scholarly journals Expansion of Eastern Redcedar (Juniperus virginiana L.) into the Deciduous Woodlands within the Forest–Prairie Ecotone of Kansas

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 154 ◽  
Author(s):  
G. A. Pabodha Galgamuwa ◽  
Jida Wang ◽  
Charles J. Barden
Keyword(s):  
Temporal Dynamics ◽  
Control Measures ◽  
Rapid Expansion ◽  
Deciduous Forests ◽  
Support Vector ◽  
Juniperus Virginiana ◽  
Eastern Redcedar ◽  
Growing Stock ◽  
Quercus Species ◽  
Spatio Temporal

North America’s midcontinent forest–prairie ecotone is currently exhibiting extensive eastern redcedar (ERC) (Juniperus virginiana L.) encroachment. Rapid expansion of ERC has major impacts on the species composition and forest structure within this region and suppresses previously dominant oak (Quercus) species. In Kansas, the growing-stock volume of ERC increased by 15,000% during 1965–2010. The overarching goal of this study was to evaluate the spatio-temporal dynamics of ERC in the forest–prairie ecotone of Kansas and understand its effects on deciduous forests. This was achieved through two specific objectives: (i) characterize an effective image classification approach to map ERC expansion, and (ii) assess ERC expansion between 1986 and 2017 in three study areas within the forest–prairie ecotone of Kansas, and especially expansion into deciduous forests. The analysis was based on satellite imagery acquired by Landsat TM and OLI sensors during 1986–2017. The use of multi-seasonal layer-stacks with a Support Vector Machine (SVM)-supervised classification was found to be the most effective approach to classify ERC distribution with high accuracy. The overall accuracies for the change maps generated for the three study areas ranged between 0.95 (95 CI: ±0.02) and 0.96 (±0.03). The total ERC cover increased in excess of 6000 acres in each study area during the 30-year period. The estimated percent increase of ERC cover was 139%, 539%, and 283% for the Tuttle Creek reservoir, Perry reservoir, and Bourbon County north study areas, respectively. This astounding rate of expansion had significant impacts on the deciduous forests where the conversion of deciduous woodlands to ERC, as a percentage of the total encroachment, were 48%, 56%, and 71%, for the Tuttle Creek reservoir, Perry reservoir, and Bourbon County north study areas, respectively. These results strongly affirm that control measures should be implemented immediately to restore the threatened deciduous woodlands of the region.

scholarly journals Comparing Grazed and Ungrazed Forests in Kansas

1998 ◽  
Vol 15 (4) ◽  
pp. 216-221 ◽  
Author(s):  
Thomas L. Schmidt ◽  
Mark H. Hansen
Keyword(s):  
Decision Making ◽  
Forest Type ◽  
Deciduous Forests ◽  
Decision Making Process ◽  
Juniperus Virginiana ◽  
Bare Ground ◽  
Eastern Redcedar ◽  
Growing Stock ◽  
Hardwood Species ◽  
Stock Volume

Abstract Differences between grazed and ungrazed forestlands in Kansas were investigated based on a statewide sample of all forestlands. Grazing forestlands was found to have a significant relationship to the quality and quantity of trees on forestlands, as seen in lower levels of total volume and growing-stock volume when compared to ungrazed forestlands. In addition, grazed forestlands showed lower average basal areas, younger average stand ages, lower potential productivities, and increased percentages of bare ground. Compared to forestlands without grazing, forestlands with grazing had higher levels of eastern redcedar (Juniperus virginiana L.) seedling regeneration and lower levels of preferred hardwood species regeneration in several forest type groups. Land managers can use these results in their decision-making process concerning whether to graze their deciduous forests. North. J. Appl. For. 15(4):216-221.

Dynamic Changes in the Mental Rotation Network Revealed by Pattern Recognition Analysis of fMRI Data

2009 ◽  
Vol 21 (5) ◽  
pp. 890-904 ◽  
Author(s):  
Janaina Mourao-Miranda ◽  
Christine Ecker ◽  
Joao R. Sato ◽  
Michael Brammer
Keyword(s):  
Pattern Recognition ◽  
Functional Connectivity ◽  
Mental Rotation ◽  
Temporal Dynamics ◽  
Parietal Lobe ◽  
Time Window ◽  
Support Vector ◽  
Dynamic Changes ◽  
Angular Disparity ◽  
Spatio Temporal

We investigated the temporal dynamics and changes in connectivity in the mental rotation network through the application of spatio-temporal support vector machines (SVMs). The spatio-temporal SVM [Mourao-Miranda, J., Friston, K. J., et al. (2007). Dynamic discrimination analysis: A spatial-temporal SVM. Neuroimage, 36, 88–99] is a pattern recognition approach that is suitable for investigating dynamic changes in the brain network during a complex mental task. It does not require a model describing each component of the task and the precise shape of the BOLD impulse response. By defining a time window including a cognitive event, one can use spatio-temporal fMRI observations from two cognitive states to train the SVM. During the training, the SVM finds the discriminating pattern between the two states and produces a discriminating weight vector encompassing both voxels and time (i.e., spatio-temporal maps). We showed that by applying spatio-temporal SVM to an event-related mental rotation experiment, it is possible to discriminate between different degrees of angular disparity (0° vs. 20°, 0° vs. 60°, and 0° vs. 100°), and the discrimination accuracy is correlated with the difference in angular disparity between the conditions. For the comparison with highest accuracy (0° vs. 100°), we evaluated how the most discriminating areas (visual regions, parietal regions, supplementary, and premotor areas) change their behavior over time. The frontal premotor regions became highly discriminating earlier than the superior parietal cortex. There seems to be a parcellation of the parietal regions with an earlier discrimination of the inferior parietal lobe in the mental rotation in relation to the superior parietal. The SVM also identified a network of regions that had a decrease in BOLD responses during the 100° condition in relation to the 0° condition (posterior cingulate, frontal, and superior temporal gyrus). This network was also highly discriminating between the two conditions. In addition, we investigated changes in functional connectivity between the most discriminating areas identified by the spatio-temporal SVM. We observed an increase in functional connectivity between almost all areas activated during the 100° condition (bilateral inferior and superior parietal lobe, bilateral premotor area, and SMA) but not between the areas that showed a decrease in BOLD response during the 100° condition.

scholarly journals Impact of Pruning Eastern Redcedar (Juniperus virginiana)

2002 ◽  
Vol 17 (4) ◽  
pp. 189-193 ◽  
Author(s):  
Thomas L. Schmidt ◽  
Tom D. Wardle
Keyword(s):  
South Dakota ◽  
Great Plains ◽  
Wood Quality ◽  
Ground Level ◽  
Control Measures ◽  
Juniperus Virginiana ◽  
Eastern Redcedar ◽  
Total Height ◽  
Forest Industries ◽  
Future Utilization

Abstract In recent years, eastern redcedar has been the most rapidly expanding tree resource in the Great Plains from Oklahoma to South Dakota, primarily in rangelands and pastures. Based on these increases and potential management-related problems, eastern redcedar is perceived as a threat to the rangeland resource. Pruning eastern redcedar can allow for increased herbaceous growth under the eastern redcedar's crown, improve livestock handling, maintain the species for diversity and habitat contributions, and improve wood quality for potential future utilization by forest industries. To determine the effect of pruning to different heights on tree growth, we compared unpruned trees' total height and diameter to trees pruned from ground level to heights of 60, 90, 120, and 150 cm. No significant differences in the total height were found for all pruning treatments over all time periods. After more than 10 yr, trees pruned to 60, 90, and 120 cm had smaller diameters at ground level than unpruned trees. There were no differences in ground diameters for trees pruned to 150 cm compared to unpruned trees after 4 yr of growth. There were no significant differences in dbh for eastern redcedar trees pruned to all heights. Management of eastern redcedar, including pruning, is recommended as an alternative to control measures. West. J. Appl. For. 17(4):189–193.

scholarly journals Evaluation of Using Sentinel-1 and -2 Time-Series to Identify Winter Land Use in Agricultural Landscapes

2018 ◽  
Vol 11 (1) ◽  
pp. 37 ◽  
Author(s):  
Julien Denize ◽  
Laurence Hubert-Moy ◽  
Julie Betbeder ◽  
Samuel Corgne ◽  
Jacques Baudry ◽  
...  
Keyword(s):  
Land Use ◽  
Time Series ◽  
Vegetation Cover ◽  
Temporal Dynamics ◽  
Agricultural Practices ◽  
Agricultural Landscapes ◽  
Support Vector ◽  
Kappa Index ◽  
Spatio Temporal ◽  
Agricultural Areas

Monitoring vegetation cover during winter is a major environmental and scientific issue in agricultural areas. From an environmental viewpoint, the presence and type of vegetation cover in winter influences the transport of pollutants to water resources. From a methodological viewpoint, characterizing spatio-temporal dynamics of land cover and land use at the field scale is challenging due to the diversity of farming strategies and practices in winter. The objective of this study was to evaluate the respective advantages of Sentinel optical and SAR time-series to identify land use in winter. To this end, Sentinel-1 and -2 time-series were classified using Support Vector Machine and Random Forest algorithms in a 130 km² agricultural area. From the classification, the Sentinel-2 time-series identified winter land use more accurately (overall accuracy (OA) = 75%, Kappa index = 0.70) than that of Sentinel-1 (OA = 70%, Kappa = 0.66) but a combination of the Sentinel-1 and -2 time-series was the most accurate (OA = 81%, Kappa = 0.77). Our study outlines the effectiveness of Sentinel-1 and -2 for identify land use in winter, which can help to change agricultural practices.

scholarly journals Spatio-temporal dynamics of face perception

2019 ◽  
Author(s):  
I. Muukkonen ◽  
K. Ölander ◽  
J. Numminen ◽  
V.R. Salmela
Keyword(s):  
Temporal Dynamics ◽  
Theoretical Models ◽  
Brain Regions ◽  
Support Vector ◽  
Functional Roles ◽  
Emotional Distance ◽  
Early Visual Cortex ◽  
Spatio Temporal ◽  
Information Matrices ◽  
Combine Information

AbstractThe temporal and spatial neural processing of faces have been studied rigorously, but few studies have unified these dimensions to reveal the spatio-temporal dynamics postulated by the models of face processing. We used support vector machine decoding and representational similarity analysis to combine information from different locations (fMRI), timepoints (EEG), and theoretical models. By correlating information matrices derived from pair-wise decodings of neural responses to different facial expressions (neutral, happy, fearful, angry), we found early EEG timepoints (110-150 ms) to match fMRI data from early visual cortex (EVC), and later timepoints (170 – 250 ms) to match data from occipital and fusiform face areas (OFA/FFA) and posterior superior temporal sulcus (pSTS). The earliest correlations were driven by information from happy faces, and the later by more accurate decoding of fearful and angry faces. Model comparisons revealed systematic changes along the processing hierarchy, from emotional distance and visual feature coding in EVC to coding of intensity of expressions in right pSTS. The results highlight the importance of multimodal approach for understanding functional roles of different brain regions.

scholarly journals Pattern of Growth of Sapwood, Heartwood, and Stem Volume of Open-Grown Eastern Redcedar in Grasslands

1998 ◽  
Vol 22 (3) ◽  
pp. 169-174 ◽  
Author(s):  
Dejene Alemayehu ◽  
David M. Engle ◽  
Robert F. Wittwer ◽  
Steve Anderson
Keyword(s):  
Control Measures ◽  
Tree Age ◽  
Stem Volume ◽  
Juniperus Virginiana ◽  
Exponential Rate ◽  
Eastern Redcedar ◽  
Commercial Harvest ◽  
Management Alternative ◽  
Relationship Of ◽  
The Relationship

Abstract The relationship of sapwood width, heartwood width, and stem volume with tree age was studied in 141 open-grown eastern redcedar (Juniperus virginiana L.) trees in central, eastern, and western Oklahoma. The rate of growth of sapwood and heartwood and the increase in stem volume were slow up to 15 to 20 yr of age and increased thereafter at an exponential rate until about age 27. These data reinforce the recommendation that control measures applied to invading eastern redcedar should be taken when the trees are less than about 10 yr old or less than 2 m tall. Allowing the trees to grow for commercial harvest may present a management alternative after the trees are 15 to 20 yr old. South. J. Appl. For. 22(3):169-174.

scholarly journals Using hypertemporal Sentinel-1 data to predict forest growing stock volume

2021 ◽  
Author(s):  
Shaojia Ge ◽  
Erkki Tomppo ◽  
Yrjö Rauste ◽  
Ronald E. McRoberts ◽  
Jaan Praks ◽  
...  
Keyword(s):  
Time Series ◽  
Prediction Accuracy ◽  
Temporal Dynamics ◽  
Support Vector ◽  
List Type ◽  
Prediction Errors ◽  
Growing Stock ◽  
Reduction Techniques ◽  
Combined Images ◽  
Stock Volume

AbstractIn this study, we assess the potential of long time series of Sentinel-1 SAR data to predict forest growing stock volume and evaluate the temporal dynamics of the predictions. The boreal coniferous forests study site is located near the Hyytiälä forest station in central Finland and covers an area of 2,500 km2 with nearly 17,000 stands. We considered several prediction approaches (linear, support vector and random forests regression) and fine-tuned them to predict growing stock volume in several evaluation scenarios. The analyses used 96 Sentinel-1 images acquired over three years. Different approaches for aggregating SAR images and choosing feature (predictor) variables were evaluated. Our results demonstrate considerable decrease in RMSEs of growing stock volume as the number of images increases. While prediction accuracy using individual Sentinel-1 images varied from 85 to 91 m3/ha RMSE (relative RMSE 50-53%), RMSE with combined images decreased to 75.6 m3/ha (relative RMSE 44%). Feature extraction and dimension reduction techniques facilitated achieving the near-optimal prediction accuracy using only 8-10 images. When using assemblages of eight consecutive images, the GSV was predicted with the greatest accuracy when initial acquisitions started between September and January.HighlightsTime series of 96 Sentinel-1 images is analysed over study area with 17,762 forest stands.Rigorous evaluation of tools for SAR feature selection and GSV prediction.Improved periodic seasonality using assemblages of consecutive Sentinel-1 images.Analysis of combining images acquired in “frozen” and “dry summer” conditions.Competitive estimates using calculation of prediction errors with stand-area weighting.

scholarly journals The early dynamics of the SARS-CoV-2 epidemic in Portugal

2021 ◽  
Author(s):  
V Borges ◽  
J Isidro ◽  
NS Trovão ◽  
S Duarte ◽  
H Cortes-Martins ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Control Measures ◽  
Travel History ◽  
Genomic Epidemiology ◽  
The United Kingdom ◽  
Health Authorities ◽  
Public Health Authorities ◽  
Spatio Temporal ◽  
Portuguese Immigrants ◽  
And Control

ABSTRACTBackgroundGenomic surveillance of SARS-CoV-2 in Portugal was rapidly implemented by the National Institute of Health in the early stages of the COVID-19 epidemic, in collaboration with more than 50 laboratories distributed nationwide. This unprecedented collaborative effort culminated in the generation of 1275 SARS-CoV-2 genome sequences, which represent 15.5% of all confirmed cases in March 2020, making Portugal one of the countries generating the highest volumes of SARS-CoV-2 genomic data during early COVID-19 pandemic.MethodsWe reconstructed and characterized the spatio-temporal dynamics of SARS-CoV-2 introductions and early dissemination in Portugal using recent phylodynamic models that allow integration of individual-based travel history, in order to obtain a more realistic reconstruction of the viral dynamics.ResultsWe detected at least 277 independent SARS-CoV-2 introductions, mostly from European countries (namely the United Kingdom, Spain, France, Italy and Switzerland), which was broadly consistent with the available travel history data, as well as with the countries with most frequent connectivity and/or with the highest number of Portuguese immigrants. Although most introductions were estimated to have occurred during the last week of February and the first week of March 2020, it is likely that SARS-CoV-2 was silently circulating in Portugal several weeks before the first confirmed local cases on March 2, 2020.Discussion and ConclusionWhile the implemented preventive and early control measures seem to have been successful in mitigating community transmission from most independent introductions, our results suggest that their earlier implementation could have largely minimized the number of introductions and subsequent virus expansion. Here we lay the foundation for genomic epidemiology of SARS-CoV-2 in Portugal, and highlight the need for systematic, continuous and geographically-representative genomic surveillance to guide national and international public health authorities toward the characterization and control of SARS-CoV-2 circulating diversity.

scholarly journals Describing fine spatiotemporal dynamics of rat fleas in an insular ecosystem enlightens abiotic drivers of murine typhus incidence in humans

2021 ◽  
Vol 15 (2) ◽  
pp. e0009029
Author(s):  
Annelise Tran ◽  
Gildas Le Minter ◽  
Elsa Balleydier ◽  
Anaïs Etheves ◽  
Morgane Laval ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Disease Transmission ◽  
Temporal Dynamics ◽  
Abiotic Factors ◽  
Incidence Rates ◽  
Control Measures ◽  
Support Vector ◽  
Public Health Services ◽  
Murine Typhus ◽  
Flea Infestation

Murine typhus is a flea-borne zoonotic disease that has been recently reported on Reunion Island, an oceanic volcanic island located in the Indian Ocean. Five years of survey implemented by the regional public health services have highlighted a strong temporal and spatial structure of the disease in humans, with cases mainly reported during the humid season and restricted to the dry southern and western portions of the island. We explored the environmental component of this zoonosis in an attempt to decipher the drivers of disease transmission. To do so, we used data from a previously published study (599 small mammals and 175 Xenopsylla fleas from 29 sampling sites) in order to model the spatial distribution of rat fleas throughout the island. In addition, we carried out a longitudinal sampling of rats and their ectoparasites over a 12 months period in six study sites (564 rats and 496 Xenopsylla fleas) in order to model the temporal dynamics of flea infestation of rats. Generalized Linear Models and Support Vector Machine classifiers were developed to model the Xenopsylla Genus Flea Index (GFI) from climatic and environmental variables. Results showed that the spatial distribution and the temporal dynamics of fleas, estimated through the GFI variations, are both strongly controlled by abiotic factors: rainfall, temperature and land cover. The models allowed linking flea abundance trends with murine typhus incidence rates. Flea infestation in rats peaked at the end of the dry season, corresponding to hot and dry conditions, before dropping sharply. This peak of maximal flea abundance preceded the annual peak of human murine typhus cases by a few weeks. Altogether, presented data raise novel questions regarding the ecology of rat fleas while developed models contribute to the design of control measures adapted to each micro region of the island with the aim of lowering the incidence of flea-borne diseases.

Sign in / Sign up

Export Citation Format

Share Document