Monitoring of the Trend of Timberlines in Taiwan Amidst Climate Change Through Multi-Temporal Satellite Images

Global warming is becoming more and more obvious hastening the effect of climate change and at the same time affecting the growth of plants. Under global warming, the growth of vegetation is affected by climatic factors such as temperature and rainfall, which have also led to changes in the structure of the timberline and its distribution along the altitudes. In order to observe the trend of timberline in Taiwan under global warming, this study focused on Yushan peaks as study site, which represents the Taiwan's alpine ecosystem, using multi-temporal Landsat 8 satellite images that were acquired in 2013, 2016 and 2019 and meteorological data. The satellite images were atmospherically corrected using the FLAASH and pansharpened using the NNDiffuse technique. The different land cover in Yushan namely forest, low vegetation, bareland, and river were classified using the SVM supervised classification. The changes in the distribution of trees in different periods with the changes in the meteorological data were identified, classified, analysed and compared. The results of the study show that the current impact of global warming to climate change and on Taiwan's timberline trend is caused mainly by temperature. The rising temperature overtime had caused the timberline to shift towards the higher altitudes.