Impacts of Reforestation on Stabilization of Riverine Water Levels in South Korea

We investigate how reforestation contributed to stabilization of riverine water levels in South Korea. For the purpose, we estimate an equation capturing dynamic relationships among rainfall, upstream-area tree stock, and downstream water levels in three river systems of Hongcheon, Mangyeong, and Hyeongsan, using daily observations of precipitation and water levels for the period from 1985 to 2005. Simulation based on estimation results shows that increase in the tree stock in a river basin leads to a significantly suppressed peaking in riverine water levels in response to an abrupt and concentrated rain in the upstream area. For instance, an hour-long concentration of 100mm rain results in 0.7m rise in water level if the volume of growing stock is 1 million m3 , whereas the rise in water level stays below 0.27m with 5 million m3 in the growing-stock volume

Exchange rate volatility and exports from East Asian countries to Japan and the USA

The purpose of this article is to investigate the impact of exchange rate volatility on exports in four East Asian countries (Hong Kong, South Korea, Singapore, and Thailand). Specifically, this article aims at determining whether the bilateral real exchange rate volatility between an East Asian country and its trading partner negatively affects the exports of the East Asian country. Considering the dominant roles of the USA and Japan as trading partners of those East Asian countries, this article focuses on the quarterly export volumes of East Asian countries to the US and Japan for the period from 1981 to 2004. Except for the case of Hong Kong's exports to Japan, cointegration tests and estimations of error correction models indicate exchange rate volatility has negative impacts on exports either in the short-run or in the long-run, or both. On the other hand, the real GDP of importing countries and depreciation of real bilateral exchange rates turn out, in general, to have positive effects. Of special interest is the finding that the impact of the exchange rate volatility does not show any stylized differences depending on whether the importing country is Japan or the USA, even though dollar invoicing dominates in East Asia.