Study on the Effect of Environmental Change on the Golden Hall of Chusonji Temple

中禅寺的金殿（Konjiki-do）现在被保存在一个巨大的玻璃陈列柜里。1990年，由于旧陈列柜没有足够的密封，陈列柜得到了改进。由于改善，室内平均湿度从80%变为65%，导致木材收缩，表面漆器层开裂。这项研究的目的是了解收缩是否会继续。如果没有，他们可以考虑修复。完成了以下测量：展柜内的温度和湿度，两个木材之间的间隙宽度和漆层的应变。箱内湿度稳定在65%左右，温度随季节变化在5 ~ 25℃之间。两根木材之间的间隙宽度也会根据季节变化约0.4毫米。它在1995年略有扩大，但在1996年至1997年的平均水平几乎稳定。然而，随着季节的变化，褐虫层的菌株仍然会增加。这些结果告诉我们，经过10年的改进，木材的收缩可能已经停止，但漆层的应变仍然存在，这将导致进一步的裂缝。应变保持不变的原因可能是木材收缩后对其表面漆木层施加了应力。

Golden Hall (Konjiki-do) of Chusonji Temple is stored now within a large glass showcase. The showcase was improved in 1990 because an old one was not enough sealed from outside. The average humidity inside changed from 80% to 65% due to the improvement, which caused shrinkage of wood and cracks of urushi (Japanese lacquer) layr of the surface. The study was intended to know whether the shrinkage continues or not. If not, they can think about the restoration.Following measurements were done : temperature and humidity within the showcase, width of a gap between two timbers and strain of a urushi layr. The humidity inside is almost stable at 65% while the temperature changes from 5ﾟC to 25ﾟC according to seasons. The width of a gap between two timbers also changes about 0.4mm according to seasons. It became slightly larger in 1995 but was almost stable from 1996 to 1997 in average. The strain of an urushi layr, however, still increases with some seasonal changes.These results tell us that the shrinkage of wood probably ceased after ten years of the improvement but the strain of an urushi layr still remains, which would cause a further crack. The reason why the strain remains may be because a shrank timber gives a stress to its surface urushi layr.