Proportion Of Charcoal Research Articles

Proportion of charcoal carbon in the forest floor carbon pool in relation to fire history in a boreal forest landscape

AbstractFire in the boreal forests emits substantial amounts of organically bound carbon (C) to the atmosphere and converts a fraction of the burnt organic matter into charcoal, which in turn is highly refractory and functions as a long‐term stable C pool. It is well established that the boreal forest charcoal pool is sufficiently large to play a significant role in the global C cycle. However, there is a need for spatially representative estimates of how large proportions of the forest floor C pool are made up of charcoal across different plant communities in the boreal forest ecosystem. Thus, we have quantified the amounts of C separately in charcoal and the organic layers of the forest floor across fine spatial scales in a boreal forest landscape with a well‐documented fire history. We found that the proportion of charcoal C made up an average of 1.2% of the total forest floor C, and the charcoal proportions showed a high small‐scale spatial variability and were concentrated in the organic–mineral soil interface. Proportions of charcoal C decreased with increasing time since last fire. Deeper soils, denser soils, and local concave areas had the highest proportions of charcoal C, whereas historical fire frequencies and current differences in vegetation did not relate to the proportions of charcoal C.

A Holocene history of forest vegetation on the northern slopes of a Mediterranean mountain: the Mont Ventoux, Southeast France / Histoire holocène de la végétation forestière du versant nord d’une montagne méditerranéenne : le mont Ventoux (Vaucluse, France)

This study aims at reconstructing the late Holocene vegetation dynamics and the maximum altitudinal limit of forest trees on northern slopes of Mont Ventoux before the intense deforestation of the 12th century, in relation to natural environmental changes and anthropogenic disturbances including fire history and sylvo-pastoral practices. Six soil pits were studied out along an altitudinal transect from 925m to 1,860m a. s. l. This transect crosses the beech-fir forests in the lower elevations to open woodlands containing the prostrate hooked pine (Pinus uncinata) near the summit. The study was performed within the framework of the ecological monitoring program ORCHAMP. Pedoanthracological data (identified charcoals and their 14C ages) were further explored by numerical analyses. Charcoal was found in all pits with concentrations significantly decreasing with altitude, as does the proportion of charcoal of deciduous trees over conifers. Some woody species were found at altitudes where they are absent today, notably fir (Abies alba) at high elevations, (up to 1,860m). In contrast to fir, the beech (Fagus sylvatica) charcoals were not found beyond 1,340m, although the species currently reaches elevations as high as 1,700m a. s. l. Radiocarbon dating results suggest that the soils on northern slopes of Mont Ventoux have not been significantly eroded since at least 4,000 years ago. The period covered by the six obtained AMS 14C dates extends from the Bronze Age (oldest 14C age : 3576-3729 cal BP / 1779-1626 BCE) to the Modern Era (youngest 14C age : 346-460 cal BP / 1490-1604 CE), all pre-dating the 1860’ s reforestation projects (RTM, Restoration of Mountain Land). This preliminary pedoanthracological study proved to be promising and complementary to other palaeoecological approaches but is still insufficient to provide a complete picture of the past vegetation history of Mont Ventoux.

Charcoal Use in Chromite Pellets − Effect on Sintering Process, Pellet Properties, and Electrical Conductivity

Ferrochrome is produced by carbothermic reduction of chromite raw materials. Chromite fines need to be agglomerated before they can be utilized. Typically, chromite fines are fed to the smelting furnace in a form of sinter or sintered pellets. Sintering requires high temperatures, which is generated by burning carbon‐bearing materials. Usually, coke is used as a fuel in chromite pellet sintering, which results in SOX and CO2 emissions. Using low‐sulfur biofuel to substitute coke is an attractive technique for reducing SOX and CO2. In this paper, coke substitution with charcoal in chromite pellet sintering is studied. The results show that coke substitution with charcoal affects the sintering behavior, cold compression strength, and electrical conductivity of the chromite pellets. The suitable replacing proportion of charcoal according to studies made in this paper will be 50%.

Soil charcoal prediction using attenuated total reflectance mid-infrared spectroscopy

Despite strong evidence for the importance of charcoal as a long-term carbon sink in soils, simple methods to quantify charcoal in soil are still lacking. In this study, we tested the application of attenuated total reflectance mid-infrared spectroscopy (ATR-MIR) for quantification of charcoal in soil. To do this, we created calibration samples from defined quantities of pulverised rock, charcoal and litter sampled from a forest floor in Guy Fawkes National Park, New South Wales, Australia, and analysed them via ATR-MIR and dry combustion. The organic carbon concentration (mass proportion) of the samples ranged from 0.1 to 15% and the charcoal mass proportion from 0.02–11% (10–50% of soil organic matter). We then trained randomForest models to the spectral data and assessed the predictive performance of the models for both the quantity of charcoal and litter in the samples. The models were excellent at predicting both charcoal and litter contents of the samples, explaining 94% of variance in the mass proportion of charcoal and 93% of the variance in the litter content of the validation dataset (i.e. out-of-bag estimates of the models). Extracting the variable importance from the models showed that the spectral regions important to charcoal prediction differed from those important to litter prediction, highlighting the capacity of the models to distinguish between charcoal and litter components based upon ATR-MIR spectra. Our method enables a simple, cheap and efficient prediction of litter and charcoal without the need for complex chemical extraction or analyses.

Palynostratigraphy of dinosaur footprint-bearing deposits from the Triassic–Jurassic boundary interval of Sweden

The Triassic–Jurassic boundary (c. 200 Ma) marks one of the five largest Phanerozoic mass extinction events and is characterized by a major turnover in biotas. A palynological study of sedimentary rock slabs bearing dinosaur footprints from Rhaeto–Hettangian strata of Skåne, Sweden was carried out. The theropod dinosaur footprints (Kayentapus soltykovensis) derive from the southern part of the abandoned Vallåkra quarry (Höganäs Formation) and were originally dated as earliest Jurassic (Hettangian) based on lithostratigraphy. Our results reveal that two of the footprints are correlative with the latest Triassic (latest Rhaetian) disaster zone typified by a high abundance of the enigmatic gymnosperm pollen Ricciisporites tuberculatus and Perinopollenites elatoides together with the key taxon Limbosporites lundbladii and fern spores. Two footprints are dated to correlate with the Transitional Spore-spike Interval. One footprint is interpreted as Hettangian in age based on the relatively high abundance of Pinuspollenites spp. together with the presence of the key taxa Retitriletes semimuris and Zebrasporites intercriptus. Our new palynological study suggests that the Kayentapus ichnogenus already appeared in the end of Triassic, and our study highlights the use of palynology as a powerful tool to date historical collections of fossils in museums, universities and elsewhere. The Hettangian footprint reflects a marine influence while all other studied ichnofossil specimens occur in non-marine (floodplain and delta interdistributary) sediments. The sediments associated with the Hettangian footprint include a significant proportion of charcoal transported from land after wildfires. The Rhaeto–Hettangian vegetation was otherwise characterized by multi-storey gymnosperm–pteridophyte communities.

Minor changes in soil organic carbon and charcoal concentrations detected in a temperate deciduous forest a year after an experimental slash-and-burn

Abstract. Anthropogenic fires affected the temperate deciduous forests of Central Europe over millennia. Biomass burning releases carbon to the atmosphere and produces charcoal, which potentially contributes to the stable soil carbon pools and is an important archive of environmental history. The fate of charcoal in soils of temperate deciduous forests, i.e. the processes of charcoal incorporation and transportation and the effects on soil organic matter are still not clear. We investigated the effects of slash-and-burn at a long-term experimental burning site and determined soil organic carbon and charcoal carbon concentrations as well as the soil lightness of colour (L*) in the topmost soil material (0–1, 1–2.5 and 2.5–5 cm depths) before, immediately after the fire and one year later. The main results are that (i) only a few of the charcoal particles from the forest floor were incorporated into the soil matrix, presumably by soil mixing animals. In the 0–1 cm layer, during one year, the charcoal C concentration increased only by 0.4 g kg−1 and the proportion of charcoal C to SOC concentration increased from 2.8 to 3.4%; (ii) the SOC concentrations did not show any significant differences; (iii) soil lightness decreased significantly in the topmost soil layer and correlated well with the concentrations of charcoal C (r=−0.87**) and SOC (r=−0.94**) in the samples from the 0–5 cm layer. We concluded that Holocene biomass burning could have influenced soil charcoal concentrations and soil colour.