Trends in the frequency, extent, and severity of spruce budworm outbreaks in eastern Canada

1983 ◽  
Vol 13 (4) ◽  
pp. 539-547 ◽  
Author(s):  
J. R. Blais
Keyword(s):  
20Th Century ◽  
Large Scale ◽  
Spruce Budworm ◽  
Forest Composition ◽  
Eastern Canada ◽  
Clear Cutting ◽  
The Past ◽  
Spruce Stands ◽  
History Of

The history of spruce budworm (Choristoneurafumiferana (Clem.)) outbreaks for the past 200 to 300 years, for nine regions in eastern Canada, indicates that outbreaks have occurred more frequently in the 20th century than previously. Regionally, 21 outbreaks took place in the past 80 years compared with 9 in the preceding 100 years. Earlier infestations were restricted to specific regions, but in the 20th century they have coalesced and increased in size, the outbreaks of 1910, 1940, and 1970 having covered 10, 25, and 55 million ha respectively. Reasons for the increase in frequency, extent, and severity of outbreaks appear mostly attributable to changes caused by man, in the forest ecosystem. Clear-cutting of pulpwood stands, fire protection, and use of pesticides against budworm favor fir–spruce stands, rendering the forest more prone to budworm attack. The manner and degree to which each of these practices has altered forest composition is discussed. In the future, most of these practices are expected to continue and their effects could intensify, especially in regions of recent application. Other practices, including large-scale planting of white spruce, could further increase the susceptibility of forest stands. Forest management, aimed at reducing the occurrence of extensive fir–spruce stands, has been advocated as a long-term solution to the budworm problem. The implementation of this measure at a time when man's actions result in the proliferation of fir presents a most serious challenge to forest managers.

A new paleoecological approach to reconstruct long-term history of spruce budworm outbreaks

2002 ◽  
Vol 32 (3) ◽  
pp. 428-438 ◽  
Author(s):  
Isabelle Simard ◽  
Hubert Morin ◽  
Bruno Potelle
Keyword(s):  
20Th Century ◽  
Direct Evidence ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Soil Profiles ◽  
Good Correspondence ◽  
History Of ◽  
Forest Humus

A new paleoecological indicator was used for retracing the long-term history of spruce budworm (Choristoneura fumiferana Clem.) outbreaks from forest humus. Macrofossil analyses were performed on 28 forest soil profiles (10–20 cm) collected in four balsam fir (Abies balsamea (L.) Mill.) stands located north of Lake Saint-Jean, Quebec. Direct evidence of the presence of spruce budworm was found. Few pupa fragments were present in the profiles, but the most abundant and well-preserved macrofossils collected were spruce budworm feces. The feces found were associated in part with the three outbreaks that occurred during the last century around 1914, 1952, and 1979. Good correspondence was obtained between the macrofossil results and the known dynamics of two stands, Lib20 and Lib23. However, the method failed to detect specific outbreaks in the other two stands, Lib21 and Lib24. A complementary macrofossil study was conducted on deeper humus profiles (47–70 cm) collected on two islands of Mingan Archipelago. The outbreak history of the last century was retraced, and it was established that spruce budworm was present in the Mingan Archipelago since at least 1520 years BP. The greatest numbers of spruce budworm feces were found in the first 20 cm of the humus profiles corresponding approximately to the 20th century period. Afterward, an important reduction in numbers of feces was observed. This may be attributable to lower levels of spruce budworm populations before the 20th century or the intensification of decomposition with increasing humus depth.

scholarly journals Spatiotemporal Dynamics of 20th-Century Spruce Budworm Outbreaks in Eastern Canada: Three Distinct Patterns of Outbreak Severity

2021 ◽  
Vol 8 ◽  
Author(s):  
Cassy Berguet ◽  
Maxence Martin ◽  
Dominique Arseneault ◽  
Hubert Morin
Keyword(s):  
20Th Century ◽  
Spruce Budworm ◽  
Climatic Conditions ◽  
Spatiotemporal Dynamics ◽  
Balsam Fir ◽  
White Birch ◽  
Eastern Canada ◽  
Outbreak Period ◽  
History Of ◽  
The One

Spruce budworm (SBW) outbreaks are a major disturbance in North American forests. In Quebec, Canada, the recent history of SBW outbreaks at the local scale is well-known. Studies at the Québec scale nonetheless remain rare despite the need to better understand the dynamics of SBW outbreaks at a larger scale. This study aimed to reconstruct the spatiotemporal dynamics of SBW outbreaks during the 20th century across the insect's range in southern Quebec. To this end, we sampled 83 stands throughout southern Quebec. These stands were selected according to their age and the presence of black, white, and red spruce. In fact, spruce, unlike balsam fir, survives the SBW outbreaks and can record them in these growth rings. In each stand, cores were taken from 20 spruce trees. The dendrochronological series of more than 1,600 trees were analyzed, and we identified, through the k-means grouping of stands, the spatial patterns of tree growth for the three previously documented 20th century SBW outbreaks. The outbreaks were not homogeneous across the distribution range of the insect. Two groups of stands showed early- (1905–1930) and late-century (1968–1988) outbreaks of high severity and a mid-century (1935–1965) outbreak of moderate severity. This pattern is explained mainly by the presence of the insect within the balsam fir–yellow birch and balsam fir–white birch bioclimatic domains, areas where outbreaks tend to be most severe because of the abundance of balsam fir, the main SBW host species. However, these two models differ in terms of the duration of outbreaks. A third, more northern, cluster of stands experienced lower severity outbreaks over the 20th century, a pattern explained by a lower proportion of balsam fir trees in these landscapes. Our study shows that, on the one hand, these three groups of stands are defined by outbreaks of specific duration (an outbreak period beginning when more than 20% of the trees are affected and ending when <20% of the trees are affected) and severity (in terms of percentage of affected trees), and on the other hand they are spatially distinct and subject to different climatic conditions.

scholarly journals Global climatology and trends in convective environments from ERA5 and rawinsonde data

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Mateusz Taszarek ◽  
John T. Allen ◽  
Mattia Marchio ◽  
Harold E. Brooks
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Global Climate ◽  
Convective Available Potential Energy ◽  
Global Climate Models ◽  
Convective Precipitation ◽  
The Past ◽  
The Tropics ◽  
Rawinsonde Data

AbstractGlobally, thunderstorms are responsible for a significant fraction of rainfall, and in the mid-latitudes often produce extreme weather, including large hail, tornadoes and damaging winds. Despite this importance, how the global frequency of thunderstorms and their accompanying hazards has changed over the past 4 decades remains unclear. Large-scale diagnostics applied to global climate models have suggested that the frequency of thunderstorms and their intensity is likely to increase in the future. Here, we show that according to ERA5 convective available potential energy (CAPE) and convective precipitation (CP) have decreased over the tropics and subtropics with simultaneous increases in 0–6 km wind shear (BS06). Conversely, rawinsonde observations paint a different picture across the mid-latitudes with increasing CAPE and significant decreases to BS06. Differing trends and disagreement between ERA5 and rawinsondes observed over some regions suggest that results should be interpreted with caution, especially for CAPE and CP across tropics where uncertainty is the highest and reliable long-term rawinsonde observations are missing.

scholarly journals A Survey on Edge Performance Benchmarking

2021 ◽  
Vol 54 (3) ◽  
pp. 1-33
Author(s):  
Blesson Varghese ◽  
Nan Wang ◽  
David Bermbach ◽  
Cheol-Ho Hong ◽  
Eyal De Lara ◽  
...  
Keyword(s):  
Large Scale ◽  
Future Internet ◽  
Coupled Systems ◽  
Operational Conditions ◽  
Loosely Coupled ◽  
Performance Benchmarking ◽  
The Past ◽  
Geographically Dispersed ◽  
Tightly Coupled ◽  
History Of

Edge computing is the next Internet frontier that will leverage computing resources located near users, sensors, and data stores to provide more responsive services. Therefore, it is envisioned that a large-scale, geographically dispersed, and resource-rich distributed system will emerge and play a key role in the future Internet. However, given the loosely coupled nature of such complex systems, their operational conditions are expected to change significantly over time. In this context, the performance characteristics of such systems will need to be captured rapidly, which is referred to as performance benchmarking, for application deployment, resource orchestration, and adaptive decision-making. Edge performance benchmarking is a nascent research avenue that has started gaining momentum over the past five years. This article first reviews articles published over the past three decades to trace the history of performance benchmarking from tightly coupled to loosely coupled systems. It then systematically classifies previous research to identify the system under test, techniques analyzed, and benchmark runtime in edge performance benchmarking.

How the Desert got a Past: A History of Quaternary Research in Australia’s Deserts

2014 ◽  
Vol 25 (2) ◽  
pp. 172 ◽  
Author(s):  
Mike Smith
Keyword(s):  
Climate Changes ◽  
Conceptual Space ◽  
The Past ◽  
History Of ◽  
The 1960S

This paper examines how the past of desert landscapes has been interpreted since European explorers and scientists first encountered them. It charts the research that created the conceptual space within which archaeologists and Quaternarists now work. Studies from the 1840s–1960s created the notion of a ‘Great Australian Arid Period'. The 1960s studies of Lake Mungo and the Willandra Lakes by Jim Bowler revealed the cyclical nature of palaeolakes, that changed with climate changes in the Pleistocene, and the complexity of desert pasts. SLEADS and other researchers in the 1980s used thermoluminescence techniques that showed further complexities in desert lands beyond the Willandra particularly through new studies in the Strzelecki and Simpson Dunefields, Lake Eyre, Lake Woods and Lake Gregory. Australian deserts are varied and have very different histories. Far from ‘timeless lands', they have carried detailed information about long-term climate changes on continental scales.

scholarly journals Changes in the strength and width of the Hadley Circulation since 1871

2012 ◽  
Vol 8 (4) ◽  
pp. 1169-1175 ◽  
Author(s):  
J. Liu ◽  
M. Song ◽  
Y. Hu ◽  
X. Ren
Keyword(s):  
20Th Century ◽  
Global Climate ◽  
Hadley Circulation ◽  
Recent Change ◽  
Early 20Th Century ◽  
Greenhouse Warming ◽  
Long Period ◽  
The Past ◽  
Period Oscillation

Abstract. Recent studies demonstrate that the Hadley Circulation has intensified and expanded for the past three decades, which has important implications for subtropical societies and may lead to profound changes in global climate. However, the robustness of this intensification and expansion that should be considered when interpreting long-term changes of the Hadley Circulation is still a matter of debate. It also remains largely unknown how the Hadley Circulation has evolved over longer periods. Here, we present long-term variability of the Hadley Circulation using the 20th Century Reanalysis. It shows a slight strengthening and widening of the Hadley Circulation since the late 1970s, which is not inconsistent with recent assessments. However, over centennial timescales (1871–2008), the Hadley Circulation shows a tendency towards a more intense and narrower state. More importantly, the width of the Hadley Circulation might have not yet completed a life-cycle since 1871. The strength and width of the Hadley Circulation during the late 19th to early 20th century show strong natural variability, exceeding variability that coincides with global warming in recent decades. These findings raise the question of whether the recent change in the Hadley Circulation is primarily attributed to greenhouse warming or to a long-period oscillation of the Hadley Circulation – substantially longer than that observed in previous studies.

scholarly journals Lviv as the cradle of Polish independence organizations

2021 ◽  
Vol 201 (3) ◽  
pp. 534-545
Author(s):  
Janusz Zuziak
Keyword(s):  
Twentieth Century ◽  
20Th Century ◽  
Early 20Th Century ◽  
Social Activists ◽  
The Past ◽  
Independence Movement ◽  
Political Orientations ◽  
History Of ◽  
The Right ◽  
The City

Lviv occupies a special place in the history of Poland. With its heroic history, it has earned the exceptionally honorable name of a city that has always been faithful to the homeland. SEMPER FIDELIS – always faithful. Marshal Józef Piłsudski sealed that title while decorating the city with the Order of Virtuti Militari in 1920. The past of Lviv, the always smoldering and uncompromising Polish revolutionist spirit, the climate, and the atmosphere that prevailed in it created the right conditions for making it the center of thought and independence movement in the early 20th century. In the early twentieth century, Polish independence organizations of various political orientations were established, from the ranks of which came legions of prominent Polish politicians and military and social activists.

scholarly journals Patterns of Memory in Askold Melnyczuk’s Novels as an Example of Ukrainian-American Émigré Fiction

2020 ◽  
Vol 47 (2) ◽  
pp. 125-137
Author(s):  
Marta Koval
Keyword(s):  
North America ◽  
20Th Century ◽  
European History ◽  
Family Stories ◽  
Traumatic Memories ◽  
The Past ◽  
History Of ◽  
The Dead ◽  
Definition Of

Although Ukrainian emigration to North America is not a new phenomenon, the dilemmas of memory and amnesia remain crucial in Ukrainian-American émigré fiction. The paper focuses on selected novels by Askold Melnyczuk (What is Told and Ambassador of the Dead) and analyzes how traumatic memories and family stories of the past shape the American lives of Ukrainian emigrants. The discussion of the selected Ukrainian-American émigré novels focuses on the dilemmas of remembering and forgetting in the construction of both Ukrainian and American narratives of the past. The voluntary amnesia of the Ame- rican-born Ukrainians in Melnyczuk’s novels confronts their parents’ dependence on the past and their inability to abandon it emotionally. Memories of ‘the old country’ make them, similarly to Ada Kruk, ambassadors of the dead. The expression becomes a metaphoric definition of those wrapped by their repressed, fragmentary and sometimes inaccessible memories. Crucial events of European history of the 20th century are inscribed and personalized in the older generation’s stories which their children are reluctant to hear. For them, their parents’ memories became a burden and a shame. Using the concept of transgenerational memory, the paper explores the challenges of postmemory, and eventually its failure. 

scholarly journals On Preserving the Historical Memory of the First Half of the 20th Century. Introduction to Considerations about the Past of Education

2020 ◽  
Vol 11 (2) ◽  
pp. 14-19
Author(s):  
Grzegorz Michalski
Keyword(s):  
20Th Century ◽  
Historical Memory ◽  
Interdisciplinary Studies ◽  
The Past ◽  
History Of

In the context of reflections on the breakthrough moments in the history of Poland in the first half of the 20th century, the content of the volume of the journal “Nauki o Wychowaniu. Studia Interdyscyplinarne” (Nowis. Interdisciplinary Studies) which testifies to the preservation of their historical memory, is discussed.

scholarly journals Passeism in the Musical Culture of France

2019 ◽  
Vol 16 (2) ◽  
pp. 171-182
Author(s):  
Galina A. Eremenko
Keyword(s):  
20Th Century ◽  
Cultural Influences ◽  
Young Generation ◽  
Musical Culture ◽  
Self Identity ◽  
The Past ◽  
Cultural Life ◽  
Opposite Trend ◽  
History Of ◽  
French Composers

The specialists note and highly appreciate the openness to creative dialogue with different European and regional cultures in their works about the artistic history of France. In the introductory section, the article is focused on the importance of the opposite trend, developed in the 19th — early 20th century in all spheres of art. The purpose of the new movement is “national revival”, interest in the ori­gins of the great heritage of the French masters of past epochs. The author concentrates on the peculiarities of interaction between leading composers, musicians-performers and teachers with the traditions of music professionalism of the French compo­ser school. Furthermore, she explains the main reason of “back to the past” addiction by desire to preserve the unique distinction of artistic thinking in the terms of intensive cultural influences in Italy, Germany and Russia. The article provides the facts of creative activity of the leaders of “national renewal”. There are presented some journalistic statements of the leading French composers to confirm their unanimous recognition of the actual value of national classics to the future of French culture. There is explicated the pa­norama of creative experiments (C. Franck, C. Saint-Saëns, E. Satie, impressionists and composers of the “young generation”) on reconstruction of national traditions of distant epochs. The coverage of events and display of artistic phenomena of musical and cultural life of France allowed the author to form a context to consider the problem of aesthetic and stylistic character: new understanding of the phenomenon of “artistic tradition” and “dialogue with tradition” in the epoch of modernism. The comparison of diffe­rent forms of “dialogue with the past” in the Russian culture of the beginning of the 20th century and in creative works of the leader of European retrospectivisme I.F. Stravinsky gave grounds to use the concept of “passeism” to characterize the special French type of inheritance of the “lessons” of the predecessors. Introducing the concept of “passeism” in contrast to the accepted in Russian musicology “musical neoclassicism” and giving reasons of the effectiveness of its application, the author seeks to identify the idea of preser­ving soil foundations of tradition as a way of national self-identity (prosody, rhetoric, form) pertaining to the French composer school.

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