhydrolyzable residue in wood, implying the limiting effect of lignin and recalcitrant compounds on wood decomposition by Xylaria isolates.

The Impacts of the Energy Potential of Forest Biomass on the Local Market: An Example of South-Eastern Poland

Forest biomass is and will remain a primary source of renewable energy in many EU countries in the coming years. The aim of this study was to determine the energy potential of forest biomass on a regional scale with regard to the needs of its inhabitants in terms of electricity and heat consumption. The study was carried out in south-eastern Poland. Energy potential was calculated based on the determined wood mass and calorific value of wood. The current level of forest biomass acquisition satisfies 4.2% of the needs of the local market in terms of electricity and heat consumption. Taking into account high forest cover of the region (40%), the 60% annual increment of total harvesting, and obtaining biomass at the level of 30% of the total harvesting, waste wood from the forest can meet 58.1% of the needs of the local market in terms of electricity consumption and 14.4% of the need for thermal energy consumption. There is a certain niche in the fuel wood market that is currently unused, presenting the opportunity to develop this sector and generate additional jobs in local markets. However, the increase in obtained forest biomass must be in accordance with the principles of sustainable development.

Optimization of Logistics Processes During the Production of Wood Chips

Biomass is one of the sustainable sources for the production of heat and electricity. This paper is devoted to the processing of wood waste. It is an analysis of wood chips processing from the process of balancing the brushwood after toll harvesting, including the transport of processed wood mass to the heating company. MS Project software was used to optimize this production process.

Contribution of fungal and invertebrate communities to wood decay in tropical terrestrial and aquatic habitats.

Wood is a major carbon input into aquatic ecosystems and is thought to decay slowly, yet surprisingly little terrestrial carbon accumulates in marine sediments. A better mechanistic understanding of how habitat conditions and decomposer communities influence wood decay processes along the river-estuary-ocean continuum can address this seeming paradox. We measured mass loss, wood element, and polymer concentrations, quantified invertebrate-induced decay, and sequenced fungal communities associated with replicate sections of Guazuma branch wood submerged in freshwater, estuarine, and near-shore marine habitats and placed on the soil surface in nearby terrestrial habitats in three watersheds in the tropical eastern Pacific. Over 15months, we found that wood decayed at similar rates in estuarine, marine, and terrestrial sites, reflecting the combined activity of invertebrate and microbial decomposers. In contrast, in the absence of shipworms (Teredinidae), which accounted for ~40% of wood mass loss in the estuarine habitats, decay proceeded more slowly in freshwater. Over the experiment, wood element chemistry diverged among freshwater, estuarine, and marine habitats, due to differences in both nutrient losses (e.g., potassium and phosphorus) and gains (e.g., calcium and aluminum) through decay. Similarly, we observed changes in wood polymer content, with the highest losses of cellulose, hemicellulose, and lignin moieties in the marine habitat. Aquatic fungal communities were strongly dominated by ascomycetes (88-99% of taxa), compared to terrestrial communities (55% ascomycetes). Large differences in fungal diversity were also observed across habitats with threefold higher richness in terrestrial than freshwater habitats and twofold higher diversity in freshwater than estuarine/marine habitats. Divergent decay trajectories across habitats were associated with widespread order-level differences in fungal composition, with distinct communities found in freshwater, estuarine and marine habitats. However, few individual taxa that were significantly associated with mass loss were broadly distributed, suggesting a high level of functional redundancy. The rapid processing of wood entering tropical rivers by microbes and invertebrates, comparable to that on land, indicates that estuaries and coastal oceans are hotspots not just for the processing of particulate and dissolved organic carbon, but also for woody debris and for the breakdown of lignin, the most recalcitrant polymer in plant tissue.

Research of Mechanism of Fire Protection with Wood Lacquer

The effect of the composition on the weight loss of wood protected by a coating based on inorganic and organic substances in the process of thermal exposure, which is a feature of the study of the flame retardant effectiveness of the composition, is investigated. The solution of this problem is carried out by specially developed methods. The influence of fire protection under the influence of high-temperature heat flux on the change in the process of loss of mass of fire-protected wood is determined and the mechanism of kinetics of action of the composition is characterized, which is characterized by a decrease in the speed of flame propagation and mass loss. The results of thermogravimetric studies determined the weight loss of the coatings as a function of temperature, the results of which investigated the activation energy at the temperature decomposition of the coatings and found that for wood it was 36.56 kJ / mol, and in the case of fire protection it increased 2.3 times. which makes it possible to conclude that it is advisable to use lacquer varnish to improve the fire retardant efficiency of wood. Thus, for the specimen of fire-retardant lacquer wood, there is a gradual decrease in temperature, ie, the work of the coating is fixed, and, accordingly, the activation energy is increased during the decomposition of the wood. In order to establish the flame retardant efficiency in the application of high-temperature blowing lacquer, studies were conducted to determine the combustibility index of wood by mass loss, flame spread and temperature increase of flue gases and found that when processing wood goes to the group of combustible materials with a burning index.

Pressurized hot water extraction of Scots pine sapwood: effect of wood size on obtained treatment products

The efficiency of hot water extraction (HWE) is dependent on the size of treated wood. While previous research regarding this size-effect has focused on HWE treating sawdust and wood chips, this study investigated its effect on wood blocks with precise dimensions and a broad range of treatment conditions. Scots pine (Pinus sylvestris L.) sapwood samples with dimensions of 10 × 10 × 20 mm3 and 25 × 25 × 50 mm3 (R × T × L) were HWE treated at 130–170 °C for 40–200 min using liquid-to-solid ratios of 4–20. Our results showed that wood mass loss, which was primarily caused by the decomposition of hemicelluloses, was larger when using small samples. This was mainly assigned to a higher quantity of acetone-soluble decomposition products that remained within the large samples, due to longer distances for diffusion and mass transfer from the wood blocks to the extraction liquid. In line with wood mass loss differences, the amount of dissolved compounds (i.e., carbohydrates) in the extraction liquid at different treatment severities was dependent on the wood size, while the liquid-to-solid ratio had only modest effects. However, composition changes of the extraction liquid, in particular changes in the proportion of poly- and monocarbohydrates with increasing treatment severity, were similar for both sample sizes.

Using Wood Rot Phenotypes to Illuminate the "Gray" Among Decomposer Fungi.

Wood-decomposing fungi use distinct strategies to deconstruct wood that can significantly vary carbon release rates and fates. White and brown rot-type fungi attack lignin as a prerequisite to access carbohydrates (white rot) or selectively remove carbohydrates (brown rot). Soft rot fungi use less well-studied mechanisms to deconstruct wood (e.g., cavitation and erosion). These fungi often co-exist in nature, creating a balance in carbon turnover that could presumably “tip” in a changing climate. There is no simple genetic marker, however, to distinguish fungi by rot types, and traditional black and white distinctions (brown and white, in this case) cannot explain a spectrum of “gray” carbon loss possibilities. In this study, we tested 39 wood-degrading fungal strains along this spectrum of rot types. We tracked wood mass loss and chemical changes in aspen blocks in early- to mid-decay stages, including three signatures of fungal nutritional mode measured from wood rather than from fungus: dilute alkali solubility, water-soluble monosaccharides, and lignin loss (%) relative to density loss (%) (L/D). Results were then plotted relative to rot types and correlated with gene counts, combining new data with past results in some cases. Results yielded a novel distinction in soluble monosaccharide patterns for brown rot fungi, and reliable distinctions between white and brown rot fungi, although soft rot fungi were not as clearly distinguished as suggested in past studies. Gene contents (carbohydrate-active enzymes and peroxidases) also clearly distinguished brown and white rot fungi, but did not offer reliable correlation with lignin vs. carbohydrate selectivity. These results support the use of wood residue chemistry to link fungal genes (with known or unknown function) with emergent patterns of decomposition. Wood signatures, particularly L/D, not only confirm the rot type of dominant fungi, but they offer a more nuanced, continuous variable to which we can correlate genomic, transcriptomic, and secretomic evidence rather than limit it to functional categories as distinct “bins.”

Effects of aqueous ammonia vapor on the color and chemical structure of Robinia pseudoacacia and oak woods

Aqueous ammonia vapors were found to affect the color and structure of oak (Quercus L.) and Robinia pseudoacacia L. woods. The modification process was performed using 5% or 10% ammonia concentration at a temperature of 120 °C, 130 °C, or 140 °C. Wood mass and volume change coefficients were determined. The degree of wood discoloration was determined using the Commission Internationale de l’Eclairage (CIE) Lab system, and the changes to the chemical structure were determined using the Fourier transform infrared (FTIR) technique. The samples darkened due to the modification. They also became less red and less yellow. It was found that Robinia wood was more discolored. The total color change (ΔE*) of Robinia wood ranged from 39.0 to 41.9, and of oak wood ranged from 26.8 to 33.3. The L* and b* color coordinates had a significant effect on the ΔE. Analysis of variance showed that in most cases both the concentration of the aqueous ammonia solution and the process temperature alone did not cause significant differences in the colour of the wood (GenStat 18ed (VSN International 2015)). However, the interaction between concentration and temperature was important. Analysis of wood structure via FTIR showed that during the applied treatment, wood underwent chemical changes and that the effects were different in the compared species.

Changes in Carbon Sequestration in Wood During Decay by Brown- and White-Rot Fungi

Wood decay is a releasing process of carbon fixed in the wood. The study on carbon sequestration change caused by decay can provide a theoretical basis for wood preservation and utilization. At present, there are few reports on decay influence on wood carbon emission and no corresponding quantitative data. Therefore, one broad-leaved species, Poplar, and one coniferous species, Korean pine, were selected as the research object, and brown rot fungus (Gloeephyllum trabeum) and white rot fungus (Coriolus versicolor) were used to conduct accelerated decay test on wood samples in the laboratory. During decay, specimens were taken out in different periods to measure chemical properties, mass loss and carbon sequestration. The influence of decay time on carbon sequestration, chemical component and mass loss were then analyzed and the change rule of carbon sequestration were finally studied. The results showed that with increasing decay time, the relative carbon sequestration content of wood affected by different types rot fungi decreased, which was consistent with the change rule of mass loss, indicating that decay would lead to a loss of wood mass and affect its carbon sequestration. However, the absolute carbon sequestration (measured value of carbon sequestration) after brown rot treatment did not decrease but increased slightly, which was different from previous expectation. According to the analysis, with increasing brown rot time, the absolute content and proportion of lignin in wood samples increased slightly, while the corresponding value of holocellulose (including α-cellulose and hemicellulose) decreased significantly. The carbon content of lignin per unit mass is higher than that of holocellulose (Poplar 64.08% > 37.38%; Korean pine 66.37% > 35.94%), resulting in absolute carbon sequestration in wood increases instead of decreases. In conclusion, the change of lignin proportion during the process of brown rot is the decisive factor affecting the change of absolute carbon sequestration. This study focused on two aspects of wood decay and wood carbon sequestration, systematically analyzed the change rule and internal mechanism of wood carbon sequestration with the increase of wood decay degree, and accumulated basic data for wood carbon emission reduction and wood prevention.

Properties of modified wood according to treatment technology and thermo-vacuum process for birch (Betula pendula Roth) veneers

Thermally modified birch (Betula pendula Roth) veneers that had been subjected to wood treatment technology (WTT) or thermo vacuum (TV) processes were compared in this study. After modification of veneers in the range of temperatures from 160 °C to 218 °C and times from 0.5 h to 3 h, the color, mass loss, density, tensile strength, hygroscopicity, and decay resistance against brown rot fungus Coniophora puteana were determined. Treatment regimes with the greatest mass loss were at 217 °C for 3.0 h in TV (7.8%) and 160 °C for 0.8 h in the WTT (6.7%). As expected, wood mass loss correlated well with moisture exclusion efficiency (MEE) in all relative humidity (RH) environments (r = 0.95 to 0.99). Strength loss in the WTT was considerable compared to the TV process (57% and 40%, respectively). The resistance against brown rot fungus was moderate with a mass loss of 12% to 33%. Among the investigated samples, the regime 217/3.0/TV showed the best resistance against brown rot fungus and acceptable other properties.

Methodology matters for comparing coarse wood and bark decay rates across tree species

Abstract The importance of wood decay for global carbon and nutrient cycles is widely recognized. However, relatively little is known about bark decay dynamics, even though bark represents up to 25% of stem dry mass. Moreover, bark presence versus absence can significantly alter wood decay rates. Therefore, it really matters for the fate of carbon whether variation in bark and wood decay rates is coordinated across tree species. Answering this question requires advances in methodology to measure both bark and wood mass loss accurately. Decay rates of large logs in the field are often quantified as loss in tissue density, in which case volume depletions of bark and wood can yield large underestimations. To quantify the real decay rates, we assessed bark mass loss per stem surface area and wood mass loss based on volume‐corrected density loss. We further defined the range of actual bark mass loss by considering bark cover loss. Then, we tested the correlation between bark and wood mass loss across 20 temperate tree species during 4 years of decomposition. The area‐based method generally showed more than 3‐fold higher bark mass loss than the density‐based method (even higher if considering bark cover loss), and volume‐corrected wood mass losses were 1.08–1.12 times higher than density‐based mass loss. The deviation of bark mass loss between the two methods was higher for tree species with thicker inner bark. Bark generally decomposed twice as fast as wood across species, and faster decaying bark came with faster decaying wood (R2 = 0.26, p = 0.006). We strongly suggest using corrected volume when assessing wood mass loss especially for the species with faster decomposable sapwood and all the wood at advanced decay stages. Further studies of coarse stem decomposition should consider trait ‘afterlife’ effects of inner bark and estimate fraction of stem bark cover to obtain more accurate decay rates. Our new method should benefit our understanding of the in situ dynamics of woody debris decay and monitoring research in different forest ecosystems world‐wide, and should aid meta‐analyses across diverse studies.

Habitat‐specific effects of bark on wood decomposition: Influences of fragmentation, nitrogen concentration and microbial community composition

Abstract Identifying the drivers of decomposition is critical for understanding carbon cycling dynamics in forest ecosystems. Woody biomass is an important pool of carbon, composed of bark and underlying wood which vary in structure, nutrient concentrations and exposure to the environment. We hypothesized that higher nutrient concentrations in bark would speed the decomposition of underlying wood, and that this effect would be greater in streams, where nutrients are less available to decomposers than on land. Replicate branches of three tree species, with and without bark, were placed in streams and on land in a lowland tropical forest in Panama. After 3 and 11 months of decomposition, we measured mass loss and nitrogen (N) concentrations and sequenced the fungal and bacterial communities of both wood and bark tissues. While bark decomposed faster than the underlying wood and had higher N concentrations, bark presence slowed wood mass loss. Nitrogen concentration could account for interspecific variation in wood mass loss, but not bark mass loss. In contrast, bark mass loss, but not wood mass loss, was faster in streams than on land, suggesting fragmentation is more important for bark mass loss in streams. Differences in fungal and bacterial community composition between bark and wood substrates were significant but small. Our results indicate that bark can slow wood decomposition instead of promoting it, and that at least for branch wood, the primary drivers of decomposition differ between bark and wood. Differences in the factors driving decomposition rate between bark and wood suggest that the contribution of bark to the decomposition of woody biomass may depend on habitat. A free Plain Language Summary can be found within the Supporting Information of this article.

Porosity and volume assessments of large wood (LW) accumulations

The formation of large wood (LW) accumulations during floods represents a major hazard for constricted river cross-sections, e.g. bridges and weirs, as it affects flow hydraulics and sediment transport. To better assess LW accumulations, reliable strategies and techniques are required. There are currently practical limits on monitoring accumulation configurations. Both laser scans and photogrammetric techniques can be used to scan the outer contours of LW accumulations, but cannot practically assess the wood content and porosity. Details of the outer deposit are captured in high resolution, but the core of the deposit remains occluded, and estimation is necessary. This becomes more challenging for deposits of increasing size (relative to wood elements). To develop a more efficient workflow for LW accumulation assessment in the field, we performed a laboratory study to develop a relationship between the envelope volume of water-worked LW jams during a single flood hydrograph and the volume of woody elements within (explicitly accounting for porosity). We used photogrammetric techniques, now in common use for reconnaissance surveys of debris accumulations, on wood accumulations scaled for the laboratory. The study's aim is to develop a semi-automated assessment method, enabling efficient image acquisition, processing and computation of LW accumulation volume. Using a multi-camera array above the laboratory channel, and applying Structure from Motion photogrammetry, we developed 3D models for 16 experimental flow-formed wood accumulations, each with >50 individual wooden dowels. No correlations were found between porosity and flow magnitude; porosity was found to be similar for most deposits (~66%). As a result of this accumulation structure, the envelope volume used in 3D and 2.5D photogrammetric methods tended to overestimate wood content by 3× and 2.6×, respectively. The results obtained here will contribute to a more reliable volumetric assessment for inventories of wood mass in river systems.

Biorefinery turns wood into renewable chemicals

As the chemical industry seeks more sustainable processes, many researchers believe that using plants as an alternative source of chemicals could help curb carbon dioxide emissions and reduce the world’s dependence on oil and gas. To become economically viable, the biorefineries producing these renewable chemicals will need to squeeze as much value as possible from plants. But plant matter can be frustratingly intractable, with components, like lignin, that are difficult to convert into useful molecules. Researchers in Belgium have now developed an integrated series of chemical processes that can break down lignin and turn 78% of the mass of birch wood into chemical products including phenol, propylene, and ethanol (Science 2020, DOI: 10.1126/science.aau1567). The team, led by Bert F. Sels at KU Leuven, has demonstrated the method at lab scale, and its calculations suggest that a full-scale biorefinery would have a much lower carbon footprint than fossil-based production systems while