In Japan, coastal forests have been constructed along the seashore to prevent houses and fields from disasters caused by strong winds. A management method needs to be established to regulate the stand density. There is also the possibility that wind speed will increase in the future because of the increasing strength of tropical cyclones caused by climate change. We evaluated the current and future risk of wind damage associated with strip cutting of Japanese black pine forest based on moment work on sample trees. We established a research site consisting of three groups of trees: group A faced a 1.2-m cutting strip, group B faced a 5-m cutting strip, and group C was the control. Group B was vulnerable to strong winds because the normalized critical wind speed (CWSnml) was significantly smaller than that in the other groups. The damage risk was evaluated by comparing CWSnml with the criterion, a 50-year return period of wind speed. In the current conditions, 5-m cutting had a certain degree of risk, and 1.2-m cutting showed a low risk. Under the future wind conditions, 5-m cutting was found to show high risk so that most of the trees did not meet the criterion. The 1.2-m cutting showed a low risk even in the future conditions. Our results clearly reveal the significant changes in the stability of remaining trees against strong winds after strip cutting. This study suggests a method to quantify the risk involved in forest management.
Regulating strip cutting to ensure enough wind protection from constructed pine coastal forests in Japan. This is an experimental study to determine the optimal strip cutting width Sakamoto et al. (2010) discussed the importance of regulating the stand density while avoiding disasters in coastal areas. Strip cutting is a method used to manage forests by making row-cut blocks at regular intervals. It is usually performed to regulate the stand density by cutting with a narrow width or to encourage regeneration with a relatively wide width. In 2010, strip cutting was performed in a N30E–S30W direction as an attempt to manage the naturally regenerated forest [note – this is natural regeneration of an artificial/constructed pine] with very high stand density by Aichi Prefecture. Strip cutting of one line and the remaining three lines of trees is often performed in coastal forests in Japan (Sakamoto et al. 2007). Strip cutting with widths of 1.2 m in this study was performed every 3.6 m of the remaining trees, mimicking the regular management. On the other hand, strip cutting with a width of 5 m is also performed for carrying the harvested trees out of the stands easily. Considering these practical methods of strip cutting, we used the width of 1.2 m as standard strip cutting width and 5 m as wider strip cutting width in this study “The forest was originally established during 1952–1956 by authorities in Aichi Prefecture. However, it is now a naturally regenerated forest after severe damages by primarily two events, a typhoon in 1959 and pine wilt disease that started in 1975 caused by nematodes.”
|Climate change impacts
|Effect of Nbs on CCI
|normalized critical wind speed (CWSnml); derived from mechanical modeling
Japanese black pine forest in Ichizenmatsu, Aichi Prefecture, Japan