Eastern Sudetes Research Articles

THE ROLE OF OPEN-AIR CALVARIES IN THE CONTEXT OF LANDSCAPE HERITAGE PROTECTION OF THE EASTERN SUDETES

The article concerns the meaning and landscape functions of Small Calvaries located in the Eastern Sudetes in the border area of the Czech Republic and Poland. The publication aims to indicate the main typological features of this type of calvary, taking into account the current behaviour of residents having a common sarcastic heritage. Due to the subject, interdisciplinary research was undertaken in the direction of valorization as well as environmental interviews. The use of geosociological methodology made it possible to assess the landscape in terms of its contemporary functions and potential threats. The research allowed us to distinguish two types of landscape layouts: elliptical and linear of a historical nature, and modern, mainly linear. Sociological research showed the attitude of local communities to the sacred heritage in the Eastern Sudetes.

Evolution of Weichselian aeolian strata on a coarse-grained substrate in a rugged piedmont topography: A case study from the foothills of the eastern Sudetes Mts., Czechia

The southern margins of the northern European loess belt on the foothills of Eastern Sudetes Mountains are less explored sedimentation zones. This study provides new data about the development of aeolian silty-sandy sediments overlying the glaciofluvial succession on the rugged topography near the village of Kolnovice. The Kolnovice sand quarry (360 × 200 m), which lies at the margin of the upland plateau, is the only active-mined outcrop on the foothills of the Eastern Sudetes and is large enough to study Pleistocene (peri-)glacial sediments. To examine the origin of these sediments, we applied lithofacies analysis (both macro-description of outcrop walls and micromorphological study of thin sections) and surface analysis of quartz grains. Periglacial structures have been identified within the sediments, allowing us to further interpret the post-sedimentary evolution of the sedimentary succession. The studied sediments resulted from colluvial redeposition of aeolian sediments, which was controlled particularly by the topography, glaciofluvial substrate, and climatic conditions. The underlying glaciofluvial sediments are the most crucial source of the studied sediments, although the fine-grained material could have been transported from more distant areas.

Fate and preservation of the late pleistocene cave bears from Niedźwiedzia Cave in Poland, through taphonomy, pathology, and geochemistry

This comprehensive study examines fossil remains from Niedźwiedzia Cave in the Eastern Sudetes, offering detailed insights into the palaeobiology and adversities encountered by the Pleistocene cave bear Ursus spelaeus ingressus. Emphasising habitual cave use for hibernation and a primarily herbivorous diet, the findings attribute mortality to resource scarcity during hibernation and habitat fragmentation amid climate shifts. Taphonomic analysis indicates that the cave was extensively used by successive generations of bears, virtually unexposed to the impact of predators. The study also reveals that alkaline conditions developed in the cave during the post-depositional taphonomic processes. Mortality patterns, notably among juveniles, imply dwindling resources, indicative of environmental instability. Skeletal examination reveals a high incidence of forelimb fractures, indicating risks during activities like digging or confrontations. Palaeopathological evidence unveils vulnerabilities to tuberculosis, abscesses, rickets, and injuries, elucidating mobility challenges. The cave’s silts exhibit a high zinc concentration, potentially derived from successive bear generations consuming zinc-rich plants. This study illuminates the lives of late cave bears, elucidating unique environmental hurdles faced near their species’ end.

The current state of relic rocky grasslands with <i>Sesleria tatrae</i> and <i>Calamagrostis varia</i> in the Eastern Sudetes (Śnieżnik Massif, SW Poland)

The unique, basophilic rocky grasslands on the Pulinka rock near Kletno in the Śnieżnik Massif (Eastern Sudetes) have been known since the 1960s. The aim of the study was to, re-analyze the status of this plant community with reference to species composition, functional structure, habitat conditions and syntaxonomic position 50 years afer its discovery, and first description. For this purpose, we used archival and contemporary data. The obtained results revealed close compositional similarity between the vegetation plots collected in 1968 and 2022. The abundance of relic species documented in phytosociological relevès has remained constant (<i>Sesleria tatrae</i>, <i>Galium anisophyllon</i>) or increased (<i>Scabiosa lucida</i>). Additionally, the first locality of <i>Calamagrostis varia</i> was found on the Pulinka – a species not yet recorded in the Sudetes. On the other hand, some regular fluctuations in the abundance of sporadic species were observed. However, these were not reflected in changes in community-weighted means for environmental variables (temperature, light, nutrients, soil reaction, and moisture) and functional traits (specific leaf area, seed mass, and leaf dry matter content). We also found no differences in the functional diversity index (FD Rao) between the first and last surveys. Therefore, the lack of temporal changes in the main ecological features may indicate a high stability of the studied grasslands despite the pressure of external factors (progressive climate warming and nitrogen deposition). The phytosociological analysis carried out suggests that the studied community belongs to the class <i>Elyno-Seslerietea</i> and the order <i>Seslerietalia caeruleae</i>. However, due to the unusually poor species composition of the studied rocky grasslands, we did not find it currently possible to classify them at the alliance and association level. This requires further studies and classification based on broader data, including Western Carpathian calcicolous swards.

Mid-Miocene onset of the NE Bohemian Massif (SW Poland, Europe) growth, landscape evolution, and paleoenvironmental changes unraveled using paleokarst sediment palynology

Newly discovered paleokarst sediments with an abundant Miocene palynological record in the Eastern Sudetes bridge the gap in reconstructing the landscape and tectonic history of the NE Bohemian Massif during the Neogene. Palynological analysis performed for seven samples derived from the karst fissure allowed the examination of the sporomorph distribution (pollen grains and spores of plants) and nonpollen palynomorph content (algal and fungal microremains) in each layer. The results revealed the presence of numerous pre-Quaternary taxa, including “paleotropical” species, within the analyzed sediments. The pollen analysis results indicate a warm-temperate and humid climate during sedimentation of the Nowy Waliszów karst infill, along with the development of wetland vegetation (swamp forests, riparian forests, and shrub bogs) and mesophytic forests. Recorded taxa are typical for flat and hilly landscapes, predating growth of the present >1000-m relief mountainous topography and formation of the primary European triple drainage divide in the Śnieżnik Massif area. Paleokarst palynology strongly supports a mid-Miocene (∼15 ± 1.5 Ma) onset of environmental change in the Sudetes due to accelerated tectonic uplift of the Eastern Boundary Fault bounding the Upper Nysa Kłodzka Graben and Orlica–Śnieżnik Dome tectonic block. The data presented enhance our understanding of the pre-Pleistocene development of the NE Bohemian Massif, with a particular focus on the orogen-scale landscape evolution from flat, inland wetlands to hilly, mountainous topography.

Natural radioactivity in select metamorphic and sedimentary rocks of the Opava Mountains (Poland): A comparison between laboratory and in situ measurements of 232Th, 238U, and 40K activities

rocks from the Opava Mountains region (Eastern Sudetes, Poland) as measured in the laboratory and under in situ field conditions. Activity concentrations for 232Th, 238U, and 40K were obtained using an HPGe gamma-ray spectrometry system. Activities for 232Th ranged from 2 to 39 Bq kg−1 as measured in the laboratory and from 5 to 38 Bq kg−1 measured under in situ field conditions. For 238U, the activity concentrations ranged from 4 to 37 Bq kg−1 in the laboratory and from 7 to 42 Bq kg−1 under in situ field conditions. For 40K, activity concentrations ranged from 12 to 820 Bq kg−1 in the laboratory and from 60 to 826 Bq kg−1 under in situ field conditions. Measured activity concentrations were compared with average activity concentrations of radionuclides in similar types of rocks from different global localities. The in situ field measurement and laboratory measurements did not show significant differences indicating that both methods provide reliable 232Th, 238U, and 40K results for different lithologies.

Subalpine vegetation changes in the Eastern Sudetes (1973–2021): Effects of abandonment, conservation management and avalanches

AbstractAimsThe summit grasslands of many European mountain ranges were historically used for summer grazing, which ceased in the 20th century. These grasslands are changing, partly through succession after abandonment and partly owing to environmental changes. Subalpine vegetation is also affected by artificially reduced avalanche frequency. Recent conservation efforts have attempted to reverse the negative trends of change. We ask: (1) How has subalpine vegetation changed following the abandonment and avalanche control? (2) Was conservation management able to reverse the post‐abandonment trend of vegetation change? (3) Did avalanche disturbance have a positive effect on plant species diversity?LocationSummit area of the Hrubý Jeseník Mountains (1,491 m a.s.l.), Eastern Sudetes, Czech Republic.MethodsVegetation plots sampled in the 1970s were resurveyed in the 2000s and again in 2021. Subalpine vegetation was classified into six types, and transitions between these types over time were quantified. Vascular plant species richness and the proportion of threatened species were compared between periods, between areas with and without conservation management, and between areas affected vs unaffected by a large avalanche from 2019. Species composition was analysed using principal coordinate analysis and distance‐based redundancy analysis.ResultsVegetation types remained relatively stable except for species‐rich grasslands, some of which changed to heathlands or tall‐forb vegetation. Some competitive species have increased, and species specialized to threatened habitats declined. Conservation management systematically implemented after 2010 slowed the decline of habitat‐specialized species but did not reverse it. Disturbance by an avalanche positively affected species richness but not the number of threatened species.ConclusionsSubalpine vegetation is slowly losing its plant diversity owing to grazing cessation and possibly acidification from past atmospheric deposition. Recently implemented conservation management and restoration of avalanche activity are essential to stop this trend, but future monitoring is needed to evaluate the success of management actions.

Norway spruce phenotype variability determined by needle anatomy in Bohemian Forest compared to other regions of the Czech Republic

Young trees (saplings) of the Norway spruce (Picea abies [L.] Karst.) regenerating populations were analysed on 7 plots in the Šumava Mts. (Bohemian Forest), on 5 plots in the Jeseníky Mts. (Eastern Sudetes), and 1 plot in the Krkonoše (Giant Mts.). All 13 plots were located at the forest altitudinal (vegetation) zones of natural Picea abies stands. Each selected tree was characterized by microscopic features of the first-year needles. The free-hand needle cross-sections were prepared from three needles of each tree and measured by digital microphotos. The following needle characteristics were measured: width, thickness, and vascular bundle diameter. Each population was described by variability of these parameters. Populations were classified based on the data set. Two artificially planted populations were most different. Populations resulting in natural stands have different phenotype variability, possibly as a result of the parent stand history: two extreme examples are Eustaška locality (Jeseníky Mts.) with no known disturbance, and Trojmezí locality (Šumava Mts.), where wind and bark beetle disturbances were repeatedly recorded.

Litter leachate as a potential selector of woody species germination at alpine treeline

ABSTRACT The advancement of upper forest limits is driven by environmental conditions, but our current understanding overlooks the attributes of habitats and germination ability of woody species. Habitats, through plant litter, impact the competitive relation of germination and seedling growth. The aims of this study were to identify the selective effect of six litter leachates on the germination of indigenous Norway spruce (Picea abies) and nonindigenous dwarf pine (Pinus mugo) and compare the germination rates of the species. We collected plant litter and seeds from the (sub)alpine belt of the Hrubý Jeseník Mts. (the Eastern Sudetes Mts.; the Czech Republic). We evaluated the effect of plant litter leachates from alpine heathlands, wind-swept alpine grasslands, subalpine tall-herb plants, Pinus mugo scrub, subalpine Vaccinium vegetation, and Norway spruce clonal groups on germination process under standard light and temperature conditions. The germination of Norway spruce was inhibited by the litter leachate from subalpine tall-herb vegetation mainly dominated by Calamagrostis villosa, whereas that of dwarf pine was not. The other five litter leachates had no significant effect on the both. Under standard conditions, the germination time of dwarf pine is on average one day faster. These results suggest that most of the litter leachates examined may have small impacts on the germinability and germination time of Norway spruce and dwarf pine, but litter from the subalpine tall-herb vegetation can act as a filter that influences the seedling composition of the woody species.

Thermal basal regime of the Elsterian ice‐sheet marginal zone in a hilly mountain foreland, Rychleby Mts., Eastern Sudetes

The Scandinavian Ice Sheet reached the Sudetes and Carpathian Mountains during the Elsterian glaciation. A long ice‐sheet piedmont marginal zone affected by the rugged mountain foreland topography and associated slopes originated. This study focuses on the hilly Rychleby Mts. foreland (Eastern Sudetes, Czechia), which was a part of the piedmont marginal foreland zone of the ice sheet. The basal regime was reconstructed through an investigation of the sedimentology, structural features, and the nature of ice‐sheet erosion of preglacial landscapes evident at two sites located ~3–5 km inside the maximum ice‐sheet extent. These sites show a preglacial relief buried by sub‐ to supraglacial sediments. The sites were located under an ice cover of max. 200 m. Evidence of cold‐based conditions (including palaeotors with delicate structures on the bedrock, almost absent striations on clasts, originally frozen unlithified sedimentary rafts) exists at both sites. Permafrost composed of coarse‐grained sediments was subject to brittle deformation at the base of the ice sheet, whereas permafrost composed of fine‐grained sediments underwent ductile deformation. The margin of the Scandinavian Ice Sheet in the Rychleby Mts. foreland was cold‐based, therefore glacial erosion was not sufficient to significantly remodel the palaeotors into roches moutonnées. During ice‐sheet decay, the preglacial landscape was partially buried by melt‐out tills and meltwater sediments.

Tourmalines as a Tool in Provenance Studies of Terrigenous Material in Extra-Carpathian Albian (Uppermost Lower Cretaceous) Sands of Miechów Synclinorium, Southern Poland

The mature transgressive Albian quartz sands in the Miechów Synclinorium contain a poor (<1%) heavy mineral suite consisting of tourmaline, rutile, garnet, staurolite, ilmenite, zircon, monazite, kyanite, and gahnite. The other minerals, especially those containing Fe and Ti (e.g., biotite), are subordinate. Over 512 tourmaline grains from seven outcrops in the Miechów Segment were analysed using electron probe microanalysis (EPMA). The majority of grains belong to the alkali tourmaline group in which the X-site is dominated by Na (0.4 to 0.9 apfu). Detrital tourmalines are mainly dravite with a prevalent schorl end-member with average XMg values over 0.6. Apart from Mg and Fe, the other Y-site cations rarely exceed 0.1 apfu. Fluorine content is usually below the detection limit. Their chemical composition suggests that most tourmaline grains were sourced from Al-rich and Al-poor metapelites/metapsammites. The main source rocks for the Albian sands were rocks from low- to medium-grade metamorphism, probably from Al-rich quartz-muscovite schist and/or muscovite rich gneisses. Additional minor source rocks were granites and pegmatites coexisting with them. A comparison of the examined tourmaline to tourmaline from possible source areas indicates that these areas were located in the eastern part of the Bohemian Massif and/or eastern Sudetes.

Ancylite-(Ce) from quartz-calcite-chlorite veins in phyllite of the Opava Mountains (SW Poland)

Ancylite-(Ce) occurs in quartz-calcite-chlorite veins crosscutting the foliation of phyllite in the Dewon Quarry in the foothills of the Opava Mountains of the eastern Sudetes, south-west Poland. Irregularly shaped grains of ancylite are up to 67 mm long and 22 mm wide. The compositional range of ancylite, determined by electron microprobe, is expressed by the empirical formula: (Sr 0.65-0.55 Ca 0.19-0.14 Fe 0.03-0.00 ) Σ0.87-0.69 (Ce 0.58-0.50 Nd 0.26-0,22 La 0.26-0.21 Pr 0.06-0.05 Sm 0.05-0.04 Gd 0.07-0.03 Dy 0.01-0.00 ) Σ1.29-1.05 (CO 3 ) 2 (OH 1.07-0.99 F 0.22-0.0.06 ) 1.29-1.05 . 0.95-0.93H 2 O. Ancylite crystallized directly from CO2-rich hydrothermal solutions as the last mineral in the veins following precipitation of calcite. The solution temperature, estimated using various chlorite geothermometres, was in the range of 260–340°C.

Factors Affecting the Health Condition of Spruce Forests in Central European Mountains-Study Based on Multitemporal RapidEye Satellite Images

Spruce stands in the mountains of Central Europe are particularly valuable, not only because of their natural and scenic values but also because of their role in the protection of watersheds and soil. Over the past decades, these stands were frequently exposed to massive deforestation caused by various biotic, abiotic and anthropogenic factors. The current health condition of spruce stands in the Eastern Sudetes shows that the next phase of deterioration of these stands has begun. Bearing in mind past experiences and the current situation in these mountain areas, it is particularly important to understand the processes and factors that may short-term (2012–2016) spruce health analyses based on the normalized difference red-edge index and RapidEye satellite imagery, which is being delivered annually. Aided by remote sensing data and Boosted Regression Trees, it was possible to determine the topographic and tree stand features having the greatest impact on the vitality of spruce in all analyzed areas during 2012–2016. As the results show, the highest impact on the value of the normalized difference red-edge index indicator comes from a height above sea level, age of stands, terrain slopes, and exposure. In various areas, these factors may affect the vitality of spruce to varying degrees but not always in the same way. Our models accurately explained 74–81% of the randomly selected input data (predicted 72–80% of the excluded data) for site A, 50–58% for site B (48–57% for tested data) and 54–70% for site C (52–69% for excluded data).

Polykinematic foreland basins initiated during orthogonal convergence and terminated by orogen-oblique strike-slip faulting: An example from the northeastern Variscan belt

An extensive early Carboniferous foreland basin (the Moravosilesian Culm Basin, MSCB) delineates the northeastern margin of the Bohemian Massif (Variscan orogenic belt). The basin overlays a complex suture between the outer Brunovistulia microplate, forming a promontory previously accreted to Laurussia, and inner Gondwana-derived units that form the remainder of the Bohemian Massif. Our structural, paleomagnetic and magnetic anisotropy data from the eastern portion of the MSCB indicate that its depositional architecture, internal fabric, and deformation by folding and faulting record a major switch from orthogonal convergence to orogen-oblique strike-slip shearing. First, the Brunovistulia microcontinent was subducted frontally towards W during ~346–335 Ma, followed by a shift of the subduction vector towards ~SSW at around 335–330 Ma. From ~330 Ma onwards, the underthrusting had ceased and the ~WNW–ESE dextral Elbe shear zone, related to the westward movement of Gondwana with respect to Laurussia, controlled deformation of this region. Displacement of the northerly Eastern Sudetes ‘block’ towards ~ESE produced regional ~WNW–ESE pure-shear shortening against the Brunovistulia indentor and resulted in an overall doubly-vergent structure of the MSCB. Simultaneously, the southerly Moldanubian unit was translated towards ~WNW, away from the Brunovistulian microplate, and likely contributed to an extensional regime related to orogenic collapse progressing outward from the internal domains of the Bohemian Massif. On a larger scale, we suggest that the MSCB is an illustrative example of a polykinematic foreland basin, where deposition, syn- to post-sedimentary deformation, and thus geodynamic processes changed significantly during basin evolution, starting off with microplate impingement into a continental margin reentrant and terminated by strike-slip shearing. Our data also do not support previous models for the tectonic development of the northeastern termination of the Variscan Belt, which suggested either a large-magnitude, vertical-axis oroclinal rotation of the foreland or its translation along an orogen-perpendicular strike-slip fault.

Response of a mountain‐foreland fluvial system to an advancing ice sheet, southern Poland

In this paper, fluvial deposits of Middle Pleistocene age in the mountain‐foreland area of southern Poland (Eastern Sudetes and Western Carpathians) are studied in order to document the evolution of fluvial systems during the coldest stages of glacial periods when the Scandinavian Ice Sheet advanced far to the south. The focus is on fluvial response to climate change and glacial impact on river system behaviour. Also considered is the tectonic uplift of the mountain part of river catchments and its potential influence on the style of fluvial sedimentation in the fore‐mountain area. Three drainage basins that were active during the Elsterian and Saalian glaciations are investigated. Facies analyses are carried out on thick successions of braided river deposits covered with till or glaciolacustrine sediments, which result in a reconstruction of the fluvial activity synchronous with the ice‐sheet advance. The results suggest that fluvial activity declined prior to ice‐sheet advance into the fore‐mountain area. This climatically induced change is directly recorded in alluvial successions by upward‐decreasing bed thicknesses and grain sizes. River longitudinal profiles were shortened in front of the advancing ice sheet. The base level of the studied rivers, created by the ice‐sheet margin, rose in parallel with glacial advance. As a result, the successive reaches of rivers (degradational, transitional, aggradational) underwent shortening and moved upstream within the catchments. Moreover, tectonically induced local increases of river slopes may have influenced the depositional processes.

Reply to: Comment on ‘Geophysical approach to the study of a periglacial blockfield in a mountain area (Ztracené kameny, Eastern Sudetes, Czech Republic) by Stan et al. (2017). Geomorphology 293, 380‐390

The authors present the answer to the discussion paper presented by Uxa et al. (2018). The remarks provided will explain ambiguities regarding the use of geophysical methods used to detect ice in typically nonconducive environments that are potentially unfavourable to its occurrence, namely the quartzite block cover Ztracené kameny (1245 m asl). The authors discuss the most important remarks regarding ice formation and preservation. Discussion points focus on the following: (1) permafrost in low altitude blockfields and related environmental settings, (2) geophysical interpretation, (3) extreme quartz/quartzite resistivities hypotheses, and (4) additional comments.

Unravelling the recent dynamics of headwaters based on a combined dendrogeomorphic approach (a case study from the Sudetes Mts., Czech Republic)

ABSTRACTHeadwater catchments are frequently prone to debris flows/floods. Dendrogeomorphic methods allow for the accurate dating of the frequencies and spatial patterns of these events. Nevertheless, a combined approach based on the sampling of increment cores from tree stems and the extraction of cross-sections of scarred roots has been rarely used together at one site to determine the headwater dynamics. Such sampling strategy was performed in the Rudohorský potok catchment (the Hrubý Jeseník Mountains, Eastern Sudetes, Czech Republic) to compile the debris flow/flood chronology and to describe the detailed spatial patterns in the studied sub-catchments. In total, 44 events of increased hydrogeomorphic activity during the last 110 years were identified based on the analysis of 860 growth disturbances from 322 trees and 85 roots. The largest events (debris flows) occurred in 1921, 1951, 1965, 1975, 1991, 1997, 2001 and 2010. Higher dynamics of hydrogeomorphic processes were investigated in the sub-catchment affected by deep-seated rockslides. The inclusion of root analyses facilitated the completion of the event chronology mainly during the last 20 years. With respect to the decreasing sensitivity of tree stems with increasing age to the recording of geomorphic disturbances, the root analysis helped to better illustrate the spatial imprint of recent debris flow events (especially the most recent one in 2010).

Comment on ‘Geophysical approach to the study of a periglacial blockfield in a mountain area (Ztracené kameny, Eastern Sudetes, Czech Republic)’ by

Stan et al. (2017) investigated the internal structure of two periglacial blockfields on the Ztracené kameny site, Eastern High Sudetes, Czech Republic, using electrical resistivity tomography and seismic refraction tomography and interpreted two high-resistivity and high-velocity zones as remnants of the Pleistocene permafrost. However, we believe that in reality no permafrost occurs on the site, and we provide alternate, non-permafrost interpretations of the geophysical measurements by Stan et al. (2017) that are well consistent with other evidences such as climate and topographic attributes of the blockfields, permafrost-disqualifying ground thermal regimes, and common characteristics of mid-latitude, low-altitude permafrost locations from elsewhere. We also rectify some misconceptions about the study site that are stated by Stan et al. (2017).

Increased gully activity induced by short-term human interventions – Dendrogeomorphic research based on exposed tree roots

The recent acceleration of gully erosion caused by environmental factors and human impacts has led to an enhanced demand for applied research in risk-prone areas worldwide. We investigated the dynamics of gullies that have recently threatened dwellings and railways in the foreland of the Eastern Sudetes (340–390 m a.s.l. in the NE part of Czechia). Flood countermeasures in a residential area above the study site created conditions conducive to accelerated erosion in the gullies; thus, the main aim of this study was to determine how human interventions changed the spatio-temporal dynamics of the gullies during a short period. Twenty two gullies (with a mean length 48.5 m) have developed on a 1-km-wide escarpment (with a mean slope 25°) composed of glaciogenic sediments of various sizes. Dendrogeomorphic techniques were applied on 23 exposed roots of Tilia cordata Mill. (a tree species that has never been used to detect root exposure). Microsections were prepared using a G.S.L.1 sledge microtome and analysed using the WinCELL Reg software to determine the timing of root exposure.Approximately 90% of the eroded sediments (1287.4 m3) were transported across the railway onto the floodplain and caused damage to dwellings, while approximately 10% created bare accumulations at the gully floors. The most significant pulses of gully erosion occurred during the last 10 years (2007, 2009, 2010, and 2014). The maximum identified gully erosion occurred in 2014 (max. incision: 154 cm; maximum widening: 160 cm). In contrast, the development of the bank failures has been slowly progressing since the early 1990s, with a mean bank eroded area between 0.07 and 0.12 m2 year−1. The analysis of the precipitation characteristics (1963–2016) with the Mann-Kendal trend test revealed no significant trend. However, the last strong erosion event, in May of 2014, was triggered by an extraordinary rainstorm with an hourly intensity of 41.3 mm h−1 (maximum intensity of 2.8 mm min−1). Therefore, the recent increase in gully erosion is the consequence of extreme precipitation and human interventions that have been performed in the study site since 2007 (i.e., damming of the ditches and building of new culverts). The dendrogeomorphic research of exposed T. cordata roots significantly contributed to the identification of the gully erosion pulses and thus can be further applied in other localities.

Characteristics of large wood in a headwater channel after an extraordinary event: The roles of transport agents and check dams

High-magnitude hydrogeomorphic events in steep streams (e.g., debris flows and debris floods) are capable of transporting considerable quantities of bed material, including large wood, although wood pieces that are longer than the channel width are often perceived as relatively stable elements in narrow headwater channels. We investigated present large wood distribution along 1.7 km of a steep headwater channel (the Klepáčský Stream; Eastern Sudetes; NE Czech Republic) surrounded by managed forests and engineered by twelve check dams (presently at various stages of destruction). The total wood volume was measured at 123.0 m3, including wood deposited on adjacent terraces by a high-magnitude hydrogeomorphic event in 2010 representing a ca. 20–30 year recurrence interval. Approximately a half of the total wood volume (58%) was stored in large jams (≥10 large wood pieces) that originated during that event. We observed reach controls (based on transport agents and valley morphology) and local controls (represented by individual check dams) of LW depositional patterns. The uppermost debris flow-affected reach produced high volumes of mobilised wood, including many pieces that were two-to-three times longer than the local active channel width; significantly shorter and thinner pieces were found within large jams in downstream reaches void of debris-flow processes. We also documented that this high-magnitude event was responsible for the notable out-of-channel storage of large wood, which decreases the volume of wood that might be transported by a future event. In addition, 30.5 m3 of large wood, that is ~one-quarter of the total volume measured along the stream, was deposited in relation to twelve damaged check dams despite their lowered trapping efficiency.