نتایج جستجو برای: tree rings

تعداد نتایج: 217757  

Journal: :IOP Conference Series: Materials Science and Engineering 2021

2008
M. Stoffel

The understanding of geomorphic processes and knowledge of past events are important tasks for the assessment of natural hazards. Tree rings have on varied occasions proved to be a reliable tool for the acquisition of data on past events. In this review paper, we provide an overview on the use of tree rings in natural hazards research, starting with a description of the different types of distu...

2009
Miranda Froehlich Dean Wilder

Dendrochronology is the science that uses tree-rings dated to their exact year of formation to analyze temporal and spatial patterns of processes in the physical and cultural sciences. There currently is no published record for tree-ring studies using Eastern Red Cedar in the Upper Mississippi River Valley in Wisconsin. Therefore, this study develops a chronology from treerings using Eastern Re...

Journal: :محیط شناسی 0
بفرین معروفی اقدم دانشجوی کارشناسی ارشد جنگلداری، گروه جنگلداری، دانشکدۀ منابع طبیعی، دانشگاه گیلان مهرداد قدس خواه دریایی استادیار جنگلداری، گروه جنگلداری، دانشکدۀ منابع طبیعی، دانشگاه گیلان جواد ترکمن استادیار جنگلداری، گروه جنگلداری، دانشکدۀ منابع طبیعی، دانشگاه گیلان سرخوش کرم زاده کارشناس ارشد جنگلداری، کارمند اداره منابع طبیعی و آبخیزداری آستارا

introduction climate change happens due to abnormal changes of climate within the earth’s atmosphere and their consequences. one of the most significant effects of climate change is the irreversible damage to some floral species and forest ecosystems. tree species reflect the impact of climate changes on their ring width. generally, tree rings vary in size each year depending upon the environme...

Journal: :international journal of environmental research 0
o.i. shumilov institute of north industrial ecology problems, kola science centre ras, apatity, russia e.a. kasatkina institute of north industrial ecology problems, kola science centre ras, apatity, russia k. mielikainen finnish forest research institute, vantaa research unit, vantaa, finland m. timonen finnish forest research institute, rovaniemi research unit, rovaniemi, finland a.g. kanatjev institute of north industrial ecology problems, kola science centre ras, apatity, russia

the paper deals with the analysis of the external factor (solar activity, volcanic eruptions) influence on tree growth at the kola peninsula, northwestern russia. pinus sylvestris l. (scots pine) tree-ring chronologies collected nearby the northern timberline (68.63n, 33.25e) include the oldest (1445-2005 ad) living pine tree found up to date in the kola peninsula. a total of 18 living trees pi...

Journal: :جغرافیا و مخاطرات محیطی 0
محسن ارسلانی قاسم عزیزی فرامرز خوش اخلاق

introduction iran is located in a semi arid region of the world. in recent years, dramatic changes in the form of increasing in maximum temperature and severe droughts have damaged water resources, local forests and agriculture. in the mid- and high latitudes of the northern hemisphere the warmest years have been recorded in recent decades (ipcc, 2007). in order to fully understand the climatic...

Journal: :Climate Dynamics 2021

Tree-rings are one of the most commonly used proxies for reconstructing past climates at annual resolution. The climate information is generally deduced from tree-rings using statistical relationships, but assumed linearity and stationarity may be inadequate. Process-based models allow non-stationarity non-linearity; however, many challenges associated with their application global scale recons...

1996
Christos Kaklamanis

We address the issue of eeciently assigning wavelengths to communication requests in wavelength division multiplexing (WDM) optical networks. We consider directed tree and tree of rings topologies. These are topologies of concrete practical relevance for which undirected underlying graph models have been studied by Raghavan and Upfal 6]. Directed models were rst studied by Mihail et al 4]. For ...

2011
J. M. UPRICHARD

The distribution of extractives, lignin, and carbohydrates in radiata pine and their variation with tree age are reviewed. Extractives, their nature, and amount depend on the heartwood content of the tree, and thus upon wood age. Lignin decreases in the pith-to-bark sequence; pentosans content decreases over the first 10-15 growth rings from the pith, after which it is approximately constant. C...

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