Forest Clearance Research Articles

SOIL EROSION CAUSED THE INCREASING HOLOCENE RADIOCARBON RESERVOIR EFFECT OF LAKE KANAS IN THE ALTAI MOUNTAINS

ABSTRACTRadiocarbon (14C) dating of the total organic carbon (TOC) content of lacustrine sediments is always affected by a 14C reservoir effect and the 14C dates are often systematically older than the true ages. However, there are few studies of the temporal changes of the 14C reservoir effect, with reference to the specific influencing factors. We collected TOC samples from the Holocene sediments of Lake Kanas, in the southern Altai Mountains, for AMS 14C dating and compared the results with AMS 14C ages based on terrestrial plant macrofossils from the same depths. The results show that the reservoir ages progressively increased from ∼0 to ∼2800 yr between ∼9700 cal BP and ∼530 cal BP. As the lake catchment was glaciated prior to the Holocene, and Holocene soils and peats are the main sources of the TOC in the lake sediments, we argue that soil erosion is the major factor contributing to the progressive increase in the reservoir age. Based on previously reported evidence for increasing moisture in central Asia and glacier advances in the mid-to-late Holocene, we suggest that the intensified soil erosion on the hillslopes was caused by increased precipitation during the mid-to-late Holocene and by anthropogenic forest clearance after 1500 cal BP.

Oleaginous yeasts for biochemicals, biofuels and food from lignocellulose-hydrolysate and crude glycerol.

Microbial lipids produced from lignocellulose and crude glycerol (CG) can serve as sustainable alternatives to vegetable oils, whose production is, in many cases, accompanied by monocultures, land use changes or rain forest clearings. Our projects aim to understand the physiology of microbial lipid production by oleaginous yeasts, optimise the production and establish novel applications of microbial lipid compounds. We have established methods for fermentation and intracellular lipid quantification. Following the kinetics of lipid accumulation in different strains, we found high variability in lipid formation even between very closely related oleaginous yeast strains on both, wheat straw hydrolysate and CG. For example, on complete wheat straw hydrolysate, we saw that one Rhodotorula glutinis strain, when starting assimilatingD-xylosealso assimilated the accumulated lipids, while a Rhodotorula babjevae strain could accumulate lipids onD-xylose.Two strains (Rhodotorula toruloides CBS 14 and R. glutinis CBS 3044) were found to be the best out of 27 tested to accumulate lipids on CG. Interestingly, the presence of hemicellulose hydrolysate stimulated glycerol assimilation in both strains. Apart from microbial oil, R. toruloides also produces carotenoids. The first attempts of extraction using the classical acetone-based method showed that β-carotene is the major carotenoid. However, there are indications that there are also substantial amounts of torulene and torularhodin, which have a very high potential as antioxidants.

Characterizing Transitions between Successional Stages in a Tropical Dry Forest Using LiDAR Techniques

Secondary succession is defined as natural regeneration following complete forest clearance from anthropogenic or natural disturbances. Traditional strategies aimed to map and characterize secondary succession using remote sensing are usually based on deterministic approaches, where transitions between successional stages are not considered. These transitions represent rich environments between successional stages and play a key role in ecosystem regeneration. Here, we evaluate the use of the Full-waveform Airborne LiDAR to characterize changes in forest structure between the transition of early-to-intermediate and intermediate-to-late forest succession at the Santa Rosa National Park Environmental Monitoring Super Site (SRNP-EMSS), Guanacaste, Costa Rica. The vertical forest structure was analyzed on twenty cross-sections selected between forest transitions previously mapped using machine learning; leaf area density (LAD) and waveform metrics were studied based on the waveform profile derived from twenty-seven plots distributed in different successional forest patches. Results suggest that LiDAR techniques can identify forest structure differences between successional stages and their transitions. The significance proves that transitions exist, highlights the unique transitional characteristics between intermediate and late successional stages and contributes to understanding the significance of inter-successional stages (transitions) in secondary dry forests.

Improved Fine-Scale Tropical Forest Cover Mapping for Southeast Asia Using Planet-NICFI and Sentinel-1 Imagery

The accuracy of existing forest cover products typically suffers from “rounding” errors arising from classifications that estimate the fractional cover of forest in each pixel, which often exclude the presence of large, isolated trees and small or narrow forest clearings, and is primarily attributable to the moderate resolution of the imagery used to make maps. However, the degree to which such high-resolution imagery can mitigate this problem, and thereby improve large-area forest cover maps, is largely unexplored. Here, we developed an approach to map tropical forest cover at a fine scale using Planet and Sentinel-1 synthetic aperture radar (SAR) imagery in the Google Earth Engine platform and used it to map all of Southeastern Asia’s forest cover. The machine learning approach, based on the Random Forests models and trained and validated using a total of 37,345 labels collected from Planet imagery across the entire region, had an accuracy of 0.937 and an F1 score of 0.942, while a version based only on Planet imagery had an accuracy of 0.908 and F1 of 0.923. We compared the accuracy of our resulting maps with 5 existing forest cover products derived from medium-resolution optical-only or combined optical-SAR approaches at 3,000 randomly selected locations. We found that our approach overall achieved higher accuracy and helped minimize the rounding errors commonly found along small or narrow forest clearings and deforestation frontiers where isolated trees are common. However, the forest area estimates varied depending on topographic location and showed smaller differences in highlands (areas >300 m above sea level) but obvious differences in complex lowland landscapes. Overall, the proposed method shows promise for monitoring forest changes, particularly those caused by deforestation frontiers. Our study also represents one of the most extensive applications of Planet imagery to date, resulting in an open, high-resolution map of forest cover for the entire Southeastern Asia region.

Civil War Obscura: Miss Ravenel's Conversion from Secession to Loyalty

Meg Groeling shows that John William De Forest's Miss Ravenel's Conversion from Secession to Loyalty is an important wartime novel for its unvarnished portrayal of war. "It was one of the first novels to depict war realistically, with blood, gore, illness, and heartbreak," Groeling explains. Beyond its pathbreaking portrayal of war, the book's Civil War era "Easter eggs" will make it a gratifying read for Civil War buffs.

Novi lokaliteti vrste Cirsium candelabrum (Asteraceae) u Hrvatskoj

Cirsium candelabrum is a Balkan endemic species, non-indigenous to Croatia. In the last 13 years its spread was observed only in Central Dalmatia. From 2015 to 2021 we have been recording its invasive spreading across the Kvarner region and its arrival to the southern edge of Gorski Kotar. The plants appear in diverse numbers in two different habitat types. In the sub-Mediterranean zone, the species inhabits ruderal habitats arising from the degradation of the natural vegetation by the construction works for traffic and communal infrastructure and the erection of industrial zones and shopping centres, accompanied by numerous invasive alien species. In the upper (montane and subalpine) zone of Mali and Veliki Platak, C. candelabrum dominates in stands on gravely road edges, forest ways, on incisions with glacial till, and especially luxuriant and dense populations form on the dug-up soil under the ski lift and along the ski run on Radeševo. Here, C. candelabrum is accompanied by native species characteristic for the forest edges and clearings and sometimes for ruderal, chasmophytyc or scree habitats.

Cutmarked bone of drought-tolerant extinct megafauna deposited with traces of fire, human foraging, and introduced animals in SW Madagascar

People could have hunted Madagascar’s megafauna to extinction, particularly when introduced taxa and drought exacerbated the effects of predation. However, such explanations are difficult to test due to the scarcity of individual sites with unambiguous traces of humans, introduced taxa, and endemic megaherbivores. We excavated three coastal ponds in arid SW Madagascar and present a unique combination of traces of human activity (modified pygmy hippo bone, processed estuarine shell and fish bone, and charcoal), along with bones of extinct megafauna (giant tortoises, pygmy hippos, and elephant birds), extirpated fauna (e.g., crocodiles), and introduced vertebrates (e.g., zebu cattle). The disappearance of megafauna from the study sites at ~ 1000 years ago followed a relatively arid interval and closely coincides with increasingly frequent traces of human foraging, fire, and pastoralism. Our analyses fail to document drought-associated extirpation or multiple millennia of megafauna hunting and suggest that a late combination of hunting, forest clearance, and pastoralism drove extirpations.

Comparative Evaluation of Mobile Platforms for Non-Structured Environments and Performance Requirements Identification for Forest Clearing Applications

The effort to automate is present across all industries. It has an economic purpose but potential impacts go far beyond economics. Research has been carried out and a lot of investment has been made in automation in a variety of industries, as well as in agriculture and forestry, which resulted in efficient solutions for diverse applications. In fact, more solutions have emerged in the field of agriculture than in any other. This can be explained in economic terms, but also in light of the complex navigation required because of unstructured environments such as forests. This paper provides a comprehensive review of existing mobile platforms and presents a comparative study for an application in forest clearing. We evaluate the size, automation levels, traction, energy source, locomotion systems, sensors/actuators availability and tools that such an application must have to succeed in its function. Hence, it will be possible to evaluate the feasibility of retrofitting an existing platform into an electric unmanned ground vehicle for forest clearing or if it is easier to start development from scratch. The evaluation results reveal that an electric unmanned ground vehicle for forest clearing is currently unavailable in the market and that a new platform is needed. The performance requirements for such a platform are identified and proposed in the paper.

Роберт Милликен и его роль в рождении современных радиоламп

The article focuses on the work of Harold Wilson, Robert Millikan and his students, in particular, Louis Begeman and Harvey Fletcher on determining the magnitude of an elementary electric charge. Attention is drawn to the priority of authorship in the publications of R. Millikan and H. Fletcher based on the results of joint research. A controversy was noted around the results of Millikan’s experiments to determine the electric charge of an electron. The situation with R. Millikan’s recommendation of his student Harold de Forest Arnold to the WECo research group for the development of a telephone electronic repeater is described.

Canopy openness modifies tree seedling distributions along a tropical forest elevation gradient

In theory, canopy openings can influence tree species establishment and resulting distributions over environmental gradients, but evidence concerning the magnitude and direction of such effects remain scarce. In this study we examine how canopy openings influence seedling persistence and growth and resulting elevation range limits. We transplanted 1360 seedlings of eight woody species (trees Trichilia habanensis, Persea caerulea, Cedrela tonduzii, Cornus disciflora, Quercus salicifolia, Q. bumelioides, Q. costaricensis and the shrub Hypericum irazuense) under the forest canopy and in open areas with understorey vegetation removed in a replicated design along a 2900 m elevation gradient in Costa Rica. We recorded survival, stem diameter and height over 18 months. We used hierarchical generalized additive models to examine relationships of seedling survival and growth with elevation and treatment (inside forest versus open area). We found a clear effect of open versus forest conditions on survival across the elevation gradient for six species. Species planted into open areas with full light exposure survived 100–1000 m below (~ 0.5–5°C warmer), and in one case 300 m above (~ 1.8°C colder) their observed ranges. Above 2900 m, survival of all species was markedly greater under the forest canopy versus open sites, suggesting facilitation from the forest, as frost occurred in open areas above this elevation. The resulting upper range increased between 200 and 1160 m (~ 1–6°C colder) compared to their observed range. At lower elevations, severe insect herbivory occurred on some species likely influencing lower range limits. Open areas influenced how seedling survival and growth varied with elevation for all the studied species. All species survived and grew outside the elevation ranges where they are typically observed. We suggest that the influence of forest gaps and clearings over extended gradients offers novel insights into tree range dynamics, limits and conservation.

Effectiveness of the obligation of keeping forest strips for native forest connectivity and conservation in the dry Chaco, Argentina

Aim of study: The Chaco Region is one of the main deforestation hotspots in Latin America. Forest strips, i.e. native forest strips that surround cultivated areas, were established by the end of 1980’s as an attempt to mitigate the effects of wind erosion and as a way of conserving and interconnecting the remaining native forest patches. The aim of this study is to assess the effectiveness of the scheme for the authorization of new agricultural land in the conservation of native forests.
 Area of study: The most recent nuclei of agricultural expansion in the provinces of Chaco, Santiago del Estero, Salta and Formosa, Argentina.
 Materials and methods: Landscape structure, forest connectivity and compliance with the obligation of leaving forest strips was assessed in satellite images for the years 1988 and 2015 within a Geographic Information System.
 Main results: Forest strips differ from other forest patches in structure, presenting a greater perimeter/area ratio and smaller mean size. A great loss of landscape connectivity, lower than expected compliance of regulations and few forest strips with the minimum mandatory width were observed. Notable differences between provinces were found.
 Research highlights: Forest strips would not be effective to conserve and interconnect the native forest patches. In light of new land clearings, other alternatives should be proposed in which the remaining forest persists as few large fragments with landscape and extra-landscape scale interconnection and minimizing the edge effect.

Monitoring dryland trees with remote sensing. Part B: Combining tree cover and plant architecture data to assess degradation and recovery of Argania spinosa woodlands of South Morocco

The argan woodlands of South Morocco represent an open-canopy dryland forest with traditional silvopastoral usage that includes browsing by goats, sheep and camels, oil production as well as agricultural use. In the past, these forests have undergone extensive clearing, but are now protected by the state. However, the remaining argan woodlands are still under pressure from intensive grazing and illegal firewood collection. Although the argan-forest area seems to be overall decreasing due to large forest clearings for intensive agriculture, little quantitative data is available on the dynamics and overall state of the remaining argan forest. To determine how the argan woodlands in the High Atlas and the Anti-Atlas had changed in tree-crown cover from 1972 to 2018 we used historical black and white HEXAGON satellite images as well as recent WorldView satellite images (see Part A of our study). Because tree shadows can oftentimes not be separated from the tree crown on panchromatic satellite images, individual trees were mapped in three size categories to determine if trees were unchanged, had decreased/increased in crown size or had disappeared or newly grown. The current state of the argan trees was evaluated by mapping tree architectures in the field. Tree-cover changes varied highly between the test sites. Trees that remained unchanged between 1972 and 2018 were in the majority, while tree mortality and tree establishment were nearly even. Small unchanged trees made up 48.4% of all remaining trees, of these 51% showed degraded tree architectures. 40% of small (re-) grown trees were so overbrowsed that they only appeared as bushes, while medium (3–7 m crown diameter) and large trees (>7 m) showed less degraded trees regardless if they had changed or not. Approaches like grazing exclusion or cereal cultivation lead to a positive influence on tree architecture and less tree-cover decrease. Although the woodland was found to be mostly unchanged 1972–2018, the analysis of tree architecture reveals that a lot of (mostly small) trees remained stable but in a degraded state. This stability might be the result of the small trees’ high degradation status and shows the heavy pressure on the argan forest.

Adaptive Audacity: Uncovering Queer Attachments and Re-evaluating Marriage Narratives in John William De Forest's Miss Ravenel's Conversion from Secession to Loyalty

Adaptive Audacity: Uncovering Queer Attachments and Re-evaluating Marriage Narratives in John William De Forest's <i>Miss Ravenel's Conversion from Secession to Loyalty</i>

Cenopopulations of Adonis wolgensis Stev. in the conditions of Northern Kazakhstan

The article presents the study results on the cenopopulations of Adonis wolgensis in Northern Kazakhstan (2019–2021). The materials are obtained as a result of field research; literary data are considered. Based on detailed route studies, the structure of cenopopulations is given. Nine cenopopulations located in the Kostanay region are studied. Populations of A. wolgensis occupy areas from 300 to 1000 m2. The largest total projective cover is noted in forest clearings and along the outskirts of forests. The proportion of A. wolgensis in the total projective cover there is 1–5 %. The studied cenopopulations are characterized by contagious and random types of distribution of individuals in space; a uniform (regular) type is not recorded. An assessment of the vitality type of cenopopulations shows that five of the studied cenopopulations have a normal vitality type and four flourishing ones. Cenopopulations that are in an oppressed, depressed, and infertile states are not found.

How do land cover changes affect carbon-nitrogen-phosphorus stocks and the greenhouse gas budget of ecosystems in southern Chile?

Agricultural land use changes are expected to modify the carbon (C), nitrogen (N) and phosphorus (P) stocks compared to the native ecosystems they replace and result in changes in greenhouse gas (GHG) fluxes. To quantify these effects, we measured C-N-P stocks in four land cover classes (cropland, grassland, native shrubland and invaded shrubland) together with their ecosystem-level CO2, CH4 and N2O fluxes for one year using the closed-chamber technique, in three locations on Chiloé Island, southern Chile. As a reference, given that most of the original ecosystems were derived from forest clearance, we monitored CO2 fluxes in a native forest site in the same area using the eddy covariance technique, and used published data of its C-N-P stocks and CH4 and N2O fluxes. We found that compared to the forest, the other land cover classes represented a 60 % loss of total ecosystem C, which was explained mainly by the loss of 98 % in above ground biomass and a 42 % reduction in soil C, but with a relatively unchanged N stock and an increase in soil P. While croplands were net GHG emitters (901 g CO2-eq m-2 year-1), grasslands, native shrublands and invaded shrublands were net sinks (−1350, −1154 and −2088 g CO2-eq m-2 year-1, respectively). The invaded shrublands (invaded by the N-fixing species Ulex europaeus and Cytisus scoparius) showed higher aboveground and root biomass compared to the other land cover classes, but somewhat lower C-N-P soil stocks, possibly because of lower litter decomposition, reduced root turnover/rhizodeposition and/or greater dissolved elemental losses, as the invasion occurred on degraded lands. Although the invasive shrublands acted as a stronger GHG sink, driven by their higher CO2 fixation, this might change in the longer term through the additional accumulation of fixed N, with a potential increase in N2O emissions.

River flooding on the French Mediterranean coast and its relation to climate and land use change over the past two millennia

River flooding triggered by extreme rainfall events is a major natural hazard that frequently causes fatalities and damages in southeastern France. A 2000-year record of flooding from the Hérault River basin was reconstructed using magnetic susceptibility data from lagoon deposits, supported by documentary databases of floods in coastal river basins from Languedoc over the last centuries. Flooding was particularly important between 800 and 1350 cal CE, i.e. during the warm climatic conditions of the Medieval Climate Anomaly. Moreover, several periods of increased flooding occurred in the 2nd, 6th-7th, 16th, 18th and 20th centuries. Increased flooding was significantly correlated with higher air temperature in the northwestern Mediterranean and with higher sea surface temperature in the Gulf of Lions. The analysis of relationships between river flooding and atmospheric conditions shows that autumn flood events in Languedoc were generally more frequent during the positive phase of the East Atlantic pattern, which is associated with southerly to southeasterly winds in the Gulf of Lions. Besides, increased flooding could also have been controlled by forest decline and human activities after 500 cal CE. Between 1400 and 1800 cal CE, palaeobotanical data show an intensification of land use characterized by an expansion of grasslands and cultivated areas in the coastal lowlands east of the Hérault River. Forest clearings and the development of agriculture seem to have led to a relative increase in river flooding, especially in the late Middle Ages and early modern period.

What can the Glasgow Declaration on Forests bring to global emission reduction?

What can the Glasgow Declaration on Forests bring to global emission reduction?

A New Subspecies of Dianthus pseudarmeria (Caryophyllaceae) from Turkey

The samples collected from the Pınarhisar district (Kırklareli, Turkey) were introduced as a new subspecies for the scientific world. Dianthus pseudarmeria subsp. glabripetalus grows in oak forest clearings with an altitude of about 250-350 meters. The new subspecies are similar in terms of many vegetative and generative characters with D. pseudarmeria (subsp. pseudarmeria). However, the new subspecies differs from D. pseudarmeria (subsp. pseudarmeria) by the fact that scales of the epicalyx are striped-lanceolate or reverse-lanceolate and the petal limbin is glabrous. Conclusively, description of the subspecies, seed morphology, descriptive and explain photos, distribution, general ecological preferences are given. In addition, a suitable category of threats to the conservation of the subspecies is proposed in light of the available data.

Linking land-use and land-cover transitions to their ecological impact in the Amazon

Human activities pose a major threat to tropical forest biodiversity and ecosystem services. Although the impacts of deforestation are well studied, multiple land-use and land-cover transitions (LULCTs) occur in tropical landscapes, and we do not know how LULCTs differ in their rates or impacts on key ecosystem components. Here, we quantified the impacts of 18 LULCTs on three ecosystem components (biodiversity, carbon, and soil), based on 18 variables collected from 310 sites in the Brazilian Amazon. Across all LULCTs, biodiversity was the most affected ecosystem component, followed by carbon stocks, but the magnitude of change differed widely among LULCTs and individual variables. Forest clearance for pasture was the most prevalent and high-impact transition, but we also identified other LULCTs with high impact but lower prevalence (e.g., forest to agriculture). Our study demonstrates the importance of considering multiple ecosystem components and LULCTs to understand the consequences of human activities in tropical landscapes.

The building of palisades and palisaded castles in Ottoman Hungary – Case studies

Abstract During the period of Ottoman rule in Hungary (1541‒1686), palisaded castles of differing sizes were typical elements in the border-castle networks on both sides of the battlefront: the Ottoman and the Christian. Archaeological remains (post-holes, beam structures, parts of palisades) complement the data in the written sources, making perceptible and measurable the great quantities of timber used in the building of castles. In the case of the Ottoman palisaded castle at Barcs and in that of the royal palisaded castle at Bajcsavár (southern Transdanubia), attempts were made ‒ on the basis of archaeological observations and reconstructions of ground plans ‒ to determine the number of palisade stakes used for the walls at the time of building, as well as to establish the number of trees felled in order to make them. By way of environmental history researches, an answer was sought to the question of how much the construction of these palisaded castles impacted on the forests in their respective districts. In the case of Barcs Castle, investigations were conducted into whether forest clearance in its vicinity can be reconstructed on the basis of pollen samples. Other issues examined are how far forest clearance extended from the two fortifications, its intensity, and the approximate quantities of timber yielded by it.