2009 Volume 13 Issue 1_2 Pages 5-13
Aiming to clarify the mechanism of beech forest declines on the Tanzawa Mountains, we conducted field surveys on such three hierarchic spatial scales as macro, meso and site. Then we quantitatively analyzed forest structure and the recent state of decline. Macro-scale survey showed that the ratios of tall beech in forests are less than 30 % in number and beech forests were classified into three types. Also beech declines have progressed on ridge lines above 1400 meter elevation and the western parts of Tanzawa as well as northern part of Eastern Tanzawa were not observed significant damage. Forests at high altitudes and flat terrain were suffered more serious decline. Declines also progressed at forests on higher solar radiation and lower soil water index. Field surveys around the top of Mt. Tanzawa and Mt. Hinokiboramaru, where declines are relatively serious, indicated that forest facing south to west suffered serious damage. Also a site scale survey on several specific forests where declines remarkably progressed showed not only massive tall beech damage but also less vigor even for other tall trees. Based on the observational study above mentioned we discussed spatially hierarchic relations of beech decline causes and then sort out research priorities.
