scholarly journals Temporal Dynamics of Root Reinforcement in European Spruce Forests

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 815
Author(s):  
Gianluca Flepp ◽  
Roger Robyr ◽  
Roberto Scotti ◽  
Filippo Giadrossich ◽  
Marco Conedera ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
National Forest Inventory ◽  
Root Reinforcement ◽  
Local Conditions ◽  
Spruce Forests ◽  
Forest Ecosystem Services ◽  
Combining Data ◽  
Spruce Stands ◽  
Recovery Dynamics

The quantification of post-disturbance root reinforcement (RR) recovery dynamics is of paramount importance for the optimisation of forest ecosystem services and natural hazards risk management in mountain regions. In this work we analyse the long-term root reinforcement dynamic of spruce forests combining data of the Swiss National Forest Inventory with data on root distribution and root mechanical properties. The results show that root reinforcement recovery depends primarily on stand altitude and slope inclination. The maximum root reinforcement recovery rate is reached at circa 100 years. RR increases continuously with different rates for stand ages over 200 years. These results shows that RR in spruce stands varies considerably depending on the local conditions and that its recovery after disturbances requires decades. The new method applied in this study allowed for the first time to quantify the long term dynamics of RR in spruce stands supporting new quantitative approaches for the analysis of shallow landslides disposition in different disturbance regimes of forests.

scholarly journals Changes in the mycorrhizal status of some mountain spruce forests

2008 ◽  
Vol 53 (Special Issue) ◽  
pp. 82-88
Author(s):  
V. Pešková
Keyword(s):  
Air Pollution ◽  
Mycorrhizal Fungi ◽  
Mycorrhizal Symbiosis ◽  
Clear Trend ◽  
Apparent Increase ◽  
Spruce Forests ◽  
Mycorrhizal Status ◽  
Spruce Stands ◽  
Pollution Impact

In the present study, the defoliation status of spruce stands is related to mycorrhizal conditions and presence of mycorrhizal macromycetes fungi in two localities at the highest sites of the Krkonoše Mts. In the long-term view, the defoliation and the diversity of mycorrhizal fungi have improved but the number of active as well as nonactive mycorrhizae has decreased while their ratio has not changed. Statistically significant is the correlation between the total number of mycorrhizae and pH. The results within last years of observations as well as in comparison to the conditions in the last decade show that mountain spruce stands growing at non-exposed sites are tolerant to a degradation of mycorrhizal conditions resulting from the long-term air pollution impact. The studied parameters of mycorrhizal symbiosis have not shown a clear trend; their results however indicate the stabilized mycorrhizal state. Positive changes can be seen in the total increase of macromycetes diversity as well as in the apparent increase of percentage of macromycetes in the studied localities, which correlates to the moderately improving defoliation.

scholarly journals Dynamics of protective spruce stands in Moscow region

2021 ◽  
Vol 25 (4) ◽  
pp. 27-33
Author(s):  
S.A. Korotkov ◽  
◽  
Yu. I. Drobyshev ◽  
◽  
Keyword(s):  
Climate Changes ◽  
Insect Pests ◽  
Moscow Region ◽  
Coniferous Forests ◽  
Mixed Stands ◽  
Small Areas ◽  
Spruce Forests ◽  
Spruce Stands ◽  
New Generation

The results of dynamic processes occurring in recent decades in the forests of the Moscow region cxontaining spruce and caused by both climate changes and increasing anthropogenic influence are presented. It is demonstrated that the spruce stands in modern conditions are unstable to droughts and outbreaks of insect pests, and in the future they will also be dynamically unstable and tend to decay. The situation is even more complicated due to the ban on continuous logging in the protective forests of the Moscow region and the widespread distribution of monocultures here, which, moreover, continue to be created even now. It is established that the structure of stands by age and diameter is largely determined by the density of the stand and the mixing of species, and is most aligned in pure high-field forests, and the optimal structure in diameter is formed with a proportion of spruce trees of 3–7 units. As a result of long-term observations on permanent sample areas in «Losiny Ostrov», it was revealed that with the natural development of forest communities, the composition of new forest generations is extremely rarely close to the composition of the first tier. In most cases, the development goes towards broad-leaved forests with a predominance of linden. The same tendency to replace coniferous forests with linden forests is shown for plantings where the spruce part of the stand was lost due to the bark beetle. Both on the site of the decayed spruce forests and under the canopy of the preserved ones, a new generation of forest is formed, represented by hardwoods with a small or single participation of spruce. It is recommended to form mixed stands in the spruce forests of the Moscow region with a proportion of spruce of 30…50 %, while a higher proportion of spruce may be acceptable only in small areas (1–2 ha). At the same time, the mass creation of monodominant spruce crops should be avoided.

Economic conditions and perceptions of immigrants as an economic threat in Europe: Temporal dynamics and mediating processes

2021 ◽  
pp. 002071522199352
Author(s):  
Boris Heizmann ◽  
Nora Huth
Keyword(s):  
Temporal Dynamics ◽  
European Social Survey ◽  
Primary Objective ◽  
Conflict Theory ◽  
Economic Conditions ◽  
Political Climate ◽  
Short Term ◽  
Economic Threat ◽  
Party Positions

This article addresses the extent to which economic downturns influence the perception of immigrants as an economic threat and through which channels this occurs. Our primary objective is an investigation of the specific mechanisms that connect economic conditions to the perception of immigrants as a threat. We therefore also contribute to theoretical discussions based on group threat and realistic group conflict theory by exposing the dominant source of competition relevant to these relationships. Furthermore, we investigate whether people react more sensitive to short-term economic dynamics within countries than to the long-term economic circumstances. Our database comprises all waves of the European Social Survey from 2002 to 2017. The macro-economic indicators we use include GDP per capita, unemployment, and national debt levels, covering the most salient economic dimensions. We furthermore control for the country’s migration situation and aggregate party positions toward cultural diversity. Our results show that the dynamic short-term developments of the economy and migration within countries are of greater relevance for perceived immigrant threat than the long-term situation. In contrast, the long-term political climate appears to be more important than short-term changes in the aggregate party positions. Further mediation analyses show that objective economic conditions influence anti-immigrant attitudes primarily through individual perceptions of the country’s economic performance and that unemployment rates are of primary importance.

scholarly journals Global soil moisture data derived through machine learning trained with in-situ measurements

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Sungmin O. ◽  
Rene Orth
Keyword(s):  
Machine Learning ◽  
Soil Moisture ◽  
Large Scale ◽  
Short Term Memory ◽  
Temporal Dynamics ◽  
Soil Moisture Data ◽  
Wide Range ◽  
Global Soil

AbstractWhile soil moisture information is essential for a wide range of hydrologic and climate applications, spatially-continuous soil moisture data is only available from satellite observations or model simulations. Here we present a global, long-term dataset of soil moisture derived through machine learning trained with in-situ measurements, SoMo.ml. We train a Long Short-Term Memory (LSTM) model to extrapolate daily soil moisture dynamics in space and in time, based on in-situ data collected from more than 1,000 stations across the globe. SoMo.ml provides multi-layer soil moisture data (0–10 cm, 10–30 cm, and 30–50 cm) at 0.25° spatial and daily temporal resolution over the period 2000–2019. The performance of the resulting dataset is evaluated through cross validation and inter-comparison with existing soil moisture datasets. SoMo.ml performs especially well in terms of temporal dynamics, making it particularly useful for applications requiring time-varying soil moisture, such as anomaly detection and memory analyses. SoMo.ml complements the existing suite of modelled and satellite-based datasets given its distinct derivation, to support large-scale hydrological, meteorological, and ecological analyses.

scholarly journals Acute symptoms of mild to moderate COVID-19 are highly heterogeneous across individuals and over time

2021 ◽  
Author(s):  
Thomas L Rodebaugh ◽  
Madelyn R Frumkin ◽  
Angela M Reiersen ◽  
Eric J Lenze ◽  
Michael S Avidan ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Survey Methods ◽  
Clinical Care ◽  
Clinical Deterioration ◽  
Symptom Profiles ◽  
Fluctuating Course ◽  
The Common ◽  
Symptom Changes ◽  
Over Time

Abstract Background The symptoms of COVID-19 appear to be heterogenous, and the typical course of these symptoms is unknown. Our objectives were to characterize the common trajectories of COVID-19 symptoms and assess how symptom course predicts other symptom changes as well as clinical deterioration. Methods 162 participants with acute COVID-19 responded to surveys up to 31 times for up to 17 days. Several statistical methods were used to characterize the temporal dynamics of these symptoms. Because nine participants showed clinical deterioration, we explored whether these participants showed any differences in symptom profiles. Results Trajectories varied greatly between individuals, with many having persistently severe symptoms or developing new symptoms several days after being diagnosed. A typical trajectory was for a symptom to improve at a decremental rate, with most symptoms still persisting to some degree at the end of the reporting period. The pattern of symptoms over time suggested a fluctuating course for many patients. Participants who showed clinical deterioration were more likely to present with higher reports of severity of cough and diarrhea. Conclusion The course of symptoms during the initial weeks of COVID-19 is highly heterogeneous and is neither predictable nor easily characterized using typical survey methods. This has implications for clinical care and early-treatment clinical trials. Additional research is needed to determine whether the decelerating improvement pattern seen in our data is related to the phenomenon of patients reporting long-term symptoms, and whether higher symptoms of diarrhea in early illness presages deterioration.

scholarly journals Imitated Whole Tree Harvesting Show Negligible Effect on Economic Value of Spruce Stands

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 841
Author(s):  
Iveta Desaine ◽  
Annija Kārkliņa ◽  
Roberts Matisons ◽  
Anna Pastare ◽  
Andis Adamovičs ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Economic Value ◽  
Forest Types ◽  
Spruce Stands ◽  
The Difference ◽  
Growing Conditions ◽  
Whole Tree Harvesting ◽  
Whole Tree ◽  
Tree Harvesting

The increased removal of forest-derived biomass with whole-tree harvesting (WTH) has raised concerns about the long-term productivity and sustainability of forest ecosystems. If true, this effect needs to be factored in the assessment of long-term feasibility to implement such a drastic forest management measure. Therefore, the economic performance of five experimental plantations in three different forest types, where in 1971 simulated WTH event occurred, was compared with pure, planted and conventionally managed (CH) Norway spruce stands of similar age and growing conditions. Potential incomes of CH and WTH stands were based on timber prices for period 2014–2020. However, regarding the economics of root and stump biomass utilization, they were not included in the estimates. In any given price level, the difference of internal rate of return between the forest types and selected managements were from 2.5% to 6.2%. Therefore, Norway spruce stands demonstrate good potential of independence regardless of stump removal at the previous rotation.

scholarly journals MEG signatures of long-term effects of agreement and disagreement with the majority

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Gorin ◽  
V. Klucharev ◽  
A. Ossadtchi ◽  
I. Zubarev ◽  
V. Moiseeva ◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
Social Influence ◽  
Temporal Dynamics ◽  
Peer Group ◽  
Long Term Effects ◽  
Learning Mechanisms ◽  
Source Imaging ◽  
The Face ◽  
First Session

AbstractPeople often change their beliefs by succumbing to an opinion of others. Such changes are often referred to as effects of social influence. While some previous studies have focused on the reinforcement learning mechanisms of social influence or on its internalization, others have reported evidence of changes in sensory processing evoked by social influence of peer groups. In this study, we used magnetoencephalographic (MEG) source imaging to further investigate the long-term effects of agreement and disagreement with the peer group. The study was composed of two sessions. During the first session, participants rated the trustworthiness of faces and subsequently learned group rating of each face. In the first session, a neural marker of an immediate mismatch between individual and group opinions was found in the posterior cingulate cortex, an area involved in conflict-monitoring and reinforcement learning. To identify the neural correlates of the long-lasting effect of the group opinion, we analysed MEG activity while participants rated faces during the second session. We found MEG traces of past disagreement or agreement with the peers at the parietal cortices 230 ms after the face onset. The neural activity of the superior parietal lobule, intraparietal sulcus, and precuneus was significantly stronger when the participant’s rating had previously differed from the ratings of the peers. The early MEG correlates of disagreement with the majority were followed by activity in the orbitofrontal cortex 320 ms after the face onset. Altogether, the results reveal the temporal dynamics of the neural mechanism of long-term effects of disagreement with the peer group: early signatures of modified face processing were followed by later markers of long-term social influence on the valuation process at the ventromedial prefrontal cortex.

scholarly journals Increasing frequency of low summer precipitation synchronizes dynamics and compromises metapopulation stability in the Glanville fritillary butterfly

2015 ◽  
Vol 282 (1806) ◽  
pp. 20150173 ◽  
Author(s):  
Ayco J. M. Tack ◽  
Tommi Mononen ◽  
Ilkka Hanski
Keyword(s):  
Population Dynamics ◽  
Population Change ◽  
Temporal Dynamics ◽  
Summer Precipitation ◽  
Life History Stage ◽  
General Effect ◽  
Spatial Synchrony ◽  
Glanville Fritillary Butterfly ◽  
Spatio Temporal

Climate change is known to shift species' geographical ranges, phenologies and abundances, but less is known about other population dynamic consequences. Here, we analyse spatio-temporal dynamics of the Glanville fritillary butterfly ( Melitaea cinxia ) in a network of 4000 dry meadows during 21 years. The results demonstrate two strong, related patterns: the amplitude of year-to-year fluctuations in the size of the metapopulation as a whole has increased, though there is no long-term trend in average abundance; and there is a highly significant increase in the level of spatial synchrony in population dynamics. The increased synchrony cannot be explained by increasing within-year spatial correlation in precipitation, the key environmental driver of population change, or in per capita growth rate. On the other hand, the frequency of drought during a critical life-history stage (early larval instars) has increased over the years, which is sufficient to explain the increasing amplitude and the expanding spatial synchrony in metapopulation dynamics. Increased spatial synchrony has the general effect of reducing long-term metapopulation viability even if there is no change in average metapopulation size. This study demonstrates how temporal changes in weather conditions can lead to striking changes in spatio-temporal population dynamics.

Estimating long-term tree mortality rate time series by combining data from periodic inventories and harvest reports in a Bayesian state-space model

2013 ◽  
Vol 292 ◽  
pp. 64-74 ◽  
Author(s):  
Katalin Csilléry ◽  
Maëlle Seignobosc ◽  
Valentine Lafond ◽  
Georges Kunstler ◽  
Benoît Courbaud
Keyword(s):  
Time Series ◽  
Mortality Rate ◽  
State Space ◽  
Tree Mortality ◽  
State Space Model ◽  
Space Model ◽  
Combining Data

scholarly journals The Observatorio Astronómico Nacional - Tonantzintla: Site Evaluation

2009 ◽  
Vol 5 (S260) ◽  
Author(s):  
H.M. Hernández-Toledo ◽  
L.A. Martínez-Vázquez ◽  
A. Pani-Cielo
Keyword(s):  
Ccd Photometry ◽  
Local Conditions ◽  
Astronomy Education ◽  
Site Evaluation ◽  
New Instrumentation ◽  
Sky Conditions ◽  
Alternative Solutions ◽  
Term Monitoring

AbstractThe objective of this contribution is to present some results of an evaluation on the local conditions at the site that were considered in order to propose that the Observatorio Astronómico Nacional, Tonantzintla, (OAN-Tonantzintla) become a National Facility for Astronomy Education. The evaluation included a quantitative diagnostic (CCD photometry) on the quality of the local sky. The attributes of the 1-m telescope, the current instrumentation and a well planned upgrading that includes new instrumentation is considered at the basis for a successful transition maintaining the attractiveness of the site for astronomy education. A 3-year upgrading program actually in progress at UNAM is providing funding for that purpose. Physics and astronomy programs at college and graduated levels at UNAM will benefit from this, yielding clear connections among astronomy researchers and educators and students at various levels. Although the OAN-Tonantzintla faces the danger of deteriorating its sky conditions, we are maintaining awareness of the night sky characteristics in long-term monitoring campaigns and encouraging the local authorities to find alternative solutions to this problem.

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