Charcoal Formation Research Articles

Projek Perancangan Reaktor Asap Cair Dalam Skala Labolatorium Di Laboratorium Energi Terbarukan : Analisa Konsistensi Produk

This research focuses on the liquid smoke reactor, also known as a pyrolysis reactor. It is a device used in the production of liquid smoke from biomass materials. The pyrolysis process occurs when biomass is heated in the absence of oxygen or with very limited oxygen. As a result, chemical breakdown of polymers into simpler monomers or components takes place. The reactor is designed using stainless steel material with a diameter of 30 cm and a height of 40 cm. The bottom of the reactor is conical in shape. Additionally, the reactor is connected to a condenser via pipes to condense the vapor produced during the pyrolysis process into liquid smoke. Other components in this pyrolysis apparatus include a gas collector and a combustion chamber, which work together to produce liquid smoke from biomass. Under operational conditions, the maximum temperature achieved is 200°C. The operating time to produce charcoal ranges from 4 to 5 hours, depending on the raw material used, such as tea waste, cassava peel, or a mixture of tea waste and cassava peel. The maximum charcoal formation achieved is approximately 80%. By extending the operating time to 8-9 hours using raw materials like coconut shells, coffee grounds, or a combination of coconut shells and coffee grounds, there is an additional 10% increase in charcoal formation. Thus, the overall charcoal formation ratio reaches 90%.

The Combustion and Mechanical Properties of Guanidine Phosphate-Boron Compound-Silica Sol Composite Flame Retardant on Wooden Structure Building Components

ABSTRACT In order to develop a kind of wood with excellent flame retardancy properties, guanidine phosphate, boron compounds and silica sol were used as the main materials to formulate flame retardant solutions with different mass fractions, and to study the fire performance of wood structural building components after impregnation treatment with different flame retardant. The results showed that the LOI values of GPBS-4 and GPBS-5 increased by 82.22% and 97.78%, respectively, compared with that of the natural wood, and the residual charcoal rate of the wood was enhanced by 14.26% and 10.29% at 700°C, indicating that the composite flame retardants have high thermal stability. The results of cone calorimeter test showed that GPBS-4 had the most significant reduction of pHRR1, pHRR2 and THR, which were reduced by 43.01%, 41.06% and 36.97%, respectively, compared with the natural wood. The macroscopic morphology of the charcoal layer showed that the integrity of the charcoal layer of GPBS-4 was better, and the R-value of residual charcoal of GPBS-4 was reduced by 47.92% compared with that of the natural wood obtained by Raman spectroscopy, which indicated that the composite flame retardant effectively promoted the conversion of amorphous carbon into graphite structure, and facilitated charcoal formation in wood. In addition, the addition of silica sol in the flame retardant improved the effect on the mechanical properties of wood.

Thermo-Catalytic Reforming (TCR)–An important link between waste management and renewable fuels as part of the energy transition

The significant progress in energy demands and limited fossil fuel sources, together with environmental concerns, have enforced the study of green, renewable, and sustainable energy sources. Biomass and its residues can be converted into valued fuels and chemicals through advanced thermal conversion technologies. Pyrolysis has been used for a long time for charcoal formation, while intermediate and fast pyrolysis technologies have become of considerable interest in recent years. This substantial interest is because these processes provide different bio-products (synthesis gas, bio-oil and biochar), which can be used directly in numerous applications or as a sustainable energy carrier. This paper investigates an overview of the fundamentals of Thermo-Catalytic Reforming (TCR) technology which is a novel intermediate pyrolysis process combined with a post catalytic reforming unit. This study also identifies the TCR process's features and advantages compared to other pyrolysis technologies, followed by a technical scale unit and the transfer of intermediates in final products. Finally, the treatment of effluents, heat management and implementation of such technologies are discussed. This paper shows how a continuous pyrolysis/reforming plant has been developed and established based on targeted reactor design and in conjunction with preventing major effluent streams, which could have a major impact on the technology's commercial success. Along with two major European projects (To-Syn-Fuel and GreenFlexJET), the TCR technology shall help to overcome the dependency on fossil crude oil and fuels.

PIROLISIS BIOMASSA: REVIEW

The exploitation of fossil energy causes non-renewable reserves to dwindle and causes global warming; climate change endangers living things. Energy sources from the second generation, namely lignocellulosic-based biomass, provide development opportunities, not interfere with food reserves, and are easy to cultivate. One technology that is feasible to use to treat lignocellulosic biomass is pyrolysis. Pyrolysis can convert lignocellulosic biomass (including cellulose, hemicellulose, and lignin) into solid, liquid, and gaseous. The pyrolysis mechanism by thermal decomposition goes through several stages, namely charcoal formation, depolymerization, fragmentation, and other secondary reactions. This paper provides insight into the pyrolysis of lignocellulose and its by-products. Several parameters, such as reaction environment, temperature, residence time, and heating rate, significantly affect the pyrolysis process.

Using analytical pyrolysis and scanning electron microscopy to evaluate charcoal formation of four wood taxa from the caatinga of north-east Brazil

People in north-east Brazil mostly rely on fuelwood and charcoal for domestic energy consumption. Traditionally, four local wood taxa (Mimosa tenuiflora, Mimosa ophthalmocentra, Croton sonderianus and Cenostigma pyramidale) from the caatinga have been selected for this purpose. As the final quality of charcoal is directly related to the charring conditions, as well as the chemical composition of the raw materials and the behaviour of the lignocellulosic matrix during the charring process, the aim of this study was to investigate how far differences in these parameters exert a major control on the charcoal formation, in order to give a molecular insight as to why these particular wood species might be preferred for high-quality charcoal in the perspective of sustainable management and harvesting regimes.Pyrolysis gas chromatography mass spectrometry (Py-GC-MS) and scanning electron microscopy (SEM) were used to study the chemical composition and anatomical changes of the wood samples before and after charring experiments were carried out at 400 and 600 °C. The charring conditions were also reproduced in the controlled environment of the pyrolysis chamber and evolved gas analysis mass spectrometry (EGA-MS) was used for the first time to monitor the evolution of the thermal degradation products.The thermal behaviour of the wood components was different compared to other wood taxa for which comparable data are available. These differences were partially related to the particular nature of the carbohydrate-lignin interactions, to a relatively low level of lignin condensation, and to the substantial presence of gums or resins, which formed charred deposits. These characteristics, often neglected in charcoal analysis, imply that the wood components (especially cellulose) are released more slowly during the charring process, and this translates into the ability of these wood species to retain the main features of their anatomical structure even when exposed to high temperature for a relatively long time. The anatomical alterations observed, such as the loss of the middle lamella, the disappearance of the pit membranes, and the homogenisation of cell walls are ultimately in agreement with the formation of a particularly recalcitrant carbonaceous matrix upon charring at relatively low temperature (400 °C for 2 hours).This study presents the first molecular characterisation of these wood species and some methodological advancement on the use of EGA analysis using isothermal conditions is provided. The role of carbohydrate-lignin interactions and non-lignocellulosic wood components in charcoal production is discussed and the importance of combining chemical data and anatomical observations in wood research is underlined.

The effect of heating rate, particle size and gas flow on the yield of charcoal during the pyrolysis of radiata pine wood

Charcoal derived from sustainable grown wood is a potential source of fuel and reductant for iron and steel making and a potential way to decrease the net CO2 emissions from the steelmaking industry. However a modern charcoal making process is likely to be required to supply the iron and steel industry with the required amount of charcoal to make significant difference to greenhouse gas emissions. The design of such a process requires fundamental knowledge on the effect of process variables on charcoal formation and yield during pyrolysis.The effect of biomass heating rate, purging gas flow and particle size on the yield of charcoal from pine wood was quantified in a series of pyrolysis experiments using a thermo-gravimetric apparatus. Temperature-time curves obtained during the heating of biomass showed the pyrolysis reactions became exothermic at about 350 °C. Increasing the flow of inert carrier gas through the biomass sample resulted in a decrease in charcoal yield and a faster rate of biomass decomposition. At zero gas flow the charcoal yield is independent of particle size. As gas flow through the sample is increased the yield of charcoal is increasingly dependent on increasing particle size.Increasing the wood heating rate from 0.11 to 10 °C/min, resulted in decreased charcoal yield. The period of fast biomass decomposition shifted to higher temperatures and the start of decomposition occurred at higher temperatures. These results indicate that low temperature reactions of charcoal formation are favoured by low heating rates and the initial charcoal acts as a catalyst for primary biomass decomposition. Lower heating rates are also associated with increased retention of pyrolysis vapours in the biomass which results is increased production of secondary charcoal and increased charcoal yield.

Nanostructure of Gasification Charcoal (Biochar).

In this work, we investigate the molecular composition and nanostructure of gasification charcoal (biochar) by comparing it with heat-treated fullerene arc-soot. Using ultrahigh resolution Fourier transform ion-cyclotron resonance and laser desorption ionization time-of-flight mass spectrometry, Raman spectroscopy, and high resolution transmission electron microscopy we analyzed charcoal of low tar content obtained from gasification. Mass spectrometry revealed no magic number fullerenes such as C60 or C70 in the charcoal. The positive molecular ion m/ z 701, previously considered a graphitic part of the nanostructure, was found to be a breakdown product of pyrolysis and not part of the nanostructure. A higher mass distribution of ions similar to that found in thermally treated fullerene soot indicates that they share a nanostructure. Recent insights into the formation of all carbon fullerenes reveal that conditions in charcoal formation are not optimal for the formation of fullerenes, but instead, curved carbon structures coalesce into fulleroid-like structures. Microscopy and spectroscopy support such a stacked, fulleroid-like nanostructure, which was explored using reactive molecular dynamics simulations.

Pile age and burn season influence fuelbed properties, combustion dynamics, fuel consumption, and charcoal formation when burning hand piles

Piling and burning is widely used to dispose of unmerchantable debris resulting from thinning in forests throughout the western United States. Quite often more piles are created than are burned in a given year, however, causing piles to persist, accumulate, and age on the landscape. The effects of burning piles of increasing age has not been studied. We examined the effects of time since construction (i.e., pile age, in roughly six month increments for two years) and burn season (fall and spring) on fuelbed properties, combustion dynamics, fuel consumption, and charcoal formation for hand-constructed piles in thinned ponderosa pine-dominated sites in New Mexico (n = 50 piles) and Washington (n = 49 piles). Piles compacted over time similarly for both study sites, losing approximately 15% of their height annually for the first two years following piling. Peak flame height decreased and the duration of flaming combustion increased with increasing pile age for both burn seasons in New Mexico, yet depended on burn season in Washington. Increasing fuel moisture and compaction reduced peak flame height and increased flaming duration modestly for both sites. Peak flame height was reduced 6–7 cm and flaming duration increased 0.9–2.3 min for every percentage increase in small fuel moisture. Similarly, peak flame height was reduced 4–5 cm and flaming duration increased 0.6–0.8 min for every percentage reduction in pile height. Fuel consumption was high, averaging 90% in New Mexico and 95% in Washington. Fuel consumption patterns differed between locations, however; fuel consumption decreased with age and was slightly higher for spring than fall burns in New Mexico, whereas, neither pile age nor burn season affected fuel consumption in Washington. Charcoal formation as a fraction of pre-burn pile weight averaged 2.8% in New Mexico and 1.2% in Washington, and was not affected by pile age or burn season. Fuel consumption and charcoal production were unaffected by fuel moisture or compaction levels at either site. Findings from this study will inform fuel and fire managers about the potential effects on fire behavior, fuel consumption, and charcoal formation of burning piles of different age in different seasons under different environmental conditions.

What Can Charcoal Reflectance Tell Us About Energy Release in Wildfires and the Properties of Pyrogenic Carbon?

Here we explore how charcoal formation under different heating regimes and circumstances leads to chars of different physical properties. In order to do this we have undertaken 1) carefully controlled laboratory experiments that replicate the different heating regimes that might be experienced during a wildfire and 2) two experimental wildfires where heat variations were monitored across the burn from which resulting charcoal has been studied. The charcoal properties were assessed using charcoal reflectance that measures the light reflected back from the charcoals structure and which links to changes in its structural properties. We find that increased total heat released during combustion positively correlates with increased charcoal reflectance and that this is evidenced from both our laboratory experiments and experimental wildfires. Charcoals that related to lower total heat release were found to have more lignin remaining than those subjected to greater heating indicating that charcoals formed in lower energy regimes are likely to be more susceptible to post-fire degradation. We conclude that charcoal reflectance may make a useful metric with which to determine the distribution of energy delivery across a burned area and that this may be utilised to inform both variations in fire severity and enable the prediction of long-term C budgeting for different types of wildfire.

Fire retardancy of an aqueous, intumescent, and translucent wood varnish based on guanylurea phosphate and melamine-urea-formaldehyde resin

Various concentrations of guanylurea phosphate (GUP) were incorporated into an aqueous melamine-urea-formaldehyde (MUF) resin to synthesize a fire-retardant, translucent, and intumescent varnish. The effects of the GUP on the curing, light transmittance, and thermal stability of the resulting varnish, and combustion behavior of the varnish-coated plywood were determined by viscosimetry, Fourier-transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV–vis) spectroscopy, thermogravimetry (TG), and cone calorimetry, respectively. The results show that GUP decelerated the curing rate; the resulting varnish film was translucent and UV-absorbing. The calorimetry demonstrated that GUP did not change the thermal stability but significantly facilitated charcoal formation of the varnish. The presence of the GUP resulted in an increased intumescent thickness of the varnish and substantially suppressed and delayed the mass loss, smoke production, and heat release of the coated plywood. At 12% GUP concentration the resulting varnish film exhibited an optimal combination of translucency and fire retardancy. These findings demonstrate that the GUP can be incorporated into aqueous MUF resin for the synthesis of a clear intumescent varnish capable of fire retardancy.

Evaluation of Ligno Boost™ softwood kraft lignin epoxidation as an approach for its application in cured epoxy resins

In this study, modification of LignoBoost™ softwood kraft lignin with epichlorhydrin in water-organic solvents media was realized. Lignin-based epoxy resins were obtained by two ways: acetone extraction of glycidylated lignin or glycidylation of the acetone soluble lignin fraction. The effect of glycidylation regimes on the yields of acetone soluble fractions, their functional composition and physical-chemical characteristics was investigated using wet chemistry methods, FTIR spectroscopy, size exclusion chromatography (SEC) and differential scanning calorimetry (DSC). The positive effect of the biphasic phase transfer catalytic system – KOH/quaternary ammonium salt – on glycidylation of both phenolic and aliphatic hydroxyl groups was testified, exemplified using a lignin-like model compound – 4-hydroxy-3-methoxylbenzyl alcohol (vanillyl alcohol). The partial substitution (up to 10%) of commercial epoxy resin on the basis of bisphenol A (Araldite® LY1564) by lignin-based epoxy resin significantly increased the viscosity of resin. Therefore, the possible practical application of lignin-containing epoxies as adhesive, mastic or crack filler instead of binder for fiber reinforced composites was considered. A tendency towards increasing Young’s modulus of cured lignin-containing epoxies, compared with the case of the reference composition, was observed. The lignin chemically incorporated into the matrix of cured commercial epoxy resin acts as a charcoal formation promoter in high temperature treatment.

Macroscopic charcoal remains as evidence of wildfire from late Permian Gondwana sediments of India: Further contribution to global fossil charcoal database

Although there have been numerous reports of the occurrence of charcoal from the Indian Permian sediments (Kashmir and the Domodar Basin), here we report a new occurrence of charcoal from the Lopingian sediments of Central India, which is evidence of wildfire occurrence in the Permian of Gondwana and an addition to the global fossil charcoal database. Charcoal, a product of incomplete combustion of vegetation, is extensively reported from the Permian sediments of southern and northern hemisphere. Numerous reports have been generated from palaeobotanical and petrographical aspects of Gondwana sediments of India but the presence of macroscopic fossil charcoal has been somewhat overlooked until the past few years by many researchers, though the fusinite (charcoal equivalent term in petrographical studies) from many coalfields of Indian Gondwana has been attributed to pyrogenitic origin. Our study was carried out on macroscopic charcoal fragments retrieved from an exploratory drill core MBKW-3 from Mand-Raigarh Coalfield in the central part of the Mahanadi Basin, eastern India. The analysis involved Scanning Electron Microscopy for study of anatomical features and reflecting microscopy for estimation of the temperature of fire of charcoal formation where the inertinite reflectance data (average of 3.33%) indicate that these charcoals are formed at a temperature above 500°C. Palynomorph composition and their probable botanical affinity indicate that gymnosperms were the major type of vegetation that contributed to fuel load for wildfire while pteridophytes constituted a minor proportion. The palynological data reveal the predominance of arborescent vegetation over herbaceous elements. Fusinite reflectance data indicate that these charcoals are formed at a temperature in excess of 500°C. The almost unabraded edges of these charcoals, their high degree of preservation, and an assorted assemblage of different sizes clearly indicate their hypoautochtonous nature.

Observations of the structural changes that occur during charcoalification: implications for identifying charcoal in the fossil record

AbstractAll of our current understanding of fossil charcoal structure comes from observations of modern wood charcoal produced in furnaces. These charcoals consistently show cell wall homogenization after prolonged heating (>325°C) and this is therefore considered to be a key identifying feature of fossil charcoal. Yet furnaces are unable to replicate the full combustion processes that occur during a wildfire. Here, for the first time, we have studied the microscopic structural evolution of charcoal produced using calorimetry, wherein the wood is ignited under controlled conditions and the heat release rate and other parameters measured, and the resulting charcoal studied using reflected light microscopy. We show that homogenization of cell walls is actually only a short‐lived phase of charcoal formation that occurs during the early heating stages as the pyrolysis front traverses through the wood. Cell wall homogenization is then rapidly overprinted by the thinning, distortion and breakdown of cell walls, and a notable visual increase in reflectance. Our preliminary study therefore suggests that we need to first improve our understanding of charcoal formation in order to better understand the fossil record of wildfires.

Exploring the application potential of incompletely soluble organosolv lignin as a macromonomer for polyurethane synthesis

A new type of organosolv wheat straw lignin, so-called Biolignin™, was studied. It is obtained according to the biomass processing in water diluted organic acid media and is not completely soluble in conventional organic solvents traditionally applied for polyurethanes (PU) synthesis. The fractionation of the lignin by sequential extraction with dichloromethane, methanol and a mixture of both solvents was performed. The total yield of the separated soluble fractions was 40%. The separated fractions were characterized, and preliminary kinetic investigations were used to reveal the reactivity of fractions obtained towards 4,4′-methylene diphenylene diisocyanate (MDI) in dioxane media. PU films were synthesized by casting the three component systems: lignin fraction – polyethylene glycol with a molecular weight of 400gmol−1 – polymeric methyl diisocyanate prepolymerized in tetrahydrofurane solution at a constant NCO/OH ratio of 1.05. The content of lignin in PU compositions was varied in a range of 5–40%. The PU films were characterized in terms of crosslink density, tensile properties, glass transition temperature and thermal stability. The obtained results show that the isolated fractions of Biolignin™ act as a crosslinking macromonomer in the PU network. Depending on the lignin fraction type and its content in the composition, the tensile properties of PU films with a high elastic state at room temperature or the tensile properties of glassy cross-linked films were obtained. Evidence for the activity of lignin fractions as antioxidants of PU compositions and charcoal formation promoters in the case of the high temperature treatment of PU in air was obtained.

Biomimetic Fenton-catalyzed lignin depolymerization to high-value aromatics and dicarboxylic acids.

By mimicking natural lignin degradation systems, the Fenton catalyst (Fe(3+), H2O2) can effectively facilitate lignin depolymerization in supercritical ethanol (7 MPa, 250 °C) to give organic oils that consist of mono- and oligomeric aromatics, phenols, dicarboxylic acids, and their derivatives in yields up to (66.0±8.5) %. The thermal properties, functional groups, and surface chemistry of lignin before and after Fenton treatment were examined by thermogravimetric analysis, pyrolysis-gas chromatography-mass spectrometry, (31)P NMR spectroscopy, and X-ray photoelectron spectroscopy. The results suggest that the Fenton catalyst facilitates lignin depolymerization through cleavage of β-ether bonds between lignin residues. The formation of a lignin-iron chelating complex effectively depresses lignin recondensation; thus minimizing charcoal formation and enhancing the yield of liquid products.

PROSES ADSORPSI SENYAWA LINIER ALKILBENZENE SULFONAT (LAS) MELALUI ARANG AKTIF KULIT UBI KAYU

This research aims was to analyze the potential of activated charcoal leather cassava in the adsorption process linear compounds alkilbenzene sulfonate (LAS) contained in the liquid waste household detergents. Stages of the study consisted of charcoal formation process of the skin of cassava through the combustion process of pyrolysis, charcoal leather activation process cassava, and the compound adsorption process linear alkyl sulfonate (LAS) contained in the liquid waste household detergents. The results showed that activated charcoal is formed from leather waste cassava LAS have the ability to adsorb the compounds contained in domestic wastewater. Treatment optimum adsorption occurs at a concentration of activated charcoal leather cassava 4 grams and a contact time of 20 minutes.

Vegetation dieback as a proxy for temperature within a wet pyroclastic density current: A novel experiment and observations from the 6th of August 2012 Tongariro eruption

The 6th of August 2012 eruption of Te Maari (Mt Tongariro, New Zealand) generated wet pyroclastic density currents (PDCs) which caused widespread dieback of vegetation (singed, brown foliage) in their path. An absence of significant charcoal formation suggests that PDC temperatures were mostly below 250°C. Textural evidence for liquid water being present in the matrices during emplacement (vesicles) suggests that temperatures were <100°C. We determined a probable minimum PDC temperature using an experiment replicating the critical temperatures required to induce foliar browning in seven species affected by the eruption. In locations where all species exhibited browned foliage (or were defoliated), temperatures were probably ≥64°C assuming a PDC duration of 60s. In the more distal areas, where only the most susceptible species were browned while others remained healthy and unaffected, temperatures were probably around 51–58°C. These results have relevance to volcanic hazard mitigation and risk assessment, especially on the popular Tongariro Alpine Crossing.

REVIEW: Charcoal function and management in boreal ecosystems

Summary Charcoal plays an important role in soil function and carbon storage in fire‐prone ecosystems. Charcoal is present in most boreal forest soils as a result of naturally recurring wildfires, which convert 0·7–2% of biomass to charcoal. In boreal forests, charcoal represents 8–10% of soil carbon and 1 pg of carbon globally. Charcoal is resistant to decay, representing a form of super‐passive carbon, with half‐lives one to two orders of magnitude greater than those of other soil organic matter. High concentrations of negative surface charges increase nutrient retention, impacting boreal soil function, productivity and species composition. Due to a lack of soil mixing processes, charcoal in boreal soils is vulnerable to recombustion in recurring fires, inhibiting the accumulation of charcoal over time, unlike in other fire‐prone ecosystems. Boreal charcoal stocks are highly variable. Increased fire intensity results in greater charcoal formation, with stand‐replacing crown fires resulting in much larger charcoal stocks than non‐stand‐replacing ground fires. Current estimates of carbon storage based on Scandinavian studies of non‐stand‐replacing fires may underestimate charcoal stocks by factors of 2–3. Synthesis and applications. Charcoal contributes to boreal soil function, ecosystem productivity, nutrient retention and carbon cycling. In the absence of fire, charcoal loses many active properties, contributing to declining productivity with increasing time since fire. Incorporation of charcoal into ecosystem management using prescribed burns may contribute to sustainable management of boreal forests and maintaining global carbon cycles.

Towards reconstruction of past fire regimes from geochemical analysis of charcoal

Production of charcoal has accompanied human life from the beginning. We aimed at evaluating the degree to which the chemical signatures of charcoal may serve as a fingerprint for burning conditions. After a compilation of fire literature we differentiated three typical fire regimes [grass and forest ground (285±143°C), shrub (503±211°C) and domestic fires (797±165°C)] and three main factors impacting on charcoal formation: charring duration, temperature and fuel. For fingerprint calibration and validation, typical fuels of prehistoric burning events (wood and grass) were charred under laboratory conditions (300–700°C; varying duration) and compared with residues from natural fires in SE Europe. Analysis comprised assessment of benzene polycarboxylic acids (BPCAs), organic carbon (Corg) content, nitrogen content, oxygen index (OI, CO2/Corg) and hydrogen index (HI, HC/Corg), temperature of maximum heating (Tmax) and mid-infrared spectroscopy (MIRS). All parameters including mass loss increased with increasing combustion temperature, but were unaffected by charring duration. Grass charcoal had consistently lower Corg content and HI than wood, but values showed a bias towards the natural charcoals, probably because the latter contained higher amounts of mineral matter or were combusted under greater O2 supply. Nevertheless, natural charcoals could be differentiated into forest ground fires (B5CA/B6CA 1.3–1.9; OI>20; intense CH2 stretching, Tmax<488°C) and grass fires (B5CA/B6CA 0.8–1.4; OI>20; weak CH2 stretching, Tmax<425°C), whereas domestic fires revealed B5CA/B6CA values <0.8, OI values <20 and little MIRS absorbance. In summary, it appears possible to reconstruct fire regimes from the temperature sensitivity of BPCA patterns, Tmax, OI and aromatic and aliphatic MIRS signals, whereas assignment of fuel source was less reliable.

Long and Short-Term Effects of Fire on Soil Charcoal of a Conifer Forest in Southwest Oregon

In 2002, the Biscuit Wildfire burned a portion of the previously established, replicated conifer unthinned and thinned experimental units of the Siskiyou Long-Term Ecosystem Productivity (LTEP) experiment, southwest Oregon. Charcoal C in pre and post-fire O horizon and mineral soil was quantified by physical separation and a peroxide-acid digestion method. The abrupt, short-term fire event caused O horizon charcoal C to increase by a factor of ten to >200 kg C ha−1. The thinned wildfire treatment produced less charcoal C than unthinned wildfire and thinned prescribed fire treatments. The charcoal formation rate was 1 to 8% of woody fuels consumed, and this percentage was negatively related to woody fuels consumed, resulting in less charcoal formation with greater fire severity. Charcoal C averaged 2000 kg ha−1 in 0–3 cm mineral soil and may have decreased as a result of fire, coincident with convective or erosive loss of mineral soil. Charcoal C in 3–15 cm mineral soil was stable at 5500 kg C ha−1. Long-term soil C sequestration in the Siskiyou LTEP soils is greatly influenced by the contribution of charcoal C, which makes up 20% of mineral soil organic C. This research reiterates the importance of fire to soil C in a southwestern Oregon coniferous forest ecosystem.