| Summary: | 碩士 === 國立臺灣大學 === 地質科學研究所 === 99 === The width and density of tree-ring is not only affect by climate, but the pathological structure, such as false ring, also reflect the change of climate.
Ring growth and the presence of false rings were studied in Chamaecyparis obtusa var. formosana growing in the Mt. Chilan area. Five tree-ring parameters, including total ring width (RW), earlywood width (EW), latewood width (LW), maximum density (MaxD), minimum density (minD), were obtained by soft x-ray image-analysis method. The five tree ring chronologies and false ring proportion from 1960 to 2009 A.D. have been established by soft x-ray image-analysis method, cross dating and ARSTAN program.
The correlations between the above five parameters and climate data from Ilan station indicate monthly mean temperature is more sensitive to tree-ring width than monthly precipitation. Most false rings were found in the earlywood. The year of coourence of false ring contrast to climate data of April-October at the same year, the results show: (1) The appearances of false ring in the earlywood are relative to the anomaly of high temperature or precipitation in May, or an abnormal high temperature in July. (2) The false rings in the latewood appear under an abnormal low temperature in October. (3) The false rings are most likely related to the typhoon events of July and August.
Overall, false ring is an unique feature in tree ring and can be applied successfully in dendroclimatic studies.
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