scholarly journals Jahrringforschung und Klimawandel in den borealen Wäldern | Annual ring research and climate change in boreal forests

2002 ◽  
Vol 153 (1) ◽  
pp. 29-32 ◽  
Author(s):  
Fritz H. Schweingruber
Keyword(s):  
Climate Change ◽  
Boreal Forests ◽  
Annual Ring ◽  
Ring Width ◽  
Volcanic Eruptions ◽  
Boreal Zone ◽  
Ring Network ◽  
The Past ◽  
Summer Temperatures ◽  
Northern Hemispheric

For a climatological interpretation of annual-ring sequences we used the northern hemispheric tree-ring network collected by the WSL for the boreal zone and subalpine areas. Ring width and maximum densities point to climatological events of short duration triggered by volcanic eruptions, as well as decennial and centennial changes of summer temperatures over the past 8000 years. The current warm period roughly corresponds to that which occurred around AD 1000.

An introduction to Canada’s boreal zone: ecosystem processes, health, sustainability, and environmental issues

2013 ◽  
Vol 21 (4) ◽  
pp. 207-226 ◽  
Author(s):  
J.P. Brandt ◽  
M.D. Flannigan ◽  
D.G. Maynard ◽  
I.D. Thompson ◽  
W.J.A. Volney
Keyword(s):  
Climate Change ◽  
Boreal Forests ◽  
Native Species ◽  
Natural Disturbance ◽  
Timber Harvest ◽  
Ecosystem Dynamics ◽  
Present Condition ◽  
Boreal Zone ◽  
Climate Change Effects ◽  
The Past

The boreal zone and its ecosystems provide numerous provisioning, regulating, cultural, and supporting services. Because of its resources and its hydroelectric potential, Canada’s boreal zone is important to the country’s resource-based economy. The region presently occupied by Canada’s boreal zone has experienced dramatic changes during the past 3 million years as the climate cooled and repeated glaciations affected both the biota and the landscape. For about the past 7000 years, climate, fire, insects, diseases, and their interactions have been the most important natural drivers of boreal ecosystem dynamics, including rejuvenation, biogeochemical cycling, maintenance of productivity, and landscape variability. Layered upon natural drivers are changes increasingly caused by people and development and those related to human-caused climate change. Effects of these agents vary spatially and temporally, and, as global population increases, the demands and impacts on ecosystems will likely increase. Understanding how humans directly affect terrestrial and aquatic ecosystems in Canada’s boreal zone and how these effects and actions interact with natural disturbance agents is a prerequisite for informed and adaptive decisions about management of natural resources, while maintaining the economy and environment upon which humans depend. This paper reports on the genesis and present condition of the boreal zone and its ecosystems and sets the context for a detailed scientific investigation in subsequent papers published in this journal on several key aspects: carbon in boreal forests; climate change consequences, adaptation, and mitigation; nutrient and elemental cycling; protected areas; status, impacts, and risks of non-native species; factors affecting sustainable timber harvest levels; terrestrial and aquatic biodiversity; and water and wetland resources.

Modulation of the relationship between summer temperatures in the Qinghai–Tibetan Plateau and Arctic over the past millennium by external forcings

2021 ◽  
pp. 1-9
Author(s):  
Feng Shi ◽  
Anmin Duan ◽  
Qiuzhen Yin ◽  
John T Bruun ◽  
Cunde Xiao ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Global Climate ◽  
Volcanic Eruptions ◽  
Warm Period ◽  
Temperature Correlation ◽  
The Past ◽  
External Forcings ◽  
Centennial Variation ◽  
Summer Temperatures ◽  
Past Millennium

Abstract The Qinghai–Tibetan Plateau and Arctic both have an important influence on global climate, but the correlation between climate variations in these two regions remains unclear. Here we reconstructed and compared the summer temperature anomalies over the past 1,120 yr (900–2019 CE) in the Qinghai–Tibetan Plateau and Arctic. The temperature correlation during the past millennium in these two regions has a distinct centennial variation caused by volcanic eruptions. Furthermore, the abrupt weak-to-strong transition in the temperature correlation during the sixteenth century could be analogous to this type of transition during the Modern Warm Period. The former was forced by volcanic eruptions, while the latter was controlled by changes in greenhouse gases. This implies that anthropogenic, as opposed to natural, forcing has acted to amplify the teleconnection between the Qinghai–Tibetan Plateau and Arctic during the Modern Warm Period.

scholarly journals Application of dendroclimatology in evaluation of climatic changes

2018 ◽  
Vol 64 (No. 3) ◽  
pp. 139-147 ◽  
Author(s):  
Khaleghi Mohammad Reza
Keyword(s):  
Climate Change ◽  
Tree Rings ◽  
Arid Regions ◽  
Ring Width ◽  
Climatic Changes ◽  
The Past ◽  
Temperature And Precipitation ◽  
Temporal And Spatial ◽  
Artificial Neural Network Ann ◽  
High Degree

The present study tends to describe the survey of climatic changes in the case of the Bojnourd region of North Khorasan, Iran. Climate change due to a fragile ecosystem in semi-arid and arid regions such as Iran is one of the most challenging climatological and hydrological problems. Dendrochronology, which uses tree rings to their exact year of formation to analyse temporal and spatial patterns of processes in the physical and cultural sciences, can be used to evaluate the effects of climate change. In this study, the effects of climate change were simulated using dendrochronology (tree rings) and an artificial neural network (ANN) for the period from 1800 to 2015. The present study was executed using the Quercus castaneifolia C.A. Meyer. Tree-ring width, temperature, and precipitation were the input parameters for the study, and climate change parameters were the outputs. After the training process, the model was verified. The verified network and tree rings were used to simulate climatic parameter changes during the past times. The results showed that the integration of dendroclimatology and an ANN renders a high degree of accuracy and efficiency in the simulation of climate change. The results showed that in the last two centuries, the climate of the study area changed from semiarid to arid, and its annual precipitation decreased significantly.

Comparison between Blue Intensity (BI) and Maximum Latewood Density (MXD) tree-ring chronologies from the North American Boreal forests

2020 ◽  
Author(s):  
Laia Andreu-Hayles ◽  
Rosanne D'Arrigo ◽  
Rose Oelkers ◽  
Kevin Anchukaitis ◽  
Greg Wiles ◽  
...  
Keyword(s):  
High Resolution ◽  
North America ◽  
Tree Ring ◽  
Boreal Forests ◽  
Ring Width ◽  
Maximum Latewood Density ◽  
Latewood Density ◽  
Tree Ring Data ◽  
Summer Temperatures ◽  
Blue Intensity

<p>Tree ring-width (TRW) and Maximum Latewood Density (MXD) series have been largely used to develop high-resolution temperature reconstructions for the Northern Hemisphere. The divergence phenomenon, a weakening of the positive relationship between TRW and summer temperatures, has been observed particularly in northwestern North America chronologies. In contrast, MXD datasets have shown a more stable relationship with summer temperatures, but it is costly and labor-intensive to produce. Recently, methodological advances in image analyses have led to development of a less expensive and labor-intensive MXD proxy known as Blue Intensity (BI). Here, we compare 6 newly developed BI tree-ring chronologies of white spruce (<em>Picea glauca</em> [Moench] Voss) from high-latitude boreal forests in North America (Alaska in USA; Yukon and the Northwestern Territory in Canada), with MXD chronologies developed at the same sites. We assessed the quality of BI in relation to MXD based on mean correlation between trees, chronology reliability based on the Expressed Population Signal (EPS), spectral properties, and the strength and spatial extent of the temperature signal. Individual BI chronologies established significant correlations with summer temperatures showing a similar strength and spatial cover than MXD chronologies. Overall, the BI tree-ring data is emerging as a valuable proxy for generating high-resolution temperature spatial reconstructions over northwestern America.</p>

Central European vegetation and climate dynamics during the past 130 ka at Füramoos, SW Germany

2020 ◽  
Author(s):  
Oliver Kern ◽  
Frederik Allstädt ◽  
Andreas Koutsodendris ◽  
Bertil Mächtle ◽  
Gerd Schukraft ◽  
...  
Keyword(s):  
Climate Change ◽  
Boreal Forests ◽  
Pollen Record ◽  
Short Term ◽  
Central European ◽  
The Past ◽  
The Alps ◽  
Mis 5E ◽  
Insight Into ◽  
The Last Glacial

<p>To better understand the response of Central European vegetation to rapid climate change during the late Quaternary, we have revisited the Füramoos peat bog in southwestern Germany. Located between two moraine ridges of Rissian age and comprising a near-complete sedimentary sequence from late Marine Isotope Stage (MIS) 6 to 1, this peat bog represents the longest continuous pollen record from the last glacial-interglacial cycle north of the Alps. The Füramoos site has been in the focus of several palynological studies in the past, showing that it presents an excellent archive to study the impact of Dansgaard-Oeschger (D-O) events on the Central European ecosystems (e.g., Müller et al., 2003). However, these previous studies were only of limited temporal resolution, which has yet precluded detailed insight into the ecosystem response to short-term climate change. We present a new, highly resolved pollen record (temporal resolution: 80–200 yrs) and XRF core scanning data from Füramoos spanning the past ~130 ka based on two new drill cores that consist of peat and lake sediments (Kern et al., 2019).</p><p>Our results show that closed temperate forests thrived at Füramoos during full interglacials characterized by <em>Alnus</em>, <em>Corylus</em>, <em>Quercus</em>, and <em>Ulmus</em>. The major difference between the past two interglacials is that <em>Fagus</em> dominates during MIS 1 whereas it is mostly absent during MIS 5e. During MIS 5, the vegetation evolved from closed temperate (MIS 5e) to boreal forests (dominated by <em>Betula</em>, <em>Picea</em>, and <em>Pinus</em>; MIS 5d–5a). The youngest part of the last interglacial (MIS 5d–5a) is marked by six distinct forests contractions (decreases in arboreal pollen by ~30–50%) before the establishment of a steppe vegetation that prevailed throughout the Last Glacial (MIS 2–4). In addition, seven transient increases in tree-pollen percentages document the expansion of boreal forests during MIS 2–4; they are associated with synchronous increases of Si, Ti, K and Fe contents as evidenced in XRF data.</p><p>We attribute the forest contractions during MIS 5d–5a to the cooling events C19–C24 known from marine records in the North Atlantic and terrestrial records from southern Europe. Moreover, the forest expansions during MIS 2–4 are associated with warm and moist conditions occurring during D-O events 7–12, and 14. In contrast, D-O events 13 and 15–19 don’t leave an imprint on the vegetation although their presence is clearly documented in the XRF data. Our findings emphasize that the sediments from Füramoos are exceptionally well suited to reconstruct ecosystem dynamics in Central Europe yielding unprecedented insight into the vegetation response to short-term climatic forcing north of the Alps during the past 130 kyrs.</p><p> </p><p>Müller, U.C., Pross, J., Bibus, E., 2003. Vegetation response to rapid climate change in Central Europe during the past 140,000 yr based on evidence from the Füramoos pollen record. <em>Quaternary Research</em> 59, 235–245.</p><p>Kern, O.A., Koutsodendris, A., Mächtle, B., et al., 2019. X-ray fluorescence core scanning yields reliable semiquantitative data on the elemental composition of peat and organic-rich lake sediments. <em>Science of the Total Environment</em> 697, 134110.</p>

Human resilience and resettlement among the Islands of Four Mountains, Aleutians, Alaska

2019 ◽  
Vol 91 (03) ◽  
pp. 917-933 ◽  
Author(s):  
Virginia L. Hatfield ◽  
Kirsten Nicolaysen ◽  
Dixie L. West ◽  
Olga A. Krylovich ◽  
Kale M. Bruner ◽  
...  
Keyword(s):  
Climate Change ◽  
Volcanic Eruption ◽  
Volcanic Eruptions ◽  
Aleutian Islands ◽  
Human Settlements ◽  
Archaeological Evidence ◽  
The Past ◽  
Human Ecodynamics ◽  
The Face

AbstractCombined archaeological, ecological, and geologic research on Chuginadak and Carlisle Islands in the Islands of Four Mountains (IFM) probed questions about the sustainability of human settlements over the past 4000 years in the face of geologic, ecological, and social hazards. We use a human ecodynamics approach to frame the investigation and present original archaeological evidence from this poorly known region of the remote Aleutian Islands. Several village sites occupied during the last four millennia are clustered in locations that were not damaged by earthquake-induced tsunamis; however, new geologic evidence indicates that at least one volcanic eruption forced humans to abandon one or more prehistoric village sites. Combined archaeological, ecological, and geologic analyses demonstrate resilient Unangax̂ occupations of the IFM through long-term climate change as well as earthquakes, tsunamis, and volcanic eruptions with occasional community vulnerability to volcanic eruptions.

scholarly journals Climate Response of Metasequoia glyptostroboides Inferred from Tree Rings, Secrest Arboretum, Wooster, Ohio, USA

2020 ◽  
Vol 120 (2) ◽  
pp. 22
Author(s):  
Lauren J. Vargo ◽  
Gregory Wiles ◽  
Nicholas Wiesenberg ◽  
Christopher J. Williams ◽  
Ken Cochran
Keyword(s):  
Climate Change ◽  
Annual Ring ◽  
Ring Width ◽  
Climate Response ◽  
Physiological Plasticity ◽  
Metasequoia Glyptostroboides ◽  
Annual Ring Width ◽  
Confidence Levels ◽  
Maximum Temperatures ◽  
Moisture Conditions

Metasequoia glyptostroboides, a deciduous gymnosperm, also known as dawn redwood, was thought to be extinct until living members of the species were found in China in 1943. Analyzing the climate response of a transplanted stand of the trees can give insights into their physiological plasticity, into their use in restoration and reforestation, as well as into interpreting the environmental conditions of the geologic past from fossil Metasequoia. An annual ring-width chronology—spanning 1955 to 2010 and based on a stand of 19 M. glyptostroboides trees planted in Secrest Arboretum in northeast Ohio, USA—shows negative correlations with maximum monthly temperatures: with the strongest relationship with February and the warm months of June and July, all significant at the 99% confidence levels. A positive May to June precipitation correlation is the strongest moisture signal (p < 0.05) and the narrowest rings in the chronology occurred during the drought of 1987 to 1988, consistent with one of the warmest and driest Junes on record. These results have implications for the future as climate change affects the native and transplanted range of this species. Future response of this species to a changing climate will depend on the relative rates of warming maximum temperatures in the winter and summer, as well as changing moisture conditions during the summer months.

Anthropo-generated Climate Change in Europe

1992 ◽  
Vol 19 (4) ◽  
pp. 349-353 ◽  
Author(s):  
Robert C. Balling ◽  
Sherwood B. Idso
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
Strong Support ◽  
Surface Air Temperature ◽  
The United States ◽  
The Past ◽  
Temperature And Precipitation ◽  
Temperature Trends ◽  
Wide Range ◽  
Northern Hemispheric

In reviewing the results of our analyses of European temperature and precipitation data, we see patterns that are similar to those discovered in our prior studies of the United States and the British Isles: precipitation begins to increase at about the time that Northern Hemispheric SO2 emissions began their rapid ascension, while prior upward trends of surface-air temperature are dramatically truncated.We also find that surface-air temperature trends of different localities over the past three-and-a-half decades are closely tied to the amount of aerosol sulphates in the atmosphere above them. The wide range and thrust of these several observations, along with their theoretical expectation, provides strong support for the premise that anthropo-generated climate change is indeed occurring in Europe, but that it may well be SO2-induced rather than CO2-induced.

scholarly journals 6000-Year Climate Records in an Ice Core from the Høghetta Ice Dome in Northern Spitsbergen

1990 ◽  
Vol 14 ◽  
pp. 85-89 ◽  
Author(s):  
Y. Fujii ◽  
K. Kamiyama ◽  
T. Kawamura ◽  
T. Kameda ◽  
K. Izumi ◽  
...  
Keyword(s):  
Ice Core ◽  
Volcanic Eruptions ◽  
The Arctic ◽  
Bottom Temperature ◽  
Air Bubble ◽  
The Past ◽  
Melt Water ◽  
Time Gap ◽  
Northern Hemispheric ◽  
Last 300 Years

In 1987 an ice core to the bedrock at a depth of 85.6 m was drilled at the top of Høghetta ice dome in northern Spitsbergen. Chronology of the ice core was examined by tritium and14C methods showing time gap at about 50 m depth. The age of three bottom ice samples was determined as 4150–5670 year B.P. by14C method done for frozen bacteria colonies and a frozen petal. This chronology and negative bottom temperature of −9.4°C suggest that glaciers in Spitsbergen shrank considerably during the hypsithermal. The pH of melt-water samples lower than 5.0 corresponds well to large northern hemispheric volcanic eruptions during the last 300 years. Increase of acidity from 30 m depth to the surface may reflect the spread of air pollution to the Arctic during the past 200 years. On the basis of ice-core analyses on electrical conductivity, pH, chemical composition and air bubble pattern, climate and environment in Spitsbergen during the last 6000 years are discussed.

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