Liriodendron Tulipifera Research Articles

Assessing tree ring δ15N of four temperate deciduous species as an indicator of N availability using independent long-term records at the Fernow Experimental Forest, WV.

Nitrogen deposition in the northeastern US changed N availability in the latter part of the twentieth century, with potential legacy effects. However, long-term N cycle measurements are scarce. N isotopes in tree rings have been used as an indicator of N availability through time, but there is little verification of whether species differ in the strength of this signal. Using long-term records at the Fernow Experimental Forest in West Virginia, we examined the relationship between soil conditions, including net nitrification rates, and wood δ15N in 2014, and tested the strength of correlation between tree ring δ15N of four species and stream water NO3- loss from 1971 to 2000. Higher soil NO3- was weakly associated with higher wood δ15N across species, and higher soil net nitrification rates were associated with higher δ15N for Quercus rubra only. The δ15N of Liriodendron tulipifera and Q. rubra, but neither Fagus grandifolia nor Prunus serotina, was correlated with stream water NO3-. L. tulipifera tree ring δ15N had a stronger association with stream water NO3- than Q. rubra. Overall, we found only limited evidence of a relationship between soil N cycling and tree ring δ15N, with a strong correlation between the wood δ15N and NO3- leaching loss through time for one of four species. Tree species differ in their ability to preserve legacies of N cycling in tree ring δ15N, and given the weak relationships between contemporary wood δ15N and soil N cycle measurements, caution is warranted when using wood δ15N to infer changes in the N cycle.

Evidence for positive priming of leaf litter decomposition by contact with eutrophic pond sediments

Organic matter processing controls the flow of carbon and nutrients through ecosystems. Heterotrophic metabolism within ponds is supported by both terrestrial leaf litter and autochthonous production. We investigated the potential for the priming of leaf litter decomposition in small ponds using microcosms. We incubated senescent tulip poplar (Liriodendron tulipifera) leaf discs in the dark for 130 days either in contact with eutrophic pond sediments or isolated from sediment contact. Leaves that had been in contact with the sediments were significantly less tough and lost more carbon mass following the incubation than leaves that were not in contact with the sediments, indicating that they were decomposing faster. We calculated a positive priming effect of the sediments of 42% and 77% based on the change in toughness and C mass loss, respectively. We further found that leaf discs that were in contact with the sediments had significantly less fungal biomass, measured as ergosterol mass, and less leaf-derived N in fungal biomass than the leaf discs isolated from the sediments. These results indicate that the presence of the more labile organic matter of the sediments alters the rate of organic matter mineralization and the cycling of nitrogen and carbon.

The effect of feedstock composition on fast pyrolysis and upgrading to transportation fuels: Techno-economic analysis and greenhouse gas life cycle analysis

Process economics and greenhouse gas (GHG) emissions are evaluated for the conversion of eleven (11) biomass feedstocks to produce transportation fuels via fast pyrolysis and then pyrolysis oil upgrading via hydrodeoxygenation. The biomass consists of six (6) pure feeds (pine, tulip poplar, hybrid poplar, switchgrass, corn stover, oriented strand board) and five (5) blends. Feedstock blends combine pine, tulip poplar, hybrid poplar, switchgrass, and oriented strand board in various ratios. The assumptions used in this analysis are based on a unique experimental data set. They are “field to wheel” data generated from a multistep experiment that started from biomass preparation and was followed by biomass feedstock conversion to pyrolysis oil, and then finished by pyrolysis oil upgrading to produce hydrocarbon liquid fuel. Process economic results are reported in US dollars per gasoline gallon equivalent (gge) at the minimum fuel selling price (MFSP). For all eleven feedstocks, the largest cost contribution to MFSP is capital-related costs, which is approximately 30%–40% of the MFSP and includes capital depreciation, income tax, and return on investment. Feedstock cost (approximately 30% of MFSP), hydrotreating catalyst cost (13%–18% of MFSP) and labor cost (12%–15% of MFSP) also contribute significant cost to MFSP. Final fuel product yield is one of the most significant parameters affecting the process economics. The highest product yield is from pine feedstock, while switchgrass feedstock gives the lowest yield. Using blends (woody mixed with herbaceous), with which the product yield is still reasonable, may further improve process economics compared to pure feedstocks because of the lower feedstock price for blends. Blend feedstocks cost less than pure feedstock because of greater diversity in feedstock choices, lower risk, and lower transportation costs. GHG reduction does not necessarily align with favorable economics. Process parameters that most significantly affect the life cycle GHG emissions (from feedstock production to vehicle operation) are (1) natural gas used for hydrogen production and electricity usage in fast pyrolysis and pyrolysis oil upgrading, (2) energy usage in the feedstock harvesting, transport, and preprocessing operations, and (3) nitrogen fertilizer usage for growing biomass.

Exploring new applications of tulip tree (Liriodendron tulipifera L.): leaf essential oil as apoptotic agent for human glioblastoma.

Liriodendron tulipifera L. (Magnoliaceae), also known as "tulip tree," is a hardwood plant native to North America, cultivated all over the world and used on an industrial level, especially for its fine wood and to make honey. It has alsobeen traditionally exploited for its antimalarial properties. However, our knowledge about the bioactivity of its essential oil remains patchy. In this research, we focused on the biological evaluation of the volatile fractions obtained from different parts of the plant which are normally discharged by industry, including leaves, flowers, and fruits. For the purpose, the essential oils were obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). Then, they were evaluated as radical scavenging, antioxidant, antimicrobial, and antiproliferative agents by using DPPH, ABTS, FRAP, disk diffusion, and MTT methods, respectively. The significant toxicity exhibited on human tumor cells, namely A375 malignant melanoma, HCT116 colon carcinoma, MDA-MB 231 breast adenocarcinoma, and T98G glioblastoma multiforme cell lines, prompted us to study the mechanism of action by acridine orange/ethidium bromide double staining and caspase 3 assays. Our findings shed light on the potential applications of tulip tree derivatives as anticancer drugs.

Assessment of Anthropogenic Volatile Organic Compounds in Leaves of Two Urban Tree Species in Santiago de Chile

Anthropogenic volatile organic compounds (AVOCs) represent the third largest contribution in gaseous emissions in the urban and peri-urban region of Santiago, the capital of Chile. Some of these compounds are toxic or mutagenic, cause serious damage to human health, and decrease plant growth and development. There is little international information related to atmospheric AVOCs in leaf content from trees exposed to specific sources of pollution, and to our knowledge, there is no research on this topic in Chile. The purpose of this work was to study the leaf content of AVOCs from the Organic Range of Gasoline (ORG: range 6-10 C) emitted by local traffic during the austral summer and spring seasons in leaves of two exotic tree species (Liriodendron tulipifera and Platanus x acerifolia). Leaf samples collected around 2 meters height above the ground were pulverized with a cryogenic mill and eleven chemical components were quantified (toluene, 1,2,4-trimethylbenzene (1,2,4-TMB), styrene, ethylbenzene, ortho, meta and para-xylenes, naphthalene, 1,3,5-trimethylbenzene (1,3,5-TMB), isopropylbenzene and trichloroethene) using GC-MSD MSD. Benzene was detected but not quantified, because it was always under the quantification limit of the technique. Differences in concentrations were found for type of site exposure, season and tree species. The differences found in leaf content of AVOCs in P. x acerifolia exposed to vehicle traffic suggest that the concentration of these contaminants in leaves may be due to AVOC capturing. Considering the content of AVOCs in leaves and not in the whole individual tree, L. tulipifera presented a higher concentration of total AVOCs than P. x acerifolia for both seasons. The Prop-Equiv and OFP of L. tulipifera were very high in summer, being 13.6 and 14.8 times greater, respectively, than the corresponding values for P. x acerifolia.

Changes in gas permeability and pore structure of wood under heat treating temperature conditions

In this study, changes in gas permeability and pore structure of wood are evaluated after heat treatment with temperatures ranging from 190 to 230 °C for 6 h for both hardwood (yellow poplar: Liriodendron tulipifera) and softwood (Korean red pine: Pinus densiflora). The purpose of this study is to investigate changes in pore size, content of three pore types (through pore, blind pore, and closed pore), as defined by IUPAC, and gas permeability by increasing heat treatment temperatures in hardwood and softwood using capillary flow porometry and gas pycnometry. As the heat treatment temperature increased, only through pore porosity increased, causing an increase in gas permeability.

The long-term case for partial-cutting over clear-cutting in the southern Appalachians USA

Prior to the 1950s, common partial harvesting operations in the southern Appalachians USA involved the removal of logs by ground-skidding and the construction of steep access roads and skid trails along stream channels. Little is known about how these historical practices affected long-term vegetation changes. An experimental watershed in the Coweeta Hydrologic Laboratory was partially harvested in the years 1942–1952 according to these exploitive practices. We compared the partial-cut watershed to a clear-cut watershed and an untreated, reference watershed. Using long-term vegetation surveys, we analyzed patterns in aboveground biomass accumulation, species composition and diversity (Shannon’s index Hʹ and species richness) among watersheds. Contrary to our expectations, the partial-cut watershed recovered to reference levels of aboveground biomass and their species composition was similar over time. The clear-cut watershed had greater abundance of tulip poplar (Liriodendron tulipifera) and black locust (Robinia pseudoacacia) than the other two watersheds. The partial-cut watershed increased in diversity over time, but it remained less diverse than the reference watershed; whereas, the clear-cut watershed had lower diversity than the other two watersheds, and its diversity did not change over time. Distributions of functional groups based on water use and nutrient acquisition traits, and shade tolerance were similar between the partial-cut and the reference watersheds, but differed from the clear-cut watershed. By the 2010s, partial-cut and reference watersheds had similar proportions of diffuse-porous (32% and 33%) and ring-porous (48% and 42%) basal area, while the clear-cut watershed had more diffuse-porous (43%) and less ring-porous (36%) species than the partial-cut or reference watersheds. Tree species associated with arbuscular mycorrhiza were more abundant in the clear-cut watershed than the partial-cut or reference watersheds. Overall, the partial-cut watershed, even with the extreme soil disturbance, did not alter long-term species composition and diversity as dramatically as the clear-cut watershed. These results could help forest managers, conservationists, and hydrologists understand the long-term effects of partial-cutting versus clear-cutting.

Early Tree Growth in Reclaimed Mine Soils in Appalachia USA

Surface mining disturbs hundreds of hectares of land every year in many areas of the world, thereby altering valuable, ecologically-diverse forests. Reforestation of these areas after mining helps to restore ecosystem functions and land value. In Appalachia, native topsoil is normally replaced on the surface during reclamation, but waivers allow for brown and gray sandstone materials to be used as topsoil substitutes. Numerous studies report the growth of trees in these substitute mine soil materials, but few studies have compared the height of trees grown in reclaimed mine soils to the heights of trees grown in native soils. This study determined the growth of red oak (Q. rubra L.), white oak (Quercus alba L.), and tulip poplar (Liriodendron tulipifera L.) in two mine soil types which were compared to projected growth in native soils. Heights of tree seedlings in native soils at 11 years were estimated from site indices (SI) from USDA Soil Survey data. At the mine sites, areas with brown and gray mine soils (one site with a mulch treatment) had 12 tree species planted and growth was measured annually for 11 years. Mine soil pH after 11 years was 5.3 for brown mine soils, 6.6 for gray mine soils, 7.0 for mulched mine soils, and 4.1 to 5.2 for native forest soils. After 11 years, tree heights in gray mine soils were significantly lower (0.5 m) than tree heights in brown mine soils (2.8 to 4 m) for all three species. Trees in mulched mine soils were up to 0.7 m taller than trees in un-mulched brown mine soils. After 11 years, red oak height was 6.3 m in native soils and 3 m in brown and mulched mine soils (52% lower); white oak was 7.3 m tall in native soils compared to 3.6 m in brown mine soils (50% lower); and tulip poplar was 11.5 m tall in native soils and 3.5 to 4 m tall in brown and mulched mine soils (70% lower). In gray mine soils, trees were not growing at all. While the trees in brown mine soils are growing, tree growth has not reached projected levels of tree growth in native soils during the first 11 years after planting. The purpose of forestry reclamation is to restore ecosystem diversity and function. This study showed that one measure of ecosystem function, tree growth, was 50% lower on reclaimed mine soils than native forest soils. Maturing mine soils may develop properties over time that are similar to native soils and, with the increased rooting depth, may provide conditions where increased tree growth rates and height may be attained during the next several decades.

The potential to strengthen temperature reconstructions in ecoregions with limited tree line using a multispecies approach

AbstractTree-ring reconstructions of temperature often target trees at altitudinal or latitudinal tree line where annual growth is broadly expected to be limited by and respond to temperature variability. Based on this principal, regions with sparse tree line would seem to be restricted in their potential to reconstruct past temperatures. In the northeastern United States, there are only two published temperature reconstructions. Previous work in the region reconstructing moisture availability, however, has shown that using a greater diversity of species can improve reconstruction model skill. Here, we use a network of 228 tree-ring records composed of 29 species to test the hypothesis that an increase in species diversity among the pool of predictors improves reconstructions of past temperatures. Chamaecyparis thyoides alone explained 31% of the variability in observed cool-season minimum temperatures, but a multispecies model increased the explained variance to 44%. Liriodendron tulipifera, a species not previously used for temperature reconstructions, explained a similar amount of variance as Chamaecyparis thyoides (12.9% and 20.8%, respectively). Increasing the species diversity of tree proxies has the potential for improving reconstruction of paleotemperatures in regions lacking latitudinal or elevational tree lines provided that long-lived hardwood records can be located.

Microbial inoculation influences arbuscular mycorrhizal fungi community structure and nutrient dynamics in temperate tree restoration

Soil microbial communities have a profound influence on soil chemical processes and subsequently influence tree nutrition and growth. This study examined how the addition of a commercial inoculum or forest‐collected soils influenced nitrogen (N) and phosphorus (P) dynamics, soil microbial community structure, and growth in Liriodendron tulipifera and Prunus serotina tree saplings. Inoculation method was an important determinant of arbuscular mycorrhizal fungi (AMF) community structure in both species and altered soil N dynamics in Prunus and soil P dynamics in Liriodendron. Prunus saplings receiving whole forest soil transfers had a higher rhizosphere soil carbon/nitrogen ratio and ammonia content at the end of the first growing season when compared to unmanipulated control saplings. Inoculation with whole forest soil transfers resulted in increased inorganic phosphorus in Liriodendron rhizosphere soils. The number of AMF terminal restriction fragments was significantly greater in rhizosphere soils of Liriodendron saplings inoculated with whole forest soil transfers and Prunus saplings receiving either inoculum source than control saplings. Forest soil inoculation also increased AMF colonization and suppressed stem elongation in Liriodendron after 16 months; conversely, Prunus AMF colonization was unchanged and stem elongation was significantly greater when saplings were inoculated with whole forest soil transfers. Longer term monitoring of tree response to inoculation will be essential to assess whether early costs of AMF colonization may provide long‐term benefits. This study provides insight into how practitioners can use microbial inoculation to alter AMF community structure and functioning, subsequently influencing tree growth and nutrient cycling during the restoration of degraded lands.

Preparation and characterization of electrospun composite nanofibers from poly(vinyl alcohol) /lignocellulose nanofibrils with different chemical compositions

Lignocellulose nanofibrils (LCNFs) were prepared using Liriodendron tulipifera L. wood flour. Electrospun nanofibers were fabricated by mixing the LCNFs with poly(vinyl alcohol) (PVOH). The lignin and hemicellulose contents of the wood flour were controlled with an alkaline-peroxide treatment at a pH of 11.5 using various hydrogen peroxide concentrations. The morphological characteristics, mean diameter, and filtration time of the LCNFs subjected to wet disk milling (WDM) and high-pressure homogenization were determined. Furthermore, the spinning suspension viscosity was measured with various LCNF concentrations and PVOH/LCNF addition ratios. After the alkaline-peroxide treatment, the lignin and hemicellulose contents decreased with an increasing hydrogen peroxide concentration and reaction time. As the lignin content decreased, the nanofibril diameter decreased and the filtration time increased. The diameter decreased further after the homogenization treatment following WDM. The viscosity of the mixed solution increased with an increasing PVOH and LCNF mixed solution concentration and LCNF addition ratio, and decreasing lignin content. Scanning electron micrographs revealed that the diameter of the electrospun nanofibers increased as the mixed solution concentration and LCNFs addition increased, the lignin content decreased, and with the homogenization treatment.

Dendrochronological dating of Rebel’s Rest (40FR512), Franklin County, Tennessee, USA

The structure named Rebel’s Rest was a two-story, Reconstruction-era house located on the campus of the University of the South in Sewanee, Tennessee, before being severely damaged by fire in July 2014. The house was constructed of squared timbers and round logs, with later additions built using sawn lumber. Dendrochronological analyses of timbers and logs salvaged from the house reveals wood from four genera: oak (Quercus spp.), tulip poplar (Liriodendron tulipifera L.), American chestnut (Castanea dentata [Marshall] Borkh.), and pine (Pinus spp.). We statistically and graphically crossdated a total of 251 samples (24,410 rings) with regional chronologies from the ITRDB, resulting in three dated chronologies comprised of oak (1645–1874), tulip poplar (1725–1865), and American chestnut (1710–1864). The majority of samples with cutting dates (95.6%) ended in years 1865–1866, confirming the historically reported construction date of 1866 for the initial structure. The cutting date analysis also confirms two rooms as later additions, Room M (1867) and Room B (1875). Based on ring count and the number of chronologies produced, this research represents the largest known dataset from a single historic structure in the Southeastern US.

American Civil War plant medicines inhibit growth, biofilm formation, and quorum sensing by multidrug-resistant bacteria

A shortage of conventional medicine during the American Civil War (1861–1865) spurred Confederate physicians to use preparations of native plants as medicines. In 1863, botanist Francis Porcher compiled a book of medicinal plants native to the southern United States, including plants used in Native American traditional medicine. In this study, we consulted Porcher’s book and collected samples from three species that were indicated for the formulation of antiseptics: Liriodendron tulipifera, Aralia spinosa, and Quercus alba. Extracts of these species were tested for the ability to inhibit growth in three species of multidrug-resistant pathogenic bacteria associated with wound infections: Staphylococcus aureus, Klebsiella pneumoniae, and Acinetobacter baumannii. Extracts were also tested for biofilm and quorum sensing inhibition against S. aureus. Q. alba extracts inhibited growth in all three species of bacteria (IC50 64, 32, and 32 µg/mL, respectively), and inhibited biofilm formation (IC50 1 µg/mL) in S. aureus. L. tulipifera extracts inhibited biofilm formation (IC50 32 µg/mL) in S. aureus. A. spinosa extracts inhibited biofilm formation (IC50 2 µg/mL) and quorum sensing (IC50 8 µg/mL) in S. aureus. These results support that this selection of plants exhibited some antiseptic properties in the prevention and management of wound infections during the conflict.

Resprouting by seedlings of four North American deciduous broadleaved tree species following experimental burning.

In eastern North American Quercus forests, the historic fire regime, characterized by periodic, low-intensity surface fire, facilitated the development and maintenance of mid-successional Quercus forests across multiple spatial and temporal scales. One physiological mechanism favoring Quercus over mesophytic and/or shade-tolerant deciduous broadleaved species is prolific and vigorous resprouting following topkill. Generalizations regarding interspecific differences in fire-induced resprouting are confounded by interactions between biotic and abiotic factors. The goal of this study was to quantify resprout dynamics by 2- and 3-year-old seedlings of four prominent deciduous broadleaved species (Acer rubrum, Liriodendron tulipifera, Quercus alba, and Q. rubra) following topkill via experimental burning, where seedling age, competition, fire intensity, and light were controlled. Resprouting was independent of fire intensity and seedling size. The resprout rate of Q. rubra (82%) was greater than that of A. rubrum (53%), L. tulipifera (56%), and Q. alba (52%). A second burn conducted a year later did little to inhibit resprouting by topkilled individuals. After both burns, L. tulipifera sprouts were significantly taller than the other species. Although absolute height of Q. rubra sprouts was greater than A. rubrum after the first burn, absolute height of Q. rubra sprouts was lower than A. rubrum following the second burn. Results suggest that broad, cross-genus generalizations may not accurately reflect interspecific differences in resprout potential, which may have implications related to the ability to regenerate and recruit Quercus under a re-introduced periodic fire regime.

An integrated study on air mitigation potential of urban vegetation: From a multi-trait approach to modeling

The ecosystem services provided by urban forests contribute to ameliorate air quality and human well-being in cities. An integrated approach based on direct measurements of leaf functional multi-traits and on estimation of the plant mitigation potential was used for predicting the species-specific impact on air quality of 29 species, including trees and shrubs, commonly present in the urban context. In addition, volatile organic compound (VOC) emissions and ozone forming potential (OFP) of each species were evaluated. At plant levels, pollution deposition equations and the i-Tree Eco model were applied for estimating particulate (PM10) and ozone (O3) removal potential and for calculating carbon dioxide (CO2) storage and sequestration by the studied species. The results highlight the plant species-specific ability to capture atmospheric pollutants based on their physiological (CO2 assimilation and stomatal conductance) and morphological (stomata, trichomes, waxes and cuticular ornamentation) leaf traits. Trees with abundant trichomes, waxes and wrinkled leaf surfaces are considered more suitable for capturing pollutants. Most of the studied species are suitable for urban planning programs as they result for the majority low VOC emitters and consequently are characterized by low or moderate OFP. Annual O3 and PM10 removal of the investigated trees species ranged from about 58–140 g plant−1 yr−1 and from about 17–139 g plant−1 yr−1, respectively. Total tree CO2 storage ranged from about 164–215 kg plant−1 and gross annual CO2 sequestration from 11 to 20 kg plant−1 year−1. Liriodendron tulipifera, Celtis australis, Acer campestre and Acer platanoides, were efficient species in capturing PM10 and absorbing O3. Prunus cerasifera, Quercus cerris, together with Celtis australis, Acer campestre and Acer platanoides, were efficient for carbon sequestration and storage. As aspected, lower potential of pollutant removal and CO2 storage and sequestration were estimated for shrubs, due to their smaller leaf area and structure.

Effect of Torrefaction Temperature on Lignin Distribution of Larix kaempferiC. and Liriodendron tulipiferaL. Cubes and the Impact of Binder on Durability of Pellets Fabricated with the Torrefied Cubes

Larch (LAR) and yellow poplar (YP) cubes were torrefied at 180, 220 and 260°C for 50 min to investigate the effect of torrefaction temperature on chemical composition, fuel properties and pelletability. When increasing the torrefaction temperature from 180 to 220°C, lignin content of torrefied LAR and YP increased from 28 to 34% and from 21 to 23%, respectively. Xylose contents of LAR and YP decreased to 11% at the torefaction temperature of 260°C. The thermal degradation of xylose by the torrefaction treatment has a significant impact on increasing the ash content, higher heating value and weight loss of the torrefied LAR and YP. When the lignin distribution of untreated and 180°C‐torrefied cubes were measured quantitatively by the microscopic analysis of SEM–EDX, the amount of lignin existing on the radial‐sectional areas of LAR and YP increased from 7.89 to 18.84% and from 6.37 to 17.71%, respectively. Durability of pellets fabricated with torrefied LAR and YP cubes decreased with the increase of torrefaction temperature. By the adjustment of a moisture content for the torrefied particles, durability of torrefied LAR pellets improved by 8–11% but that of YP decreased by 2–21%. Addition of 2 wt% starch, lignin and protein as a binder to 180°C‐ and 220°C‐torrefied LAR and YP affected the increase of pellets durability. Accordingly, it can be concluded that the addition of binder or moisture is needed to produce durable pellets made with torrefied LAR and YP while accounting for costs associated with the binders. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019

H₂ Production from Yellow Poplar Gasification Over Ni/Spent FCC.

Ni/spent FCC catalyst was applied as the catalyst on the catalytic pyrolysis and gasification of yellow poplar (YP). Larger amount of gas (CO, CO₂, H₂, C1~C₄) was produced by applying Ni/spent FCC catalyst to the catalytic pyrolysis and gasification of YP. Ni/spent FCC catalyst also increased the selectivity of phenols and aromatic hydrocarbons in oil product during the pyrolysis and gasification of YP. Overall catalytic performance of Ni/spent FCC catalyst was similar level with that of Ni/γ-Al₂O₃, suggesting its potential use.

Investigation into torrefaction kinetics of biomass and combustion behaviors of raw, torrefied and char samples

Thermal decomposition of sugarcane bagasse (SCB), yellow poplar (YP), and biomass polymers (xylan, cellulose and lignin) were studied under isothermal conditions using a specially designed thermogravimetric analyzer (Quartz Wool Matrix, QWM) in the temperature range 240–300 °C. Reactivity of biomass was predicted using the measured reactivity of three individual polymers and a simple arithmetic superposition principle. The superposition model was modified to increase the prediction accuracies of torrefaction behavior. To evaluate the impact of torrefaction on combustion, the combustion kinetics were also studied for the torrefied SCB and YP, and for the pyrolyzed YP. Activation energies for combustion reaction using the Flynn-Wall-Ozawa (FWO) method for the non-isothermal events were estimated as a function of the degree of conversion. Reactivity indexes were also determined for each sample when 50% of decomposition was reached. Different stages of thermal degradation of each polymer in the material were identified in the combustion process, which was significant only at the low heating rate. The results confirm that the reaction rate decreases with torrefaction, thereby increasing the reaction index. The char from the torrefied biomass has more thermal stability than the char from raw biomass, which can be confirmed by the increased reaction index.

Particle size analysis of airborne wood dust produced from sawing thermally modified wood

Thermal modification imparts desirable properties in wood, including increased dimensional stability and greater resistance to fungal decay. While there is a substantial amount of performance data for thermally modified wood, there is little data available regarding the airborne particle size distribution of dust produced when processing thermally modified wood using standard machining equipment. Therefore, utilizing a Micro-Orifice Uniform Deposit Impactor, this research analyzed the size distribution of airborne particles produced when processing 170 °C thermally modified yellow poplar, red maple, white ash, aspen, and balsam fir on an industrial table saw. Ultimately, the aim of this research was to provide preliminary data that may assist wood products industry manufacturers and environmental health and safety officials in identifying potential hazards of airborne thermally modified wood dust. The study revealed slight differences in airborne particulate matter (PM) by wood species. The unmodified yellow poplar, red maple, and white ash all had relatively similar amounts of PM10 (~ 29%), while balsam fir (~ 10%) had the least amount. The unmodified yellow poplar also had the highest amount of PM2.5 and PM1, 14% and 10%, respectively, while the balsam fir had the least amount of PM2.5 and PM1, 2.00% and 1.45%, respectively. Thermally modified yellow poplar had the highest PM10, PM2.5, and PM1. Statistical analysis revealed that none of the five wood species had a significant difference (p < 0.05) in particle size distribution between unmodified and thermally modified forms.

The complete mitochondrial genome of tulip tree, Liriodendron tulipifera L. (Magnoliaceae): intra-species variations on mitochondrial genome

Liriodendron tulipifera L. is easily recognized by its heart-shaped of leaves and can grow up to 60 meters in North America. In this study, we presented second complete mitochondrial genome of L. tulipifera to understand intra-species variations. Its length is 156,387 bp and contains 66 genes (42 protein-coding genes, three rRNAs, and 21 tRNAs). The overall GC content of the mitochondrial genome is 43.5%, 365 single nucleotide polymorphisms (SNPs; 0.07%), and 2117 insertions and deletions (INDELs; 0.38%) are identified. Most of INDELs are from 1980 bp deletions on this mitochondrial genome. Phylogenetic trees show that intra-species relation in both Liriodendron and Arabidopsis shows are clustered tightly in each clade. In addition, monocots and eudicots are positioned in different manner from classical plant taxonomy, requiring more researches.