1 Introduction Since Douglass established the principles and methods of chronology, tree ring has been the main research object of tree chronology. The ring is a recorder that records climate and environmental changes. . The use of annual ring width to reconstruct rainfall and temperature changes over the past hundreds or even thousands of years, and the use of annual ring density analysis and changes in element concentration in annual rings to infer past environmental changes have become one of the important means of global change research. Scholars from various countries in Europe and the United States are very popular in using tree-ring data to study climate and environmental factors, especially environmental pollution changes. In the 1980s, China began to use tree-rings to study environmental pollution. At present, there is usually no problem in measuring the width of the tree ring, but many studies have proved that the average density of annual rings, especially the density of morning and evening wood, is more sensitive to climate change than the width of the annual rings. Measurement has always been very difficult. Since the late 1940s, researchers have tried different tree ring density measurement methods, including volumetric-gravimetric methods, light transmission, Hardness, and tensile strength. Measurement method (Tensile strength), β particle method (Beta particles), etc. Each method is based on different working principles and has its own characteristics, but for tree chronology research, they all have different degrees of restrictions, so that they cannot be widely used in this study. Until the 1960s, with the successful application of X-ray technology in the study of chronology of trees, the study of tree ring density and annual ring elements gradually emerged. The obtained annual ring density, annual ring element concentration and other indicators were The analysis of the impact of environmental factors on tree growth provides a new basis for opening up new areas for the development of tree-ring climatology. 2 Analysis system design 2.1 Objective The AZ-F0200 annual ring element analysis system mainly takes the tree-like core removed by the growth cone as the object, obtains a high-resolution image of the tree-like core through a high-quality graphics scanning system, and uses a special lighting system to remove shadows and unevenness And then use professional software to analyze the annual ring width and density. For the tree-like core, through the world's most advanced annual ring element analyzer combined with X-ray imaging and XRF element analysis technology, the annual ring density image of the sample and various element distribution images are obtained to determine the Al, Concentration of Si, S, Cl, K, Ca, Cr, Mn, Fe, Cu, Zn, As, Hg, Pb and other elements, and density analysis using professional software. Using the above tree ring width and density determination and annual ring element analysis results, a tree ring table is established to explore the relationship between the growth of different tree species and climatic factors, and speculate on past environmental changes, especially environmental pollution. According to the meteorological data in the region and the tree ring information in the same period, the correlation between the tree ring data and the meteorological data is established, and the climate change spectrum of the typical climate zone is reconstructed accordingly to further reveal the impact of climate change on the forest ecosystem. 2.2 Sampling settings Select areas where tree growth is very sensitive to changes in environmental factors (temperature, precipitation, etc.). In the sampling layout, select locations with thin soil layers, large slopes, and less influenced by human activities. According to different research purposes, plots are set according to factors such as altitude, aspect, and position. 2.2.2 Sample tree selection The sample of the same tree species in each plot is 20-30 plants, 20 plants in the north are suitable, and 30 plants in the south are suitable. Choose trees at the base of the tree, with no animal caves at the roots, no stems, and straight trunks. In order to rebuild the longest annual ring climate change spectrum, old trees should be selected, including old dead trees. 2.2.3 Sample collection In order to reconstruct the longest annual ring climate change spectrum, select old trees including dead old trees. Live trees are sampled at the breast diameter of the trunk with a growth cone. The direction is generally consistent with the direction of the contour of the slope, or perpendicular to the slope of the slope. The sampling direction in the same plot must be consistent. The dead tree is intercepted and sampled at a uniform place in the trunk (tree section). When sampling with the Haglof growth cone, first remove the cone and install it on the cone shank, then level the growth cone end, stand firmly under the feet, hold the two ends of the cone shank with both hands, the front spiral edge is aligned with the tree, and rotate the cone shank. When the cone crosses the center of the tree, stop rotating the cone handle. Use a core spoon to extract the drill core, tightly attach the tip of the spoon to the inner wall of the cone, and extract the drill core smoothly and quickly and place it in the drill box. 2.3 Sample collection time and frequency Trees with a dormant period should be carried out during the dormant period of trees, and trees without a dormant period can be sampled at any time of the year. 2.4 Analysis indicators Annual ring width, early wood width, late wood width, early wood density, late wood density, annual ring density, maximum annual ring density, minimum annual ring density, early wood late wood boundary density, annual ring element content. 2.5 System composition and technical indicators AZ-F0200 annual ring element analysis system is composed of growth cone, annual ring width analysis unit, annual ring density and element analysis unit. Technical index: Growth cone: diameter 4.35mm, 5.15mm, 10mm, 12mm optional, length range 100mm ~ 1000mm. The two-wire threaded drill bit can be turned into 8mm per one rotation; the three-wire threaded drill bit can be turned into 12mm per one rotation. Annual ring width analysis unit: Scanner: Resolvable minimum particle size 0.005mm / 0.011mm Analysis software: It can measure annual rings in horizontal and vertical directions, judge invalid annual rings and estimate lost annual rings. It can measure the width of the annual ring, the width of the wood sooner or later, and can calculate the maximum, minimum, average and direction of the density of the annual ring. Annual ring density and element analysis unit: Can measure Mg, Al, Si, S, Cl, K, Ca, Ti, Ba, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Pb and other element concentrations, accuracy 1ppm; Measuring principle: X-ray fluorescence analysis (XRF) and digital X-ray imaging technology; Console: a 300x200mm X / Y mobile computer console with a scanning spot length of 2.5 microns; sample slot: up to 9 wooden strip samples with a length of 280mm and a width of 7 ~ 12mm; Analysis software: users can choose the analysis area, resolution and scan time, batch work function supports unattended batch measurement, and can obtain density curves of various elements 3 Data processing 3.1 Establishment and test of reconstruction equation Using data such as tree ring width, tree ring density and ring element concentration, and necessary meteorological data, a single correlation, stepwise regression analysis method is used to establish a regression equation, and error reduction value, sign test, product average, and one by one are eliminated Method to test the regression equation. 3.2 Characteristic analysis of reconstruction results Mainly include change stage analysis, period analysis, maximum entropy spectrum analysis, frequency extreme value analysis, trend analysis and mutation characteristic analysis. 3.3 Comparison of reconstruction results Use the available data to compare the reconstruction results with those obtained by other researchers, generally including stage comparison, mutation comparison, and trend comparison. 4 Application case 4.1 The picture below is the scan result of a pine wood sample on the scanner bracket of the annual density element analysis unit, with a scanning resolution of 50 microns. The background is black, and the wood is presented in color. The radiographic images are superimposed in anti-gray scale, and the blue broken line is the calcium element profile. 4.2 The Saima Environmental Science Center uses the annual ring density element analyzer to study the density of European red pine. D-glutamic acid is present in very low levels. However, in recent years, it has been found that D-glutamate also has an important role in some biological processes. For example, D-glutamic acid can promote neuronal growth and repair, and has potential for treating neurodegenerative diseases D-Glutamic acid,H-D-Glu-OH,6893-26-1,C5H9NO4 Mianyang Shengshi Health Technology Co.,Ltd , https://www.shengshiaminoacid.com
