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The northeastern United States experienced extensive deforestation during the seventeenth through twentieth centuries primarily for European agriculture, which peaked in the mid-nineteenth century,...

In the northeastern United States, widespread deforestation occurred during the 17–19th centuries as a result of Euro-American agricultural activity. In the late 19th and early 20th centuries, much of this agricultural landscape was reforested as the region experienced industrialization and farmland became abandoned. Many previous studies have addressed these landscape changes, but the primary method for estimating the amount and distribution of cleared and forested land during this time period has been using archival records. This study estimates areas of cleared and forested land using historical land use features extracted from airborne LiDAR data and compares these estimates to those from 19th century archival maps and agricultural census records for several towns in Massachusetts, a state in the northeastern United States. Results expand on previous studies in adjacent areas, and demonstrate that features representative of historical deforestation identified in LiDAR data can be reliably used as a proxy to estimate the spatial extents and area of cleared and forested land in Massachusetts and elsewhere in the northeastern United States. Results also demonstrate limitations to this methodology which can be mitigated through an understanding of the surficial geology of the region as well as sources of error in archival materials.

The effects of historical charcoal production on forest soil properties are increasingly well studied on sites in Europe and the northern USA. The most obvious effect of this past forest use practice is the addition of large quantities of charcoal into the soil at sites of former charcoal production. These so called relict charcoal hearth (RCH) sites are mapped in expansive numbers due to the rising availability of high-resolution LiDAR data. However, studies determining the impact of RCHs on more than a field plot scale are rare, so far. To transform results from specific RCH sites to a landscape scale, we sampled and measured 52 RCH sites on a 0.7 km² area in the Litchfield Hills in western Connecticut, USA.In this study we combine field based measurements of RCH site stratigraphy and geometry, GIS-based spatial analysis of site locations, laboratory determination of soil organic and pyrogenic carbon and FTIR-based analysis of soil carbon. We aim at assessing the soil distribution and soil development in an RCH affected landscape, i.e. the distribution of three typical soils commonly found in these landscapes: natural forest soils, technogenic soils of RCH platforms and soils buried below technogenic soils. Furthermore, we determine the distribution of organic and pyrogenic carbon in these soils and specifically the variation of carbon contents within the technogenic RCH soil stratigraphy.Preliminary results suggest that RCH site occurrence does not depend on relief position, i.e. RCH site abundance is not correlated with slopes, plateau or flatland positions. However, RCHs with multiple layers of technogenic substrates are more abundant on slope positions. RCH soils have a significantly increased content in total carbon compared to unaffected forest soils. Multi-layered RCHs have a heterogeneous vertical distribution of pyrogenic carbon and a possibly modern enrichment of organic matter in the surface soil. Wet chemical digestion of RCH soil samples coupled with FTIR analysis shows an increased presence of aromatic compounds and therefore pyrogenic carbon. However, the majority of carbon in RCH soils seems to be of non-pyrogenic origin. As of now it is unclear, whether the content of pyrogenic carbon is underestimated by analytical uncertainties or if pedogenic processes are responsible for an enrichment of labile- and semi-labile organic carbon in the charcoal-rich RCH soil.

Orthomosaics from aerial photographs play a pivotal role in understanding land-use/land cover in broad area and the advent of image processing technology allows us to produce orthoimagery. However, recent advanced technologies are seldom applied to produce historical orthophotos from early or mid 20C old aerial photos in broad extent since they have limited information (e.g. camera position, flying altitude, and yaw) which is critical information for orthomosaics. In this context, this study aims to orthomosaic and georectify historical aerial photographs and validate the horizontal accuracy of orthomosacicked outputs. In order to achieve this, firstly, we collected 117 aerial photographs of 1934 (scale 1:12,000) and 68 of 1951 (scale 1:20,000) from UConn air photo achieve focused on Woodstock town in Connecticut, USA. Secondly, we created GCPs (Ground Control Points) as referenced points where they have not changed over time by overlaying multiple datasets such as LiDAR DEM, hillshade map, recent orthoimagery. Thirdly, we align photos with Control Points (CPs), build a mesh, and build orthomosaics of 1934 and 1951, respectively, using Agisoft Photoscan 1.5. Lastly, calculating RMSE (Root Mean Square Error) and offsets comparing between set of GCPs and CPs from Lidar DEM and set of them digitized from orthomosaics. As a result, RMSE values of GCPs and CPs between 1934 and 1951 mostly show that output of this work is acceptable to use for standard mapping and GIS work or visualization based on ASPRS 1990 horizonal accuracy standard. In addition, we found several factors affect horizontal accuracy of orthomosaics; resolution of aerial photos, spatial distribution of GCPs and CPs, the number of CPs and GCPs, the percentage of lateral overlapping area along flight strips, and margin area. Overall, applying automated orthomosaicking image processing to historical aerial photographs has the potential to represent historical landscape and even detect its change in broad extent.

Increasing availability and advancements of aerial Light Detection and Ranging (LiDAR) data have radically been shifting the way archeological surveys are performed. Unlike optical remote sensing i...

High resolution airborne Light Detection and Ranging (LiDAR) has become a commonly used resource on a global scale to study landscapes and associated cultural features, especially in areas covered by dense forest. While LiDAR allows for unprecedented views of the terrain beneath the forest canopy, and of landscapes at broad scales generally, few studies have provided an examination of features within theoretical frameworks used to describe landscapes, or have acknowledged LiDAR data as a palimpsest. Any derivative imagery from LiDAR data depicts a moment in time of a contemporary landscape with topographic traces of cultural and physical elements from a range of time periods within and beyond human history. In order to effectively interpret the landscape as represented through LiDAR, it is critical to supplement this data with multiple contextual sources and a more robust theoretical geographic framework. While the concept of landscape as a palimpsest is well known, for the first time in hyper-realistic form we can see and physically interpret that palimpsest, along with the traces of data processing and visualization that we ourselves add to the digital landscape palimpsest in an effort to interpret it. This study provides a critical examination of the LiDAR landscape as a palimpsest, summarizes studies that have used a combination of LiDAR and supplementary resources, and provides observational examples from the northeastern United States, thus providing a practice-based observational and theoretical framework from which other landscapes and associated cultural features can be studied using LiDAR.

Human impacts on earth surface processes and materials are fundamental to understanding the proposed Anthropocene epoch. This study examines the magnitude, distribution, and long-term context of ni...

Landscape evolution modeling and global compilations of exhumation data indicate that a wetter climate, mainly through orographic rainfall, can govern the spatial distribution of erosion rates and crustal strain across an orogenic wedge. However, detecting this link is not straightforward since these relationships can be modulated by tectonic forcing and/or obscured by heavy-tailed frequencies of catchment discharge. This study combines new and published along-strike average rates of catchment erosion constrained by 10Be and river-gauge data in the Central Andes between 28°S and 36°S. These data reveal a nearly identical latitudinal pattern in erosion rates on both sides of the range, reaching a maximum of 0.27 mm/a near 34°S. Collectively, data on topographic and fluvial relief, variability of rainfall and discharge, and crustal seismicity suggest that the along-strike pattern of erosion rates in the southern Central Andes is largely independent of climate, but closely relates to the N–S distribution of shallow crustal seismicity and diachronous surface uplift. The consistently high erosion rates on either side of the orogen near 34°S imply that climate plays a secondary role in the mass flux through an orogenic wedge where the perturbation to base level is similar on both sides. Fil: Val, Pedro. University of California at San Diego; Estados Unidos. Syracuse University; Estados Unidos Fil: Venerdini, Agostina Lia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentina Fil: Ouimet, William. Dept. Of Geography And Center For Integrative Geoscienc; Estados Unidos. University of Connecticut; Estados Unidos Fil: Alvarado, Patricia Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Geofísica y Astronomía; Argentina Fil: Hoke, Gregory D.. Syracuse University; Estados Unidos

Advanced deep learning methods combined with regional, open access, airborne Light Detection and Ranging (LiDAR) data have great potential to study the spatial extent of historic land use features preserved under the forest canopy throughout New England, a region in the northeastern United States. Mapping anthropogenic features plays a key role in understanding historic land use dynamics during the 17th to early 20th centuries, however previous studies have primarily used manual or semi-automated digitization methods, which are time consuming for broad-scale mapping. This study applies fully-automated deep convolutional neural networks (i.e., U-Net) with LiDAR derivatives to identify relict charcoal hearths (RCHs), a type of historical land use feature. Results show that slope, hillshade, and Visualization for Archaeological Topography (VAT) rasters work well in six localized test regions (spatial scale: 15 degrees) (F1 score: 86.8%) compared to coniferous forest and low slope terrain (e.g.

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.

Urban growth consists of horizontal and vertical expansions. An integrative framework for estimating horizontal and vertical expansions of city urban areas using Landsat images was presented. It includes following steps: 1 a spectrum-based classifier here Support Vector Machine is first used to preclassify Landsat images; 2 the spectral similarity-enhanced Markov chain random field cosimulation model is then applied to postclassify the preclassified images and detect building shadows; and 3 a morphological operator based on spatial logic reasoning is used to estimate mid-rise or taller buildings MTBs from detected shadows. Both horizontal urban growth and vertical urban growth in the main city area of Guangzhou for the time period of 1993–2013 were detected. The accuracy of identified MTBs by shadows was validated to be 78.1% on average for 2013. The case study indicates that Guangzhou had undergone both horizontal and vertical urban growth from 1993 to 2013, and vertical urban growth followed horizontal urban growth successively. The relationships between the horizontal and vertical urban growth and three major socioeconomic factors during the studied period were analysed. Results indicate that both the total area of built-up areas and the total area of detected MTBs are significantly correlated with population density, real gross domestic product, and fixed investment i.e. investment in fixed assets such as land, buildings, respectively. While population density is the major driving force of horizontal urban expansion, fixed investment is the major driving force of vertical urban expansion for the city as a whole. Although the method is not perfect currently in detecting MTBs in various situations and the case study is mainly exploratory, the proposed framework and the case study can be helpful in quantitatively exploring the horizontal urban growth and vertical urban growth of a city and their causes.

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 northeast United 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 adjacent Cambisols. Charcoal hearths display two or more 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 northeast United States, with further relevance to other areas where historical charcoal production occurred.

Efforts to extract information about climate and tectonics from topography commonly assume that river networks are static. Drainage divides can migrate through time, however, and recent work has shown that divide mobility can potentially induce changes in river profiles comparable to changes caused by variation in rock uplift, climate, or rock properties. We use 1D river profile and 2D landscape evolution simulations to evaluate how mobile divides influence the interpretation of river profiles in tectonically active settings. We define a non-dimensional divide migration number, NDm, as the ratio of the timescale of channel profile response to a change in drainage area (TdA) to the timescale of divide migration (TDm). In simulations of headward divide migration, NDm is much less than unity with no measurable perturbation of channel profiles. Only in simulations configured to induce rapid lateral divide migration are there occasional large stream capture events and zones where localized drainage area loss is fast enough to support NDm values near unity. The rapid response of channel profiles to changes in drainage area ensures that under most conditions profiles maintain quasi-equilibrium forms and thus generally reflect spatio-temporal variation in rock uplift, climate, or rock properties even during active divide migration. This implies that channel profile form may not reliably record divide mobility, so we evaluate alternate metrics of divide mobility. In our simulations and an example in Taiwan, we find that simple measures of cross-divide contrasts in topography are more robust metrics of divide mobility than measures of drainage network topology.

Relic charcoal hearths (RCHs) have produced distinct legacy effects in forest soils around the world. Recently, LiDAR imagery has revealed thousands of 18th–early 20th century RCHs in Litchfield County, Connecticut, USA; however, the effects of RCHs on a landscape-scale are not well-documented, particularly fine-scale heterogeneity within RCHs and surrounding soils. This study examines the long-term impacts of charcoal production by measuring RCH soil chemical and physical properties from three perspectives: (1) compared to adjacent reference sites (RSadj), (2) laterally at systematic distances away from the RCH center, and (3) vertically within the RCH soil profile. Mean charcoal abundance was greater in RCH sites than RSadj (p

Geometry of planner geological structures can interact with topographic slope and cause different types of slope failure (e.g. wedge failure, dip slope failure, and toppling etc.). This study focus on how the tectonic foliation influences the landslide pattern in the southern Central Range of Taiwan. The tectonic foliations in this area range from pencil cleavage to schistosity depending on the increasing of metamorphic grade, and different foliations have different influences on the landslide behaviors. To describe the relation between foliation and topographic slope, we create the θ D value as the angle between the foliation dip direction azimuth and the topographic downslope direction azimuth at a given location. The location of landslides in the area with pencil cleavage has no preferential θ D value, and it suggests the landslide distribution has no correlation with foliation. The location of landslides in the area with well-developed slaty cleavage is mostly in the lower θ D value, which suggests the landslides are more likely located in the area where the foliation dip direction is parallel to the topographic downslope direction. The location of landslide in the area with schistosity is mostly in the high θ D value area, which suggests the landslides are more likely located in the area where the foliation dip direction is opposite to the topographic downslope direction.

Absent clear lithologic control, the presence of elevated, low-relief topography in upland landscapes has traditionally been interpreted as a signature of relative surface uplift and incision of a paleo-landscape. Such interpretations are commonly supported and quantified using analyses of river longitudinal profiles under the assumption of a static drainage network topology. Drainage networks, however, are not static, and it has been proposed recently that divide migration and drainage capture can lead to the generation of low-relief upland topography that mimics that of incised paleo-landscapes and that might be falsely interpreted as recording surface uplift and/or the onset of accelerated incision. Indeed, the interpretation of the incised southeastern Tibetan Plateau, and thus the associated geodynamic implications, have been called into question. Here we use theory and one- and two-dimensional landscape evolution models to develop a set of morphometric criteria to distinguish these alternative mechanisms of low-relief upland formation. Application to the southeastern Tibetan Plateau illustrates the utility of these metrics and demonstrates that the topography is in no way consistent with the drainage network dynamics mechanism and is fully consistent with incision into an elevated, preexisting low-relief landscape.

In order to understand better if and where erosion rates calculated using in situ 10Be are affected by contemporary changes in land use and attendant deep regolith erosion, we calculated erosion rates using measurements of in situ 10Be in quartz from 52 samples of river sediment collected from three tributaries of the Mekong River (median basin area = 46.5 km2). Erosion rates range from 12 to 209 mm kyr−1 with an area-weighted mean of 117 ± 49 mm kyr−1 (1 standard deviation) and median of 74 mm kyr−1. We observed a decrease in the relative influence of human activity from our steepest and least altered watershed in the north to the most heavily altered landscapes in the south. In the areas of the landscape least disturbed by humans, erosion rates correlate best with measures of topographic steepness. In the most heavily altered landscapes, measures of modern land use correlate with 10Be-estimated erosion rates but topographic steepness parameters cease to correlate with erosion rates. We conclude that, in some small watersheds with high rates and intensity of agricultural land use that we sampled, tillage and resultant erosion has excavated deeply enough into the regolith to deliver subsurface sediment to streams and thus raise apparent in situ 10Be-derived erosion rates by as much as 2.5 times over background rates had the watersheds not been disturbed.

English-style agriculture in the northeastern United States spurred widespread deforestation beginning in the 17th century. Heavy plowing within a rocky, glacial till-mantled landscape resulted in soil erosion and deep frosts. For hundreds of years, stones exposed at the surface due to these processes were built into walls that have become an iconic feature of this landscape, and indicative of past human impacts and land use dynamics in areas that are now reforested. We investigate stone walls in five towns in Connecticut, USA, using airborne Light Detection and Ranging (LiDAR), field measurements, surficial geology maps, and historic agricultural census data. Stone walls are prevalent throughout the study region (∼2113 km over ∼569 km 2 ), but spatial density ranges widely from 0 to 12 km/km 2 . Important controls on the density of stone walls include surficial materials (e.g., ∼4.0 km/km 2 on glacial till compared to 1.5 km/km 2 on floodplain alluvium), and whether land had been “improved” for agriculture (∼5.2 km/km 2 ). The length of stone walls derived from analysis of LiDAR data combined with field measurements (average height of 0.76 ± 0.23 m; width of 0.96 ± 0.50 m), indicates that an average of ∼1.4 × 10 6 m 3 of stone was moved for constructing walls in the study towns alone. Overall, this study highlights the spatial distribution of 17th-20th century agriculture and Anthropocene landscape change in the northeastern USA, providing important implications for human-environment studies in other deglaciated regions of the United States and landscapes with stone-rich soils on a global scale where historic agriculture occurred.

Relict charcoal hearths (RCHs) are anthropogenic geomorphic features with an average diameter of 12 m found in many forests of Central Europe and in the eastern USA wherever pre-coal iron production took place or other industries demanded the production of charcoal. To expand the knowledge about their geoarchaeological significance and their legacy effect on soil properties and forest ecosystems, we propose a method for a generalized description of soil stratigraphy on RCHs. We studied 154 soil profiles at 52 RCH sites alongside two 1 km transects in Litchfield County, Connecticut, USA. The sites can be classified based on the slope inclination, with sites on 4° mostly are built as levelled and multilayered platforms. The latter have two or more charcoal rich technogenic Auh-layers separated by intermediate Auh-layers mostly consisting of mineral substrate. Based on average layer thicknesses and their dependence on the sites slope inclinations, we propose a model with two idealized RCH shapes with slope controlled properties that allow for an easy computation of site diameters and elemental stocks. With ongoing advances in remote sensing of RCH sites, our proposed model can help to further understand the effects of historic land use on a landscape scale.

Analyzing meteoric 10Be in soil profiles along with soil measurements such as pedogenic Fe and clay content permits better understanding of meteoric 10Be transport in soils, soil formation, and hillslope geomorphology. This study presents meteoric 10Be depth profiles from saprolite-derived soil catenas sampled in the Gordon Gulch catchment, Colorado Front Range and from nearby c. 130 and 15 ka glacial moraines. We compare meteoric 10Be data with more classically used soil analyses of clay and extractable iron (Fed) content. Meteoric 10Be and Fed do not show consistent trends in the hillslope profiles. Meteoric 10Be and clay concentrations, however, generally decrease with depth and highest concentrations of 10Be in horizons coincide with highest clay concentrations. Soils at moraine sites are better developed than those on hillslopes, and correlations of 10Be, Fed, and clay are stronger. In Gordon Gulch, south-facing hillslopes display meteoric 10Be bulges at depth and lower near-surface concentrations compared to the declining profiles and higher near-surface concentrations of north-facing hillslopes. The aspect differences imply that south-facing hillslopes experience greater vertical mixing than north-facing hillslopes, and that greater lateral transport and erosion has occurred over the last 15–20 ka on south-facing hillslopes relative to north-facing hillslopes. Meteoric 10Be depth profiles at moraine sites display bulge profiles with highest meteoric 10Be concentrations in B-horizons, reflecting landform stability and pedogenic processes. Overall, our data demonstrate that signatures of chemical weathering in soils (Fed and clay) may or may not correlate to the meteoric 10Be added through atmospheric deposition, and that profile shape of meteoric 10Be can provide insight into the relative contribution of vertical mixing and surface erosion in relation to catena location and aspect during hillslope evolution.

Atmospherically-derived cosmogenic nuclides such as meteoric 10 Be offer great potential in Quaternary science because they can be used as landform geochronometers and as sediment tracers. Use of meteoric 10 Be inventories for determining landform age, soil residence time, or erosion rates requires knowing the long-term rate of deposition for this cosmogenic nuclide to the Earth's surface. Here, we present meteoric 10 Be inventories measured at 6 dated sites near the Boulder Creek Critical Zone Observatory, Front Range, Colorado. Each site lies on a relatively stable landform (broad moraine or fluvial terrace) at slopes between 10 Be deposition (precipitation, dryfall, and dust deposition) calculated from measured inventories at these sites range from 0.4 to 5.0 × 10 6 atoms cm −2 yr −1 ; none of the inventories match expected primary meteoric 10 Be deposition rates that global, latitude-based models or precipitation-specific models predict for this region. Meteoric 10 Be inventories and calculated deposition rates at the three older (>90 ka) sites fall below (0.3–0.7×) model predictions; inventories and rates at the three Pinedale-age sites (LGM; 21–15 ka) are higher (1.5–4×) than model predictions. Previous analysis of soils in the Front Range over the same timeframe as these sites indicate that long-term dust accumulation rates are low and associated secondary meteoric 10 Be deposition is unlikely to account for the deviation from model predictions. At the Pinedale-age sites in particular, long-term dustfall would have to be 1–2 orders of magnitude higher to add the meteoric 10 Be required to account for measured inventories. Low inventories at older sites are consistent with loss of meteoric 10 Be through physical erosion or selective removal of near-surface soil enriched in meteoric 10 Be; time-averaged rates of total meteoric 10 Be deposition for these sites are minima. We speculate that higher inventories at Pinedale-age sites reflect the addition of meteoric 10 Be due to snowdrifts and/or interflow associated with landform location, increasing the effective precipitation-related primary meteoric 10 Be deposition at the sampled sites. Given these constraints, and the spatial variation observed around the Front Range, we suggest that 1.5 ± 0.2 × 10 6 atoms cm −2 yr −1 is an appropriate long-term meteoric 10 Be deposition rate to use across much of the Front Range region that receives 45–55 cm of precipitation a year. This long-term total meteoric 10 Be deposition rate is ∼30–50% higher than that predicted by global or annual precipitation-specific models, emphasizing that local calibration of deposition rates is essential for geomorphic studies around the globe.

In December 2008, 694 trees uprooted within a 108 ha (1·08 km2) watershed in central Massachusetts due to a severe ice storm, resulting in the displacement of ~1300 m3 of root material, unconsolidated sediment, and fractured bedrock. Overall, we find that uprooting and tree throw is often grouped in clusters and cascades; conifers displace more material than deciduous trees; areas with abundant mature hemlock and steep slopes are more susceptible to tree throw, with clusters as dense as 125 per hectare; and failure is predominantly downhill, suggesting that ice storms promote efficient downslope hillslope sediment transport in northern hardwood forests. Combining the recurrence interval of severe storms in New England (20–75 years) with the forest response presented here, we calculate a sediment transport rate of 2–5 × 10−5 m3 m−1 a−1 averaged over the entire watershed. Forest susceptibility to tree throw differed based on location in the watershed; some areas experienced up to ~30× higher than average sediment transport rates, while others experienced no tree throw. Two severe storms following the 2008 ice storm (hurricane in 2011; snow storm in October 2012) did not result in significant tree throw within the study area, highlighting that the coupling of storm severity and forest susceptibility controls the amount of tree throw during a given forest disturbance. In addition to recent tree throw from the 2008 ice storm, widespread pit and mound microtopography in the study area indicates that tree throw is a recurrent process in this landscape. Two factors emerge that will influence future ice storms related hillslope sediment transport in the steep forested hillslopes of New England: regional climate gradients and changing climate determine the size, intensity and recurrence of ice storms; forest management practices and health control the tree age and type. Copyright © 2015 John Wiley & Sons, Ltd.

Cosmogenic radionuclides (CRNs) are commonly employed to quantify both the production rates and residence times of mobile regolith. Meteoric and in situ CRNs have different accumulation mechanisms and can independently constrain landscape evolution rates. Here we use both in situ and meteoric 10 Be to investigate where in the regolith 10 Be is stored, and to quantify production rates and residence times of mobile regolith on active hillslopes in Gordon Gulch, within the Boulder Creek Critical Zone Observatory (CZO), Colorado, USA. Our data reveal that two-thirds of in situ 10 Be in regolith is produced within saprolite, and at least one-tenth of the meteoric 10 Be inventories is stored in saprolite, highlighting the importance of consistent terminology and identification of the mobile regolith–saprolite boundary. We find that mobile-regolith production rates are on average 3.1 cm/k.y., and residence times are between 10 and 20 k.y. A notable exception exists at the depositional north-facing footslope, where residence times likely exceed 40 k.y. Close agreement between the meteoric and in situ results indicates that upper- and mid-slope positions are consistent with steady, uniform lowering of the landscape. In addition to comparing the two methods, we develop a one-dimensional analytical model for the 10 Be concentration fields on an active, steady-state catena with uniform erosion. We then compare model predictions with measurements to evaluate how well our sites adhere to the steady-state assumption underlying the calculations for mobile-regolith residence time and production rates. Such comparisons suggest that calculated residence times and lowering rates are likely no closer than ±25% of the geomorphic reality.

Recently, light detection and ranging (LiDAR) data has been made publicly available for the states of Connecticut, Massachusetts, and Rhode Island in New England, a geographic region in the northeastern United States. Despite the wide range of archaeological studies that have been undertaken with LiDAR on a global scale, few published studies exist in the United States, and no published studies exist for the northeastern US, which has a unique historical and geomorphological landscape. This landscape is densely forested, and archaeological studies in this region highlighting how humans have historically shaped the New England landscape can benefit greatly from the use of LiDAR. This paper contributes to the growing international dialogue regarding the use of LiDAR for archaeological studies by providing examples of features that have been discovered in this region, how these features can be interpreted in conjunction with historical documents and used for reconnaissance surveys, and how these interpretations can contribute to theoretical anthropological perspectives regarding how humans divide and use the landscape. Our analysis has positively identified numerous archaeological sites that have not been previously recorded by archaeological studies.

We used measurements of cosmogenic 10 Be in alluvium to estimate erosion rates on a 10 3 –10 4 yr time scale for small (0.01–47 km 2 ), unglaciated basins in northern Colorado, southern Wyoming, and adjacent western Nebraska (western United States). Basins formed in Proterozoic cores of Laramide ranges are eroding more slowly (23 ± 7 mm k.y. –1 , n = 19) than adjacent basins draining weakly lithified Cenozoic sedimentary rocks (75 ± 36 mm k.y. –1 , n = 20). Erosion rates show a relationship to rock resistance and, for granitic rocks, to basin slope, but not to mean annual precipitation. We estimated longer-term (>10 5 yr time scale) erosion rates for the granitic core of the Front Range by measuring the concentration of 10 Be and 26 Al produced mainly by muon interactions at depths 1.7–10 m below the surface. Concentrations imply erosion rates of 9–31 mm k.y. –1 , similar to shorter-term erosion rates inferred from alluvial sediment. The spatial distribution of erosion rates and stratigraphic evidence imply that relief in the southern Rocky Mountains increased in the late Cenozoic; modern relief probably dates from post-middle Miocene time.

Curves in the topographic grain of active orogenic belts typically parallel faults and lithologic contacts in part because of linkages between uplift rates and the structural development of the overriding plate. However, in the Taiwan collision zone, the topographic grain trends nonparallel to mapped faults and folds in the central portion of the belt along the southwest flank of the Hsuehshan Range. Here, the northern side of the Puli topographic embayment trends ∼345°, forming a topographic break that lies at a high angle to the structural grain but is nearly parallel to an underlying continental margin fracture zone in the downgoing plate. We analyzed fault-slip and other structural data, extracted normalized steepness indices from streams within the Tachia, Peikang, and Mei River basins, and integrated the results with recently published precise leveling data in order to understand the spatial and temporal variation in uplift and the structures that accommodated that uplift. Stress inversion reveals a NW-SE–trending maximum compression direction for an early-stage fault population and an ENE-WSW–trending maximum compression direction for a late-stage fault population. River steepness indices delineate a NW-trending boundary in incision rate that coincides with an increase in rock uplift rates derived from independent geodetic measurements. This NW-trending boundary is consistent with the late-stage maximum compression direction, suggesting that uplift of the Hsuehshan Range relative to the Puli topographic embayment has been accommodated by the late-stage faults. Our results suggest that a continental margin promontory has slowed underplating beneath the Puli topographic embayment and that the topographic grain of active collision zones is closely linked with the architecture of the downgoing plate.

In order to understand better if and where long-term erosion rates calculated using in situ 10Be are affected by contemporary changes in land use and attendant deep regolith erosion, we calculated erosion rates using measurements of in situ 10Be in quartz from 52 samples of river sediment collected from three tributaries of the Mekong River (median basin area = 46.5 km2). Erosion rates range from 12–209 mm/kyr with an area-weighted mean of 117 ± 49 mm/kyr (1 standard deviation) and median of 74 mm/kyr. We observed a decrease in the relative influence of human activity from our steepest and least altered watershed in the north to the most heavily altered landscapes in the south. In the areas of the landscape least disturbed by humans, erosion rates correlate best with measures of topographic steepness. In the most heavily altered landscapes, measures of modern land use correlate with 10Be-estimated erosions rates but topographic steepness parameters cease to correlate with erosion rates. We conclude that in some small watersheds we sampled, those with high rates and intensity of agricultural land use, that tillage and resultant erosion has excavated deeply enough into the regolith to deliver subsurface sediment to streams and thus raise apparent in situ 10Be-derived erosion rates by as much as 2.5 times over background rates had the watersheds not been disturbed.