Defoliation of tamarack by outbreak populations of larch sawfly in subarctic Quebec: measuring the impact on tree growth

1993 ◽  
Vol 23 (7) ◽  
pp. 1444-1452 ◽  
Author(s):  
Isabelle Tailleux ◽  
Conrad Cloutier
Keyword(s):  
Tree Growth ◽  
Large Scale ◽  
Tree Mortality ◽  
Sampling Site ◽  
Climatic Conditions ◽  
Soil Conditions ◽  
Outbreak Period ◽  
Larch Sawfly ◽  
Foliage Development ◽  
The Impact

In conjunction with other major perturbations, outbreaks of specialist insect defoliators could play a key role in the long-term evolution of northern forest communities. Sawfly oviposition marks up to 20 years old in shoots of tamarack, Larixlaricina (Du Roi) K. Koch, provide a direct record of a large-scale epidemic cycle of the larch sawfly, Pristiphoraerichsonii (Htg.), during the 1980s in the Grande Rivière de la Baleine region, northern Quebec. Because no significant tree mortality was noted in the years following peak defoliator populations in 1985–1986, a study was undertaken to determine whether insect population changes during the outbreak period were correlated with growth changes under various climatic and soil conditions in three coastal sites and one continental sampling site. The fluctuations with time in the density of oviposition marks on trees indicated that the epidemic cycle was synchronous at all sites. However, the defoliator's density was significantly higher at the inland site, located 150 km from Hudson Bay, than at the coastal sites, where climatic conditions may be less favorable to insect activity and survival. No significant effects on tree growth were detected at the coastal sites, whereas larch from the inland site recorded a significant reduction in radial growth in 1984, the 1st year of outbreak conditions. Larch from this site also showed significant effects on foliage development after 4 years of defoliation (1988), when a virtual stop on elongative growth became apparent. Larch trees reproduced actively during the outbreak, with peak reproductive effort in 1984 and 1987 correlating with lows in elongative growth. Delayed or minimal effects of this outbreak characterized by the presence of hundreds of sawfly colonies per tree and defoliation levels comparable to those observed in the boreal forest during similar outbreaks indicate that subarctic larch may be highly tolerant to prolonged defoliation by the larch sawfly.

An experiment in the control of the ground water-level in a fen peat soil

1951 ◽  
Vol 41 (1-2) ◽  
pp. 149-162 ◽  
Author(s):  
H. H. Nicholson ◽  
G. Alderman ◽  
D. H. Firth
Keyword(s):  
Ground Water ◽  
Water Level ◽  
Large Scale ◽  
Field Experiments ◽  
Peat Soil ◽  
Climatic Conditions ◽  
Ground Water Level ◽  
Effective Control ◽  
Soil Conditions ◽  
Local Soil

1. The methods of investigation of the effect of ground water-level on crop growth, together with tho field installations in use, are discussed.2. Direct field experiments are handicapped by the difficulties of achieving close control on a sufficiently large scale, due to considerable variations of surface level and depth of peat within individual fields and to rapid fluctuations in rainfall and evaporation. Many recorded experiments are associated with climatic conditions of substantial precipitation during the growing season.3. Seasonal fluctuations of ground water-level in Fen peat soils in England, in natural and agricultural conditions, are described.4. The local soil conditions are outlined and the implications of profile variations are discussed.5. The effective control of ground water-level on a field scale requires deep and commodious ditches and frequent large underdrains to ensure the movement of water underground with sufficient freedom to give rapid compensatory adjustment for marked disturbances of ground water-level following the incidence of heavy rain or excessive evaporation.6. A working installation for a field experiment in ordinary farming conditions is described and the measure of control attained is indicated.

Impact of Storage Integrated Solar Photovoltaics (PV) Power System on Utility Peak Loads

2011 ◽  
Author(s):  
K. Agyenim-Boateng ◽  
R. F. Boehm
Keyword(s):  
Large Scale ◽  
Peak Load ◽  
Average Energy ◽  
Transient Behavior ◽  
Climatic Conditions ◽  
Photovoltaic System ◽  
Solar Pv ◽  
Pv System ◽  
Grid Load ◽  
The Impact

The promise of large-scale use of renewables such as wind and solar for supplying electrical power is tempered by the sources’ transient behavior and the impact this would have on the operation of the grid. One way of addressing this is through the use of supplemental energy storage. While the technology for the latter has not been proven on a large scale or to be economical at the present time, some assessments of what magnitude is required can be made. In performing this work we have used NREL’s Solar Advisor Model (SAM 2010) with TMY3 solar data to estimate the photovoltaic system power generation. Climatic conditions close to load centers were chosen for the simulations. Then the PV output for varying sizes of arrays were examined and the impact of varying amounts of storage investigated. The storage was characterized by maximum limiting energy and power capacities based on annual hourly peak load, as well as its charging and discharging efficiencies. The simulations were performed using hourly time steps with energy withdrawn from, or input to, storage only after considering base generation and the PV system output in serving the grid load. In this work, we examined the load matching capability of solar PV generation (orientated for maximum summer output) for a sample Southwestern US utility grid load of 2008. Specifically we evaluated the daily and seasonal peak load shifting with employing varying storage capacities. The annual average energy penetration based on the usable solar PV output is also examined under these conditions and at different levels of system flexibility.

scholarly journals The Methods of Locating Areas Exposed to Wind Erosion in the South Moravia Region

2015 ◽  
Vol 63 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Jana Podhrázská ◽  
Josef Kučera ◽  
Hana Středová
Keyword(s):  
Wind Erosion ◽  
Climatic Conditions ◽  
Soil Conditions ◽  
Atmospheric Conditions ◽  
The South ◽  
Spatial Function ◽  
Forest Belts ◽  
Protective Forest ◽  
South Moravia ◽  
The Impact

The conditions for the development of wind erosion are determined by the soil and climatic conditions as well as by the presence or absence of wind barriers. It is because of its climatic and soil conditions that the territory of the South Moravia Region has been affected by erosion for centuries. Combined with the atmospheric conditions, the dry and warm climate enables the development of aeolian processes both in light, drying soils and – under certain climatic conditions – in heavy, clay-loam soils. Soil erosion exposure maps have been prepared in order to identify the territories which are potentially exposed to wind erosion in terms of the soil and climatic conditions. Six exposure categories have been applied to the soils. However, the impact of permanent vegetation barriers – line elements – must be considered in order to identify the most exposed areas. Protective forest belts were planted in the 1950s to counter the effects of wind erosion and they are included in the database of the Institute for Economic Forest Management. The network of these wind barriers and the heath condition of the individual elements are often unsatisfactory because of poor maintenance. The purpose of the study was to evaluate the spatial function of the network of protective forest belts using the map of the potential exposure of soil in the Region of South Moravia. The method used to evaluate the spatial function of the windbreaks presented in the study using GIS instruments.

scholarly journals Status quo of pastures in Uzbekistan and their effective utilization

2021 ◽  
Vol 937 (3) ◽  
pp. 032069
Author(s):  
M I Ruzmetov
Keyword(s):  
Climate Change ◽  
Crop Productivity ◽  
Climatic Conditions ◽  
Soil Conditions ◽  
Effective Utilization ◽  
Gis Technologies ◽  
Current State ◽  
The Earth ◽  
Pasture Degradation ◽  
The Impact

Abstract The Global research to assess the impact of climate change on soil-climatic conditions of arid lands has resulted in the following scientific findings: pasture degradation due to inefficient use of available resources; improved technologies for the condition of pasture soils and their restoration and the use of GIS monitoring; soil conditions, desertification factors and degradation processes of anthropogenesis in pasture conditions; developments for remote sensing of the Earth to determine the current state of pastures and the use of GIS technologies; and, improved technologies for adapting to climate change and combating soil degradation. Measures have been developed to restore biodiversity, increase crop productivity, and increase the fertility of these soils. This article describes the relevance of pasture land use around the world and the effectiveness of the use of a variety of water-saving technologies (Water-box) in the foothills and desert pastures.

Soil Carbon Dynamics and Atmospheric Signals in Stalagmite Radiocarbon at Sofular Cave, Turkey

2021 ◽  
Author(s):  
Steffen Therre ◽  
Jens Fohlmeister ◽  
Dominik Fleitmann ◽  
Ronny Friedrich ◽  
Andrea Schröder-Ritzrau ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Growth Period ◽  
Climatic Conditions ◽  
Series Data ◽  
Temperate Climate ◽  
Soil Conditions ◽  
Radiocarbon Age ◽  
Soil Activity ◽  
The Impact ◽  
Radiocarbon Calibration

<p><span>The climatic controls of stalagmite radiocarbon remain one focus of modern paleoclimatology due to recent efforts and achievements in radiocarbon calibration. The Hulu cave radiocarbon record (Cheng et al., 2018) has proven the potential of stalagmites from temperate climate zones for atmospheric radiocarbon reconstruction. However, a constant dead carbon fraction (DCF) in stalagmites over long periods of time is rather exceptional. In our study, a high-resolution radiocarbon record (N>100) of a U-Series dated stalagmite from Sofular Cave, Northern Turkey, with elemental Mg/Ca ratio data is presented. From 14 to 10 kyr BP, the radiocarbon signal reveals changing climatic conditions throughout Termination I with warm periods affiliated with increased soil activity and lower DCF. We observe unstable soil conditions for the period before 14 kyr BP where DCF is strongly variable between a lower threshold of ca. 5% and an upper limit of 25%. The combination of stable isotopes, element ratios, radiocarbon and U-series data allows a multi-proxy analysis of the impact of fast climate changes like D/O events on the incorporation of radiocarbon into stalagmites. Between 15 and 27 kyr BP, hydrological changes and soil carbon cycling have a large impact on limestone dissolution systematics which is reflected in fast changing DCF on sub-centennial time scales. Although the reconstruction of atmospheric radiocarbon variability is not possible for the entire growth period, the stalagmite closely reproduces the increased atmospheric radiocarbon concentration at ca. 40 kyr BP during the Laschamp geomagnetic reversal, which has been implemented into radiocarbon calibration curves with the publication of IntCal20 (Reimer et al. 2020). Our record provides new insights in the climatic influence on stalagmite radiocarbon and as to how precision and accuracy of calibration can benefit from comprehensive multi-proxy stalagmite records.</span></p><p><span>References</span></p><p><span>Cheng, H., Lawrence Edwards, R., Southon, J., et al.: Atmospheric 14C/12C changes during the last glacial period from Hulu cave, Science, 362(6420), 1293–1297, doi:10.1126/science.aau0747, 2018.</span></p><p><span>Reimer, P. J., Austin, W. E. N., Bard, E., Bayliss, A., et al.: The IntCal20 Northern Hemisphere Radiocarbon Age Calibration Curve (0–55 cal kBP), Radiocarbon, 62(4), 725-757. doi:10.1017/RDC.2020.41</span></p>

Daily rainfall above 75mm is a major trigger to landslides in the Muhunguzi, western Burundi

2020 ◽  
Author(s):  
Clairia Kankurize ◽  
Gervais Rufyikiri ◽  
Bruno Delvaux
Keyword(s):  
Management Practices ◽  
Local Population ◽  
Daily Rainfall ◽  
Climatic Conditions ◽  
Anthropogenic Factors ◽  
Soil Conditions ◽  
Waterborne Diseases ◽  
East African ◽  
African Rift ◽  
The Impact

<p>Located in the East African Rift Valley, western Burundi is often threatened by landslides during the rainy season. Damage can be seen both in the mountains, the sites of the landslides, and in the plain where sediments are deposited: environmental degradation, loss upstream and downstream of cultivated land, destruction of infrastructures, loss of life, waterborne diseases, floods of streams laden with sludge and stones torn off during landslides... The magnitude of these shifts justifies the need for studies to understand the factors that cause this part of Burundi to be vulnerable to landslides.</p><p>Here we highlight the relationship between the environmental context and the process of landslides in this region. To analyze the impact of geomorphological, geological, soil and climatic conditions as well as anthropogenic factors, we carried out an inventory of landslides in the Muhunguzi watershed, a survey of the local population and an analysis of rainfall over the period 1935-2014.</p><p>Of 7 Muhunguzi sub-watersheds with a total area of 21.2 km<sup>2</sup>, 43 landslides were identified, 29 of which were on a single sub-watershed. Most landslides were shallow. Geomorphology was characterized by steep escarpments interspersed with valleys. The landslides were located on the lower slopes and most affected the rivers. The lithology was dominated by shale inclined parallel to the slope. Landslides were located on rocky, black or red soils, identified as Nitisols. The majority of landslides occurred on cultivated fields. Daily precipitations ranging between 75mm and 100mm with a return period of 5.3 years are strongly correlated to shallow landslides in the studied area. Such intense daily rain thus appears here as a major trigger to these landslides. In addition, relief, geological and soil conditions are predisposing factors while population density and the resulting land pressure worsen land instability.</p><p>We conclude that further studies are needed to understand the impact of soil processes and human activity in order to identify adequate management practices preventing landslides in Muhunguzi area.</p>

scholarly journals Tree growth is more limited by drought in rear-edge forests most of the times

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
J. Julio Camarero ◽  
Antonio Gazol ◽  
Gabriel Sangüesa-Barreda ◽  
Marta Vergarechea ◽  
Raquel Alfaro-Sánchez ◽  
...  
Keyword(s):  
Tree Growth ◽  
Tree Species ◽  
Large Scale ◽  
Abies Alba ◽  
Growth Patterns ◽  
Widespread Species ◽  
Growth Variability ◽  
Rear Edge ◽  
Species Vulnerability ◽  
The Impact

Abstract Background Equatorward, rear-edge tree populations are natural monitors to estimate species vulnerability to climate change. According to biogeographical theory, exposition to drought events increases with increasing aridity towards the equator and the growth of southern tree populations will be more vulnerable to drought than in central populations. However, the ecological and biogeographical margins can mismatch due to the impact of ecological factors (topography, soils) or tree-species acclimation that can blur large-scale geographical imprints in trees responses to drought making northern populations more drought limited. Methods We tested these ideas in six tree species, three angiosperms (Fagus sylvatica, Quercus robur, Quercus petraea) and three gymnosperms (Abies alba, Pinus sylvestris and Pinus uncinata) by comparing rear-edge tree populations subjected to different degrees of aridity. We used dendrochronology to compare the radial-growth patterns of these species in northern, intermediate, and southern tree populations at the continental rear edge. Results and conclusions We found marked variations in growth variability between species with coherent patterns of stronger drought signals in the tree-ring series of the southern populations of F. sylvatica, P. sylvestris, and A. alba. This was also observed in species from cool-wet sites (P. uncinata and Q. robur), despite their limited responsiveness to drought. However, in the case of Q. petraea the intermediate population showed the strongest relationship to drought. For drought-sensitive species as F. sylvatica and P. sylvestris, southern populations presented more variable growth which was enhanced by cool-wet conditions from late spring to summer. We found a trend of enhanced vulnerability to drought in these two species. The response of tree growth to drought has a marked biogeographical component characterized by increased drought sensitivity in southern populations even within the species distribution rear edge. Nevertheless, the relationship between tree growth and drought varied between species suggesting that biogeographical and ecological limits do not always overlap as in the case of Q. petraea. In widespread species showing enhanced vulnerability to drought, as F. sylvatica and P. sylvestris, increased vulnerability to climate warming in their rear edges is forecasted. Therefore, we encourage the monitoring and conservation of such marginal tree populations.

scholarly journals The impact of Hurricane Michael on longleaf pine habitats in Florida

2019 ◽  
Author(s):  
Nicole E. Zampieri ◽  
Stephanie Pau ◽  
Daniel K. Okamoto
Keyword(s):  
Climate Change ◽  
Large Scale ◽  
Tree Mortality ◽  
Size Structure ◽  
Longleaf Pine ◽  
Pinus Palustris ◽  
Climate Change Impacts ◽  
The North ◽  
Integral Role ◽  
The Impact

AbstractThe longleaf pine (Pinus palustris) ecosystem of the North American Coastal Plain (NACP) is a global biodiversity hotspot. Disturbances such as tropical storms play an integral role in ecosystem maintenance in these systems. However, altered disturbance regimes as a result of climate change may be outside the historical threshold of tolerance. Hurricane Michael impacted the Florida panhandle as a Category 5 storm on October 10th, 2018. In this study, we estimate the extent of Florida longleaf habitat that was directly impacted by Hurricane Michael. We then quantify the impact of Hurricane Michael on tree density and size structure using a Before-After study design at four sites (two wet flatwood and two upland pine communities). Finally, we identify the most common type of tree damage at each site and community type. We found that 39% of the total remaining extent of longleaf pine habitat was affected by the storm in Florida alone. Tree mortality ranged from 1.3% at the site furthest from the storm center to 88.7% at the site closest. Most of this mortality was in mature sized trees (92% mortality), upon which much of the biodiversity in this habitat depends. As the frequency and intensity of extreme events increases, management plans that mitigate for climate change impacts need to account for large-scale stochastic mortality events in order to effectively preserve critical habitats.

scholarly journals Impact of Orientation on the Thermal Performances in Vernacular Buildings in Hot Arid Climate

2019 ◽  
Vol 9 (2) ◽  
pp. 4840-4847
Keyword(s):  
Thermal Comfort ◽  
Large Scale ◽  
Cooling System ◽  
Vernacular Architecture ◽  
Climatic Conditions ◽  
Point Of View ◽  
Occupant Comfort ◽  
Vernacular Buildings ◽  
Scale Integration ◽  
The Impact

Morocco faces enormous climatic constraints. A large part of the national territory has a hot and dry climate, hence the importance of the climate aspect in the choice of an energy saving strategy. The use of reinterpreted, decontextualized, totally or partially vernacular architectural techniques and/or forms is visible at different levels in the Maghreb countries. The large-scale integration of this aspect seems to be ignored by the designers. The objective of this research is to evaluate the impact of the building orientation and vernacular architecture towards the occupant comfort, in order to meet its energy and comfort needs at a lower cost on one hand, and on the other hand, to design more efficient collective buildings from a thermal and energy point of view. The proposed methodology allows examining the thermal performances of a traditional building under the climatic conditions of the city of Rissani in order to naturally control comfort summer and winter, in addition to ensure a good thermal comfort without using any heating or cooling system. Finally, the simulations carried out lead to the identification of the optimal orientation that demonstrates an effective reduction in indoor temperatures and a decrease in the large daily fluctuations in these temperatures. The research focuses on the influence of the orientation of a building's facades in relation to the solar radiation and on providing the necessary thermal comfort.

scholarly journals Waldzustand in der Schweiz: Erfassung, Entwicklung und Einflussfaktoren

2012 ◽  
Vol 163 (9) ◽  
pp. 331-342
Author(s):  
Matthias Dobbertin ◽  
Christian Hug ◽  
Lorenz Walthert
Keyword(s):  
Air Pollution ◽  
Nitrogen Deposition ◽  
Tree Growth ◽  
Large Scale ◽  
Climatic Factors ◽  
Climatic Conditions ◽  
Crown Condition ◽  
Forest Condition ◽  
Crown Defoliation ◽  
Negative Effect

Forest condition in Switzerland: assessment, development and influencing factors In the early 1980s it was feared that air pollution would cause a widespread forest decline and a reduction in forest productivity. In Switzerland as in most European countries crown defoliation and foliage discoloration were selected as the most important indicators of forest condition. The Sanasilva inventory on a systematic network of plots showed an increase in the proportion of trees with high defoliation until 1995. Since then no trend has been detected. However, large annual fluctuations were often observed following years with large-scale climatic events, such as the storms Vivian and Lothar and the heat summer of 2003. Although highly variable, neither mortality nor removal rates have shown any time trend since 1985. The annual differences in crown defoliation, mortality and tree growth are mainly related to climatic factors. In addition to the climatic conditions, nutrient availability, soil water holding capacity and to a lesser extent air pollution determine the degree of crown defoliation at a given site and for a given species. Although several studies have found a negative effect of nitrogen deposition or ozone concentrations on tree foliation, others have shown that up to now nitrogen deposition has increased tree growth on nitrogen-limited sites. It can thus be concluded that presently air pollution does not pose a direct threat to tree conditions in Switzerland. However, the assessment of crown condition alone is not a suitable tool to detect the effects of air pollution on forests. This requires more detailed measurements on long-term research sites. However, as crown condition is strongly affected by site conditions and climate, it should be further monitored, particularly with regard to the predicted climate change.

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