@misc{RaabHirschOuimetetal., author = {Raab, Thomas and Hirsch, Florian and Ouimet, William and Johnson, Katharine M. and Dethier, David and Raab, Alexandra}, title = {Architecture of relict charcoal hearths in northwestern Connecticut, USA}, series = {Geoarchaeology}, volume = {32}, journal = {Geoarchaeology}, number = {4}, issn = {1520-6548}, doi = {10.1002/gea.21614}, pages = {502 -- 510}, abstract = {Relict charcoal hearths are round or elliptical earthen platforms up to 11 m in diameter and a widespread feature of historical industry that supplied charcoal used in the production of iron in furnaces or smelters. The iron industry dominated Litchfield County, Connecticut, and surrounding areas in the northeastUnited States throughout the 19th century, peaking in ∼1850. The large number of charcoal hearths in this region is a relic of >150 years of widespread iron production. In this study, we describe the architecture and soil stratigraphy of 26 charcoal hearths in Litchfield County. This contribution aims to (1) compare soils that comprise the charcoal hearths with "natural" adjacent soils, (2) measure the thickness of topsoil developed upon the hearths, and (3) characterize the stratigraphy associated with these features. Results indicate that the black topsoils overlying the charcoal hearths contain residual charcoal and are on average 2.6 times thicker than adjacentCambisols. Charcoal hearths display two ormore black, charcoal-rich strata separated by layers of reddish-brown soil low in charcoal content indicating multiple episodes of use.We also find that many charcoal hearths have been stabilized with boulders on the downslope side during construction and repeated use.Overall, the results presented here provide significant information regarding the construction, use, and associated impacts of earthen platforms for charcoal production in the northeastUnited States, with further relevance to other areas where historical charcoal production occurred.}, language = {en} } @inproceedings{HirschSchneiderRaabetal., author = {Hirsch, Florian and Schneider, Anna and Raab, Alexandra and Raab, Thomas and Ouimet, William and Dethier, David}, title = {Late Holocene biochar enrichment in soils - implications of an anthropogenic legacy for ecosystems}, series = {ICLEA Final Symposium 2017, Human Impact and Landscape Evolution in the Southern Baltic Lowlands, Abstract Volume \& Excursion Guide}, booktitle = {ICLEA Final Symposium 2017, Human Impact and Landscape Evolution in the Southern Baltic Lowlands, Abstract Volume \& Excursion Guide}, editor = {Schwab, Markus and Błaszkiewicz, Mirek and Raab, Thomas and Wilmking, Martin and Brauer, Achim}, publisher = {GFZ German Research Centre for Geosciences}, address = {Potsdam}, doi = {10.2312/GFZ.b103-17037}, pages = {79 -- 81}, language = {en} } @misc{HirschRaabOuimetetal., author = {Hirsch, Florian and Raab, Thomas and Ouimet, William and Dethier, David and Schneider, Anna and Raab, Alexandra}, title = {Soils on Historic Charcoal Hearths: Terminology and Chemical Properties}, series = {Soil Science Society of America, International Soils Meeting, Soils Across Latitudes, San Diego 2019}, journal = {Soil Science Society of America, International Soils Meeting, Soils Across Latitudes, San Diego 2019}, language = {en} } @misc{BonhageMykhailovaHirschetal., author = {Bonhage, Alexander and Mykhailova, Larysa and Hirsch, Florian and Schneider, Anna and Raab, Thomas and Fischer, Thomas and Raab, Alexandra and Donovan, Sally and Ouimet, William}, title = {Effects of historical charcoal burning on soil landscapes in West Connecticut - Quantifying pyrogenic and organic soil carbon content of Technosols by FTIR analysis}, series = {European Geosciences Union, General Assembly 2019, Vienna, Austria, 7-12 April 2019}, journal = {European Geosciences Union, General Assembly 2019, Vienna, Austria, 7-12 April 2019}, address = {Katlenburg-Lindau}, language = {en} } @misc{BonhageRaabRaabetal., author = {Bonhage, Alexander and Raab, Thomas and Raab, Alexandra and Schneider, Anna and Ramezany, Shaghayegh and Ouimet, William}, title = {Pyrogenic carbon in temperate forests - long-lasting impact of historical charcoal production on soils and ecosystems}, series = {EGU General Assembly 2022, Vienna, Austria, 23-27 May 2022}, journal = {EGU General Assembly 2022, Vienna, Austria, 23-27 May 2022}, doi = {10.5194/egusphere-egu22-8312}, abstract = {Pre- and early industrial charcoal production has left a striking legacy effect on today's soil landscapes in many forests of Central Europe and the North Eastern USA. Charcoaling in upright standing hearths (also called kilns) resulted in distinct circular micro relief structures, easily identifiable today in the field and on high resolution LiDAR-based digital elevation maps. Soils on these sites are characterized by one or multiple layers of decimetre thick charcoal rich substrate, which makes them Spolic Technosols according to the WRB soil classification. The focus of research on these sites increasingly deals with the difference of their soil physical and chemical properties in relation to unaffected forest soils and the potential implications for changes in vegetation and faunal growth. The controlling factor thereby is the soils large content of charcoal in various particle sizes, ranging from fine dust to large chunks. Studies have repeatedly shown the soils significant increase in total organic- and pyrogenic carbon content. The increase in total carbon stocks is thereby not only caused by pyrogenic carbon, but also by an apparently increased accumulation of non-pyrogenic organic matter. Here we present the latest findings regarding the carbon contents of centennially old charcoal rich technogenic substrates, sampled as part of multiple research projects in Brandenburg, Germany and the Litchfield hills in North-western Connecticut, USA. A focus will be the determination of highly aromatic carbon by the molecular marker Benzene-polycarboxylic acid (BPCA) and its prediction by FTIR-MIR chemometric methods. We discuss the results on forest soil carbon stocks on a site specific to a landscape and regional scale. Furthermore, the potential to use these sites to study the long term effects of charcoal admixture to soils by wildfires or biochar application will be discussed.}, language = {en} } @misc{HirschRaabOuimetetal., author = {Hirsch, Florian and Raab, Thomas and Ouimet, William and Dethier, David and Schneider, Anna and Raab, Alexandra}, title = {Soils on historic charcoal hearths - terminology and chemical properties}, series = {Soil Science Society of America Journal : SSSAJ}, volume = {81}, journal = {Soil Science Society of America Journal : SSSAJ}, number = {6}, issn = {1435-0661}, doi = {10.2136/sssaj2017.02.0067}, pages = {1427 -- 1435}, abstract = {Historic charcoal hearth remains provide a unique archive of the long term interaction between biochar, soil development and plant growth. Charcoal as raw material was crucial for production of iron in iron works and hence numerous charcoal hearths can be found in the forests near historic iron works in Europe as well as the Eastern United States. Charcoal hearths are round to elliptical forms often around 10 m in diameter, and consist of several decimeter thick layers that contain charcoal fragments, ash, and burnt soil. We studied the soil chemistry of 24 charcoal hearths and compared them to the surrounding 'natural' soils in the northern Appalachians of northwestern Connecticut. The thickness of the topsoils on the charcoal hearths and their carbon content are remarkably higher than in the surrounding topsoils. The presence of residual products from charcoal production classifies the soils as Anthropic Udorthents (US Soil Taxonomy) or Spolic Technosols (Humic) according to the World Reference Base for Soil Resources. The widespread occurrence of charcoal hearth remains and their high spatial density in different ecosystems underlines their importance for further pedological research.}, language = {en} } @misc{BonhageMykhailovaHirschetal., author = {Bonhage, Alexander and Mykhailova, Larysa and Hirsch, Florian and Schneider, Anna and Raab, Thomas and Raab, Alexandra and Ouimet, William}, title = {FTIR-based inquiry on carbon in forest soil substrate enriched by aged biochar, West Connecticut, USA}, series = {Jahrestagung der Bodenkundlichen Gesellschaft der Schweiz und der Deutschen Bodenkundlichen Gesellschaft, Abstract-Band 2019}, journal = {Jahrestagung der Bodenkundlichen Gesellschaft der Schweiz und der Deutschen Bodenkundlichen Gesellschaft, Abstract-Band 2019}, pages = {S. 198}, abstract = {Relict charcoal hearths (RCHs) are sites of former charcoal production that are an increasingly well documented anthropogenic feature in forests of the temperate climate zone. However, the type and extent of a possible legacy effect from RCHs on soil physical and chemical properties is still largely unknown. In the Litchfield Hills in west Connecticut, RCH sites are located mainly on slopes and therefore differ in their architecture from lowland sites found in Europe. One of the striking characteristics of a RCH site regardless of its architecture is the enrichment of the soil with charcoal in varying particle sizes. In this study, we use chemical digestion coupled with a PLSR-model to quantify organic carbon and pyrogenic carbon in RCH substrate by MIR-DRIFT measurements. Furthermore, we analyse the quality of carbon compounds by MIR-DRIFT measurements on multiple grain size fractions to assess the post-burn enrichment of soil organic matter. Preliminary results show a markedly increase in organic and pyrogenic carbon in RCH substrates in relation to the natural forest soil. Also, our first results suggest that the enrichment of organic carbon is favoured on RCHsites. However, the causality between the enrichment of soil organic matter and site features remains open. Experiments using chemical extraction techniques on our samples hint at an increase of labile organic compounds and/or microbial biomass. This legacy effect of RCHs is however evident and further studies need to focus on how to address them.}, language = {de} } @misc{BonhageHirschSchneideretal., author = {Bonhage, Alexander and Hirsch, Florian and Schneider, Anna and Raab, Thomas and Raab, Alexandra and Ouimet, William and Drohan, Patrick J.}, title = {Effects of Historical Charcoal Burning on Soil Landscapes in West Connecticut, USA}, series = {Soil Science Society of America, International Soils Meeting, Soils Across Latitudes, San Diego 2019}, journal = {Soil Science Society of America, International Soils Meeting, Soils Across Latitudes, San Diego 2019}, language = {en} } @misc{BonhageHirschRaabetal., author = {Bonhage, Alexander and Hirsch, Florian and Raab, Thomas and Schneider, Anna and Raab, Alexandra and Ouimet, William}, title = {Characteristics of small anthropogenic landforms resulting from historical charcoal production in western Connecticut, USA}, series = {Catena}, volume = {195}, journal = {Catena}, issn = {0341-8162}, doi = {10.1016/j.catena.2020.104896}, pages = {14}, language = {en} } @misc{BonhageRaabSchneideretal., author = {Bonhage, Alexander and Raab, Thomas and Schneider, Anna and Fischer, Thomas and Ramezany, Shaghayegh and Ouimet, William and Raab, Alexandra and Hirsch, Florian}, title = {Vertical SOC distribution and aromatic carbon in centuries old charcoal-rich Technosols}, series = {European Journal of Soil Science}, volume = {73}, journal = {European Journal of Soil Science}, number = {4}, doi = {10.1111/ejss.13293}, pages = {1 -- 16}, abstract = {Charcoal-rich Technosols on century-old relict charcoal hearths (RCHs) are the subject of ongoing research regarding potential legacy effects that result from historic charcoal production and subsequent charcoal amendments on forest soil properties and forest ecosystems today. RCHs consist mostly of Auh horizons that are substantially enriched in soil organic carbon (SOC), of which the largest part seems to be of pyrogenic origin (PyC). However, the reported range of SOC and PyC contents in RCH soil also suggests that they are enriched in nonpyrogenic SOC. RCH soils are discussed as potential benchmarks for the long-term influence of biochar amendment and the post-wildfire influences on soil properties. In this study, we utilised a large soil sample dataset (n = 1245) from 52 RCH sites in north-western Connecticut, USA, to quantify SOC contents by total element analysis. The contents of condensed highly aromatic carbon as a proxy for black carbon (BC) were predicted by using a modified benzene polycarboxylated acid (BPCA) marker method in combination with diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy-based partial least square regression (r2 = 0.89). A high vertical spatial sampling resolution allowed the identification of soil organic matter (SOM) enrichment and translocation processes. The results show an average 75\% and 1862\% increase in TOC and BPCA-derived carbon, respectively, for technogenic Auh horizons compared to reference soils. In addition to an increase in aromatic properties, increased carboxylic properties of the RCH SOC suggest self-humification effects of degrading charcoal and thereby the continuing formation of leachable aromatic carbon compounds, which could have effects on pedogenic processes in buried soils. Indeed, we show BPCA-derived carbon concentrations in intermediate technogenic Cu horizons and buried top/subsoils that suggest vertical translocation of highly aromatic carbon originating in RCH Auh horizons. Topmost Auh horizons showed a gradual decrease in total organic carbon (TOC) contents with increasing depth, suggesting accumulation of recent, non-pyrogenic SOM. Lower aliphatic absorptions in RCH soil spectra suggest different SOM turnover dynamics compared to reference soils. Furthermore, studied RCH soils featured additional TOC enrichment, which cannot be fully explained now.}, language = {en} } @inproceedings{BonhageRaabOuimetetal., author = {Bonhage, Alexander and Raab, Thomas and Ouimet, William and Raab, Alexandra}, title = {Effects of historical charcoal burning on soil landscapes in West Connecticut, USA}, series = {European Geosciences Union, General Assembly 2018, Vienna, Austria}, booktitle = {European Geosciences Union, General Assembly 2018, Vienna, Austria}, publisher = {European Geophysical Society}, address = {Katlenburg-Lindau}, language = {en} } @inproceedings{HirschRaabOuimetetal., author = {Hirsch, Florian and Raab, Thomas and Ouimet, William and Dethier, David and Schneider, Anna and Raab, Alexandra}, title = {Soils on historic charcoal hearths - chemical properties and terminology}, series = {European Geosciences Union, General Assembly 2017, Vienna, Austria}, booktitle = {European Geosciences Union, General Assembly 2017, Vienna, Austria}, publisher = {European Geophysical Society}, address = {Katlenburg-Lindau}, url = {http://nbn-resolving.de/http://meetingorganizer.copernicus.org/EGU2017/EGU2017-4009-1.pdf}, abstract = {Charcoal hearths are a unique archive for the long term interaction between biochar, soil development and plant growth. Charcoal as raw material was crucial for the production of iron in iron works and hence numerous charcoal hearths can be found in the forests near historic iron works in Europe as well as the Eastern United States. Charcoal hearths are round to elliptical forms often around 10 m in diameter, and consisting of a several decimeter thick layer containing charcoal fragments, ash, and burnt soil. We studied the soil chemistry of 24 charcoal hearths and compared them to the surrounding 'natural' soils in Litchfield County, Connecticut. The thickness of the organic rich horizons on the charcoal hearths and their carbon content is remarkably higher than in the surrounding topsoils. The wide distribution of charcoal hearths, their usually high quantity, and their occurrence in different ecosystems underlines their importance for further pedological research.}, language = {en} } @inproceedings{RaabHirschOuimetetal., author = {Raab, Thomas and Hirsch, Florian and Ouimet, William and Dethier, David}, title = {Soil stratigraphy of charcoal kiln remains (CKR) in the Litchfield Hills, CT, USA}, series = {European Geosciences Union, General Assembly 2016, Vienna, Austria}, booktitle = {European Geosciences Union, General Assembly 2016, Vienna, Austria}, publisher = {European Geophysical Society}, address = {Katlenburg-Lindau}, abstract = {Charcoal kiln relicts (CKRs) are small anthropogenic landforms that are often found in historic mining areas. CKRs have not been a big research topic yet but mainly were studied as by-products of archaeological excavations. In the last years newly available and very accurate Digital Elevation Models (DEMs) based on high-resolution Airborne Laser Scanning (ALS) data have been used to identify these archaeological remains. In addition, findings of several thousands CKRs in the North German Lowland have increased the awareness that historical charcoal production may significantly contribute to Late Holocene landscape change. Besides the archaeological aspect of CKRs, potential impacts of charcoal burning on the ecology of modern soil landscapes and ecosystem processes must be considered. A relatively high density of CKRs is found in the Litchfield Hills nearby the town of West Cornwall, Litchfield County, CT, USA. The CKRs are especially well preserved on slopes of the tributary valleys of the Housatonic River and form little, circular ramparts with diameters normally less than ten meters. First, rough field surveys in Litchfield County in spring 2015 have suggested differences between soils inside and outside the CKR. Soils on the CKR seem to have relatively deep humus-rich and charcoal containing topsoils whereas the topsoils outside the CKR appear typically thinner and less rich in humus. More thorough investigations have been started in autumn 2015 to prove the hypothesis that properties, distribution and development of soils are controlled by archaeological remains of historical charcoal burning. We present preliminary results from our field studies conducted in October 2015. The stratigraphy and the extent of the 26 CKRs were studied using a sedimentological-pedological approach by coring and trenching. Our results indicate that in Litchfield County the CKRs were used twice and in quick succession. Before the second reuse, the rim of the platform was stabilized with boulders. The black topsoils on the CKRs contain residual charcoal and the topsoils are thicker compared to the soil sequences outside of the CKRs.}, language = {en} } @misc{BonhageHirschRaabetal., author = {Bonhage, Alexander and Hirsch, Florian and Raab, Thomas and Schneider, Anna and Raab, Alexandra and Ouimet, William}, title = {Stratigraphy and shape of relict charcoal hearths in Connecticut, USA}, series = {Anthropogenetische Geomorphologie - Geomorophologie im Anthropoz{\"a}n : Virtuelle Jahrestagung des Arbeitskreises f{\"u}r Geomorphologie 2020, 28./29. September 2020, BTU Cottbus - Senftenberg}, journal = {Anthropogenetische Geomorphologie - Geomorophologie im Anthropoz{\"a}n : Virtuelle Jahrestagung des Arbeitskreises f{\"u}r Geomorphologie 2020, 28./29. September 2020, BTU Cottbus - Senftenberg}, address = {Cottbus}, issn = {2196-4122}, doi = {10.26127/BTUOpen-5363}, pages = {29}, language = {en} } @misc{VerschoofvanderVaartBonhageSchneideretal., author = {Verschoof-van der Vaart, Wouter and Bonhage, Alexander and Schneider, Anna and Ouimet, William and Raab, Thomas}, title = {Automated large-scale mapping and analysis of relict charcoal hearths in Connecticut (USA) using a Deep Learning YOLOv4 framework}, series = {Archaeological Prospection}, volume = {30}, journal = {Archaeological Prospection}, number = {3}, issn = {1099-0763}, doi = {10.1002/arp.1889}, pages = {251 -- 266}, language = {en} } @misc{BonhageRaabSchneideretal., author = {Bonhage, Alexander and Raab, Thomas and Schneider, Anna and Raab, Alexandra and Ouimet, William and V{\"o}lkel, J{\"o}rg and Ramezany, Shaghayegh}, title = {From site to state - Quantifying multi-scale legacy effects of historic landforms from charcoal production on soils in Connecticut, USA}, series = {Catena}, volume = {232}, journal = {Catena}, issn = {0341-8162}, doi = {10.1016/j.catena.2023.107426}, language = {en} }