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Hebei Normal University (2021)

The Characteristics of Annual Ring Width of Tamarix Shrub in Lop Nor Area and Its Response

孟祥彪

Titre : The Characteristics of Annual Ring Width of Tamarix Shrub in Lop Nor Area and Its Response

Auteur : 孟祥彪

Grade : Master 2021

Université : Hebei Normal University

Résumé partiel
Genetic and ecological factors are the main factors affecting the growth of trees.The influence of external environment on the growth and development of trees can be reflected by the width of tree rings.Lop Nor region is one of the most representative regions of environmental change in arid areas of China and even the world.Due to its special geographical location,harsh environment and exceptionally fragile ecosystem,Lop Nor region is very sensitive to global climate change.Although the harsh climate conditions in Lop Nor area limit the growth and development of trees,Tamarix shrubs and other shrubs are widely distributed in some areas.The study on the width characteristics of Tamarix shrubs in this area and its response to local environmental changes is of great significance for the implementation of ecological protection in Lop Nor area in the future.In this paper,the Tamarix tree ring in Lop Nor area was taken as the research object,and a series of stem sampling methods were adopted to collect the Tamarix wheel,and the timely processing,cross-dating and growth ring width measurement were carried out strictly in accordance with the standard of growth ring experiment.Different habitats in this paper,we study the Lop Nor were systematically stud Ed under Philippine wheel brush tree characteristics and differences,and USES the correlation analysis for the annual ring width of four areas and regional differences in the correlation of temperature,precipitation and its response to the environmental elements relations,Philippine thickets to a deeper understanding of the Lop Nor were systematically stud Ed the changing rule of the ecosystem,to protect its ecological system and used to provide theoretical basis.The main conclusions are as follows :(1)In Lop Nor area,the color of Tamarix shrubs tree rings early wood is lighter and pale yellow,and the color of late wood is darker and dark red,with very clear boundaries.Affected by its own genetic characteristics and extreme habitats,the eccentricity of Tamarix shrubs growth is common.There are single or multiple growth areas in some tree rings,and the morphology of the tree disk is irregular,such as a star or fan.(2)The number of tree rings of sapwood in Tamarix shrubs in Lop Nor area is mainly concentrated between 4-5 rings,accounting for more than 79% of the total sample,of which 4 rings are the most,accounting for 49% of the total sample.There is no obvious relationship between the number of sapwood and tree age.The width of the sapwood band is wider in young tree stems and narrower in old trees.(3)The width of the annual ring of Tamarix shrubs in the study area is relatively small,basically below 1 mm.There are also obvious differences in the annual ring width of Tamarix shrubs in different regions.The average annual ring width of the four sampling points is 0.83-1.21 mm,of which the Hongliugou area is the largest with 1.21mm ;the second is Hongliujing and Yingpan regions,with0.91 mm and 0.83 mm respectively ;the average annual ring width in Milan is the smallest.It is 0.82 mm.

Mots clés : Lop Nor ;Tamarix bush ;Bush Annual Rings ;Regional Environment ;

Présentation (CNKI)

Page publiée le 19 novembre 2021