Assessing Wooden Material Application in Ecological Engineering Methods in Taiwan

Abstract

The Central Taiwan region suffered severe damage caused by debris flow during the disastrous Chi-Chi Earthquake in 1999, Typhoon Toraji and Nali in 2001. Rehabilitation work was undergoing by the authorities who invested a great deal of money and resources. Part of the work adopted the ecological engineering techniques to reconstruct the facilities such as the articulated blocks bank, gabion and geogrid walls by the ”local material was utilized first” principle to reduce the usage of concrete. Some of these facilities based on the design of ecological techniques, which was made of wooden material, had passed the test of Typhoon Mindulle in July of 2004. However, few studies were focused on the design, monitoring and assessment of the wooden material applied on ecological works in Taiwan. This study analyzes some ecological works made of wooden material by the Forest Bureau, the Soil and Water Conservation Bureau and National Taiwan University Experimental Forest where these works are located in Yilan and Nantou County respectively. The displacement, strength, rottenness and water content of wooden structure, along with the recovery benefits were monitored and assessed in this study. The preliminary results show that the displacement and rottenness of wooden material works is minor and the safety is quite well subject to the subsequent typhoons and large rainfall events between 2006 and 2007. Besides, the vegetation spreads well over the works and merges with the environment after the wooden material works are finished and the abundance is also investigated to stand for the recovery effect of these works. Further, by comparing wooden ecological works with concrete ones, the former can obviously decrease the amount of carbon dioxide emission and increase sequestration of carbon in the material. The result provides a key reference to set the design regulations and rules in the future.