نتایج جستجو برای: birch (tree)

تعداد نتایج: 174023  

2005
Benjamin F. Clegg Willy Tinner Daniel G. Gavin Feng Sheng Hu

Lake sediments from arcto-boreal regions commonly contain abundant Betula pollen. However, palaeoenvironmental interpretations of Betula pollen are often ambiguous because of the lack of reliable morphological features to distinguish among ecologically distinct Betula species in western North America. We measured the grain diameters and pore depths of pollen from three tree-birch species (B. pa...

Journal: :MCFNS 2013
Chris J. Cieszewski Mike R. Strub Finto Antony Pete Bettinger Joseph Dahlen Roger C. Lowe

We estimated wood quality parameters for a specific tree trunk using samples of this tree’s branch, and auxiliary samples from other similar species, based on analysis of wood density, modulus of elasticity (MOE), and microfibril angle (MFA), measured with the near-infrared spectroscopy (NIRS) and SilviScan processes. The measured materials included a branch sample from the subject tree, also k...

Journal: :Annals of botany 2004
Thorbergur Hjalti Jónsson

BACKGROUND AND AIMS Sub-arctic mountain birch Betula pubescens var. pumila communities in the North Atlantic region are of variable stature, ranging from prostrate scrubs to forests with trees up to 12 m high. Four hypotheses were tested, relating growth and population characteristics of sub-arctic birch woodland and scrub to tree stature; i.e. the variable stature of birch woods is due to diff...

2011
Mats Fröberg Karna Hansson Dan Berggren Kleja Ghasem Alavi

The effects of three common tree species – Scots pine, Norway spruce and silver birch – on leaching of dissolved organic carbon and dissolved nitrogen were studied in an experimental forest with podzolised soils in southern Sweden. We analyzed soil water collected with lysimeters and modeled water fluxes to estimate dissolved C and N fluxes. Specific UV absorbance (SUVA) was analyzed to get inf...

2017
Svitlana Zubchenko Valentyna Chopyak Olena Gubska Sergey Yuryev Fernando Pineda

The study involved 286 patients (17-58 years, 55.9% females and 44.1% males). SPT was performed with extracts “Mixture of trees” (Diater Laboratorios, Spain). The study of allergen components was made by ImmunoCAP. We evaluated the efficiency of SLIT by visual analogue scale. 98.3% patients had positive SPT to extract “Mixture of trees”. N=281:191 (68.1%) individuals were positive to birch extr...

2016
Kyoung Yong Jeong Mina Son Jin Hee Park Kyung Hee Park Hye Jung Park Jae-Hyun Lee Chein-Soo Hong Jung-Won Park

Oak and birch trees belong to Fagales order. Specific IgE to pollen allergens of both trees are frequently found in Korea pollinosis patients. Oak trees which comprise 40% of forest area are common in Korea. However, birch trees are sparse. We compared the allergenicity of pollen extracts of white oak, sawtooth and Mongolian oaks which are prevalent species in Korea, with the pollen extract of ...

2017
Diem Nguyen Johanna Boberg Michelle Cleary Helge Bruelheide Lydia Hönig Julia Koricheva Jan Stenlid

Foliar fungi of silver birch (Betula pendula) in an experimental Finnish forest were investigated across a gradient of tree species richness using molecular high-throughput sequencing and visual macroscopic assessment. We hypothesized that the molecular approach detects more fungal taxa than visual assessment, and that there is a relationship among the most common fungal taxa detected by both t...

ژورنال: کومش 2020

Introduction: Clustering of human brain is a very useful tool for diagnosis, treatment, and tracking of brain tumors. There are several methods in this category in order to do this. In this study, modified balanced iterative reducing and clustering using hierarchies (m-BIRCH) was introduced for brain activation clustering. This algorithm has an appropriate speed and good scalability in dealing ...

Journal: :Forests 2021

Himalayan Silver Fir (Abies spectabilis) and Birch (Betula utilis) are tree species often found coexisting in sub-alpine forests of the Nepal Himalayas. To assess species-specific growth performances these species, tree-ring samples were collected from subalpine forest Dhorpatan Hunting Reserve, Nepal. Standard ring width chronologies both correlated with climatic variables static running windo...

2000
Changbai Mountain YU Da-pao GU Hui-yan WANG Jian-dong WANG Qing-li DAI Li-min

Based on the tree-ring growth characteristics of Erman’s birch (Betula ermanii charm.) and the relationships between it and climatic factors at elevation of 1950m, the sensitivity of tree lines in Changbai Mountain to climatic factors was assessed. The results indicated tree line forest in Changbai Mountain had an obvious sensitivity to climate factors. However, difference from other study sits...

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