@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{SchneiderBonhageRaabetal., author = {Schneider, Anna and Bonhage, Alexander and Raab, Alexandra and Raab, Thomas}, title = {Spatial and temporal variability of soil moisture in land-use legacy forest soils in Brandenburg, Germany}, 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-egu22-2182}, abstract = {Soil physical properties can show high heterogeneity in forest soils, implying a high spatial variability of soil moisture and plant water availability. Legacy effects of past land use, resulting in a small-scale mosaic of anthropogenically modified and unmodified soils in forest areas, further increase this spatial heterogeneity. The soils associated with relict charcoal hearths (RCH), most prominently characterized by a technogenic layer rich in charcoal fragments, are a widespread example for such land use legacy soils in forest areas. The objective of our study was to characterize the soil moisture regime of forest soils and RCH soils on sandy substrates in the northeastern German lowlands; and in particular to assess the long-term effect of the prolonged summer drought period in 2018 on spatial and temporal variability of soil moisture. We monitored matric potentials, soil water contents and soil temperature from June 2018 in forest soils in the Tauersche Forst (Brandenburg, Germany). Three soil profiles (one reference forest soil profile and two characteristic RCH soil profiles) were instrumented, sampled for laboratory analyses of bulk density, pore size distribution, saturated hydraulic conductivity, and persistence of water repellency; and root density distribution in the profiles was recorded. The soils in all profiles show low porosity and plant available water contents. On RCH soils, overall porosity is clearly higher compared with the reference soils, mainly related to larger volumes of coarse and fine pores. Soil moisture monitoring shows very high spatial and temporal variability of the recorded data after the prolonged dry period in 2018, with gradual rewetting over the winter periods and only short-term fluctuations of soil moisture in reaction to high-intensity precipitation events in the summer periods. The comparison of in-situ and laboratory-based water retention data shows strong hysteresis effects during the rewetting, with increasingly clear reactions of soil water contents to precipitation events over the years following the dry period, especially in the charcoal-rich substrates. The differences in soil moisture between the dry and the wetter periods were clearly higher in the RCH soils, which, compared with the reference soils, showed higher water contents under wet conditions and lower water contents under dry conditions. The results affirm that land use legacies can clearly increase the spatial and temporal variations of soil moisture in forest areas.}, language = {en} } @incollection{RaabHirschSchneideretal., author = {Raab, Thomas and Hirsch, Florian and Schneider, Anna and Raab, Alexandra}, title = {Geo{\"o}kologische Folgen historischer Landnutzung}, series = {Geoarch{\"a}ologie}, booktitle = {Geoarch{\"a}ologie}, editor = {Stolz, Christian and Miller, Christopher E.}, publisher = {Springer Spektrum}, address = {Berlin, Heidelberg}, doi = {10.1007/978-3-662-62774-7_8}, pages = {71 -- 77}, abstract = {Seit dem Neolithikum wirkt sich die Nutzung der Landschaft auf unterschiedliche Weise auf Relief, B{\"o}den, Gew{\"a}sser, Flora, Fauna und Klima aus. Insbesondere die Folgen land- und forstwirtschaftlicher Wirtschaftsweisen waren daf{\"u}r ausschlaggebend. Grunds{\"a}tzlich reagieren {\"O}kosysteme auf anthropogene Eingriffe, wie die Umwandlung von Wald in andere Nutzungsformen, mit einer schrittweisen Degradation sowie reversiblen oder irreversiblen Ver{\"a}nderungen. Beispiele sind Bodenerosion und eine ver{\"a}nderte Artenzusammensetzung. Die Absch{\"a}tzung des Ausmaßes im globalen Maßstab gestaltet sich generell schwierig. F{\"u}r die Geoarch{\"a}ologie bedeutsam sind daher haupts{\"a}chlich lokale Spuren fr{\"u}herer Bewirtschaftung und Formen im Kleinrelief, die sich im Gel{\"a}nde wiederfinden lassen und als Geoarchive fungieren. Denn sie geben Aufschluss {\"u}ber (pr{\"a}-)historische Bewirtschaftungsformen. So zeugen W{\"o}lb{\"a}cker, Hochbeete, Plaggenesche und die Relikte der historischen Teichwirtschaft, Moorkultivierung und K{\"o}hlerei von fr{\"u}heren Formen der Land- und Forstwirtschaft.}, language = {de} } @misc{BurasHirschSchneideretal., author = {Buras, Allan and Hirsch, Florian and Schneider, Anna and Scharnweber, Tobias and Maaten, Ernst van der and Cruz-Garc{\´i}a, Roberto and Raab, Thomas and Wilmking, Martin}, title = {Reduced above-ground growth and wood density but increased wood chemical concentrations of Scots pine on relict charcoal hearths}, series = {Science of The Total Environment}, volume = {717}, journal = {Science of The Total Environment}, issn = {1879-1026}, doi = {10.1016/j.scitotenv.2020.137189}, abstract = {Deciphering the drivers of tree growth is a central aim of dendroecology. In this context, soil conditions may play a crucial role, since they determine the availability of water and nutrients for trees. Yet, effects of systematically differing soil conditions on tree growth render a marginally studied topic. In this context, relict charcoal hearths (RCH) - a widespread legacy of anthropogenic charcoal production - render a valuable 'natural' experiment to study possible effects of artificially altered soil conditions on tree growth. We hypothesize, that the differing physico-chemical properties of RCH result in differing wood properties if compared to trees growing on unmodified soils. To test this hypothesis, we analyzed tree-growth, wood density, and wood elemental concentrations of Scots pine as well as physico-chemical soil properties. We applied a classic control-treatment design to compare RCH with unmodified soils. Our analyses identified significantly lower above-ground wood production but systematically higher wood elemental concentrations in RCH-trees compared to control trees. Since we could not identify treatment-specific growth patterns, we hypothesize the observed lower above-ground productivity of Scots pine to indicate an increased root-shoot ratio to compensate for a potentially lower plant water availability on RCH-sites. The observed higher wood elemental concentrations likely reflect higher soil elemental concentrations of Fe, Ca, K, and Mn in RCH soils. In conclusion, our study highlights diverse effects of RCH on tree growth and wood properties and strengthens the value of dendro-chemistry to use the tree-ring archive as proxy for soil conditions within a dendro-ecological context.}, language = {en} } @misc{RaabRaabBonhageetal., author = {Raab, Thomas and Raab, Alexandra and Bonhage, Alexander and Schneider, Anna and Hirsch, Florian and Birkhofer, Klaus and Drohan, Patrick J. and Wilmking, Martin and Kreyling, J{\"u}rgen and Malik, Ireneusz and Wistuba, Małgorzata and Maaten, Ernst van der and Maaten-Theunissen, Marieke van der and Urich, Tim}, title = {Do small landforms have large effects? A review on the legacies of pre-industrial charcoal burning}, series = {Geomorphology}, volume = {413}, journal = {Geomorphology}, issn = {0169-555X}, doi = {10.1016/j.geomorph.2022.108332}, pages = {16}, abstract = {Relict charcoal hearths (RCHs) are small, anthropogenic landforms resulting from past charcoal burning and reaching significant land coverage in pre-industrial mining areas. We review three coupled legacies linked by RCH development: (i) a landscape-scale geomorphic effect, (ii) a unique soil fingerprint, and (iii) an evolving novel ecosystem. The history and technique of charcoal production are described to clarify legacy effects. Applying a recently presented morpho-genetic catalogue is useful for classified mapping of RCH findings. The RCH numbers and calculated RCH densities per study region vary greatly and impose uncertainties due to insufficient methods causing over- or underestimations. Areas with high RCH densities between 50 and 500 RCH/km2 seem reasonable. Machine learning-based remote sensing techniques are promising approaches with which to better assess the full scale of charcoal burning legacies. RCH soil properties feature dark charcoal-rich technogenic substrate layers classified as Auh horizons according to the World Reference Base with significantly increased C contents. These Auh horizons can also exhibit specific physical and chemical properties, such as relatively low bulk density, high porosity, high plant available water content, low thermal conductivity and differences in cation exchange capacity or nutrient status. However, relevant studies are rare, and thus, the effects may differ by study region. Regarding vegetation, there seem to be four main effects: changes in forest structure, species composition, recruitment pattern and productivity. The number of studies on this issue is, however, also very limited. Even fewer studies have examined the soil fauna in RCHs; thus, the reported effects cannot be used to draw general conclusions. Notably, RCH research has made considerable progress in the last five years, especially in the Light Detection and Ranging-based mapping of these small landforms and identification of RCH-specific soil properties, but ecological legacies are not well understood; thus, more interdisciplinary and integrative studies are needed.}, 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} } @misc{SchneiderRaabRaabetal., author = {Schneider, Anna and Raab, Thomas and Raab, Alexandra and Sekhri, Simran and Bonhage, Alexander}, title = {Spatial distribution patterns and soil properties of former field systems in Northeastern Bavaria, Germany}, series = {Jahrestagung der Deutschen Bodenkundlichen Gesellschaft, Einladung und Programm Halle (Saale), 2.-8. September 2023}, journal = {Jahrestagung der Deutschen Bodenkundlichen Gesellschaft, Einladung und Programm Halle (Saale), 2.-8. September 2023}, pages = {88}, abstract = {Former field systems (FFS) in sloped forest areas are often discernible by a characteristic morphology with flattened slope areas and intermediary ridges formed by tillage erosion and colluvial redeposition. Soils of such lynchet field systems feature modified stratigraphy and properties and constitute a memory of past land use. At the same time, the legacies of past agriculture affect recent forest ecosystems. High-resolution digital elevation models (DEMs) allow to identify lynchets over large areas and open up new opportunities to study the FFS. Within our research on different land use legacy features in forest areas, we study FFS in Northeastern Bavaria (Germany) in a geopedological approach, combining large-scale mapping and spatial analysis with the description and analysis of soil properties for specific sites. Lynchet systems (and other remnants of pre-industrial FFS) in recent forests were mapped from LIDAR DEMs for an area of 2045 km2 (972 km2 forest area). The results show more than 100 km2 of FFS, mostly appearing as lynchet systems. Their spatial distribution patterns differ within the study area, mainly depending on parent material and landform. Soil stratigraphy and properties were studied for FFS and reference positions in six study sites, combining a characterization of principal soil profiles and an assessment of spatial soil property variations. The FFS soils are characterized by truncated profiles over most parts of the flattened slope areas and accumulation of colluvium upslope of lynchet risers. The depth of soil profile truncation and height of lynchet risers differ, mainly related to slope and erodibility of the initial soils. Stratigraphy of the lynchet soils indicates a gradually proceeding formation by tillage erosion. First results of soil property analyses show that carbon and nitrogen contents differ between FFS and reference soils and are more homogeneous within the FFS. Furthermore, physical properties of the FFS soils (bulk density, pore size distribution, hydraulic conductivity) are modified compared to unaffected forest soils through profile truncation and accumulation of colluvium. Overall, the results show that the legacy effects of past agriculture affect large fractions of recent forest areas, and can be of different quality depending on lithology of the soils' parent material and land use history.}, language = {en} } @misc{RaabDrohanRaabetal., author = {Raab, Thomas and Drohan, Patrick J. and Raab, Alexandra and Schneider, Anna and Bonhage, Alexander}, title = {A novel view in geopedology : how small landforms from past land use affect the pedosphere}, series = {Centennial Celebration and Congress of the International Union of Soil Sciences}, journal = {Centennial Celebration and Congress of the International Union of Soil Sciences}, publisher = {Florenz}, pages = {1}, abstract = {LiDAR-based high-resolution digital elevation models (DEMs) can now provide a centimetre-accurate image of the Earth's surface. Soil science is still in the early stages of realising how fundamentally this new technology will change our understanding of the formation, properties and functions of the pedosphere and in particular the uppermost part of it, which usually represents A horizons. With the help of high-resolution DEMs, it is possible to identify and classify small topographic features that were previously not considered in soil mapping. Therefore, precise landform analyses will be crucial in assessing variations in soil horizonation and soil stratigraphy and will provide the framework for a new perspective in Geopedology that truly integrates Geomorphology and Pedology from pedon to soil landscapes. In the digital domain, this geopedological approach is growing rapidly by using artificial intelligence (AI) to automatically identify small landforms and visualise the heterogeneity of diverse pedological information. We present the results of the study of different types of relict anthropogenic landforms (RALs) and highlight their characteristics and differences compared to natural, undisturbed soils. The origins of these relict features can vary greatly, as can their distribution, morphology and age. The analysis of high-resolution relief models in Europe and the USA shows that morphological features can be found, particularly in forest that were created in pre-industrial times. Settlement structures (e.g. stone walls, burial sites) or linear relief forms created by soil cultivation (e.g. field terraces, furrow systems) are common. Relict Charcoal Hearths (RCHs), which originate from historic charcoal burning, are usually small circular platforms surrounded by pits or ditches, but can still cover a considerable part of the area. A relatively complex geomorphology can be observed in historic mining areas, which may include different landform types such as mine shafts and spoil heaps, resulting in a very heterogeneous pedological mosaic. To summarise, all studies reveal a high variation of soil properties controlled by small relief structures. Pedology should take this more into account in the future and improve knowledge of the impact of RALs on the pedosphere and other components of ecosystems.}, language = {en} } @misc{SchneiderRaabRaabetal., author = {Schneider, Anna and Raab, Thomas and Raab, Alexandra and Bonhage, Alexander}, title = {Legacies of past land use : mapping anthropogenic landforms in forest areas of eastern Bavaria, Germany}, series = {Geoarchaeology}, volume = {40 (2025)}, journal = {Geoarchaeology}, number = {1}, publisher = {Wiley}, issn = {0883-6353}, doi = {10.1002/gea.22032}, pages = {1 -- 18}, abstract = {Reconstructing (pre-)historic land use distribution is essential for understanding past human societies and their impacts on the environment. Various land use forms result in distinct alterations of surface morphology, which are often well preserved but rarely described within forest areas. The interpretation of LiDAR Digital Elevation Models (DEMs) can greatly enhance our insight into the geoarchaeological records of woodlands. This study examines the legacies of past land use in forested areas of Upper Palatinate, Germany, utilizing LiDAR DEMs to map anthropogenic relief features. We comprehensively mapped land use legacy landforms (LULLs) that occur with considerable frequency in the study area, that is, former agricultural field systems, road remnants, abandoned ponds, relict charcoal hearths, mining legacies, and indicators of anthropogenically induced soil erosion. Results reveal that 17\% of the forested area is affected by LULLs, with the largest areas covered by former field systems, roads, and ponds. Characteristic LULL associations reflect past agricultural and charcoal production landscapes. While erosion indicators often coincide with field systems and roads, natural factors mainly influence their distribution. Comparison with historical maps suggests pre-19th-century abandonment of most LULLs and good preservation of anthropogenic relief modifications. Our results underscore the enduring impact of past land use on present woodland ecosystems and emphasize the importance of considering forest areas in the analysis of past human-landscape interactions.}, language = {en} } @misc{SchneiderRaabRaabetal., author = {Schneider, Anna and Raab, Thomas and Raab, Alexandra and Bonhage, Alexander}, title = {Anthropogene Kleinreliefformen als Relikte fr{\"u}herer Landnutzung - Großfl{\"a}chige Kartierung aus digitalen Gel{\"a}ndemodellen}, series = {Pangeo / DEUQUA 2024 Abstracts}, journal = {Pangeo / DEUQUA 2024 Abstracts}, pages = {159 -- 159}, abstract = {Die direkten Auswirkungen menschlicher Landnutzung auf B{\"o}den und Sedimente betreffen h{\"a}ufig nur wenige Dezimeter Tiefe unter der Erdoberfl{\"a}che, erstrecken sich horizontal aber sehr weitr{\"a}umig. Indirekte anthropogene Einfl{\"u}sse auf geomorphologische und hydrologische Prozesse als ein Merkmal des Anthropoz{\"a}ns ergeben sich als kumulative Auswirkungen solcher wenig intensiven, aber großfl{\"a}chigen Eingriffe. Viele Landnutzungsformen hinterlassen charakteristische anthropogene Reliefver{\"a}nderungen und Kleinreliefformen, die in hochaufl{\"o}senden digitalen Gel{\"a}ndemodellen (DEMs) abgebildet sind. Die Auswertung von DEMs erm{\"o}glicht es damit, anthropogene Kleinreliefformen {\"u}ber große Areale zu erkennen und so (pr{\"a}-)historische Landnutzung zu lokalisieren und hinsichtlich ihrer fl{\"a}chenhaften Verbreitung und Verteilungsmuster zu beschreiben. W{\"a}hrend sich die technischen M{\"o}glichkeiten zur DEM-Auswertung v.a. durch KI-gest{\"u}tzte Methoden rapide weiterentwickeln, bleiben vielfach Unsicherheiten hinsichtlich der zeitlichen Klassifizierung und Repr{\"a}sentativit{\"a}t der erfassten Formen. Wir pr{\"a}sentieren Ergebnisse aus mehreren Fallstudien, in denen anthropogene Kleinreliefformen aus DEMs großfl{\"a}chig kartiert und erg{\"a}nzt durch bodenkundliche und sedimentologische Untersuchung morphogenetisch interpretiert wurden. Diese Studien konzentrieren sich auf Relikte der Holzkohleproduktion, des Bergbaus und der landwirtschaftlichen Nutzung in Untersuchungsgebieten in Brandenburg, Nordbayern, Schlesien, Nordwestirland und dem Nordosten der USA. Unsere Ergebnisse zeigen durchwegs eine große Verbreitung anthropogener Kleinreliefformen in rezenten Waldgebieten und damit einen erheblichen Einfluss fr{\"u}herer Landnutzung auf aktuelle Bodenlandschaften. W{\"a}hrend Relikte der historischen Holzkohleproduktion nur vereinzelt mit Bodenerosion in Verbindung stehen, zeigt sich f{\"u}r Kleinreliefformen aus Bergbau und Ackerbau h{\"a}ufiger ein Zusammenhang mit anthropogen beeinflusster Morphodynamik. Die Fallstudien zeigen auch Effekte der {\"U}berpr{\"a}gung und eine Tendenz zur Abbildung {\"u}berwiegend j{\"u}ngerer Landnutzungsrelikte in DEMs und unterstreichen damit, dass f{\"u}r ein Verst{\"a}ndnis von Mensch-Umwelt Interaktionen die DEM-gest{\"u}tzte Rekonstruktion der vergangenen Landnutzung mit Auswertung weiterer Geoarchive kombiniert werden muss.}, language = {de} }