|Budget Amount *help
¥1,700,000 (Direct Cost : ¥1,700,000)
Fiscal Year 1994 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1993 : ¥1,200,000 (Direct Cost : ¥1,200,000)
The wave regenerated forest in the White Face Mountain region of U.S.A., reported by Spurgel, corresponds to the forest which is known as "Shimagare" type forest in Japan. There are a lot of researches on this wave regenerated forest but very few on the snow season condition of the wave regenerated forest. kitai and Maeda once reported that snow had collapsed part of the structure of wave regenerated forest on Kita-Yatsugatake Mountain, from where the death of trees had begun. Since then, the structure of the wave generated forest has been continuing to experience a gradual change due to the influence of snow. We, therefore, researched the current forest condition and found out that the zone previously comprised of young trees around 1980 has now changed into the mature-tree zone and that the previous seedlings zone turned into the young-tree zone. On the windward side of the current young-tree zone where the snow is heaviest, there were snowdrifts piled up, from where a new canopy ope
ning was found to be developing. Moreover, trees around the canopy opening started to be withered.
It can be said that this phenomenon of withering is largely caused by the wind impact, but it is necessary to know the water flux in a tree in order to explain the withering and damaging process of the tree due to the wind impact. This called our attention to the water content in leaves of a tree to be used as an index for the withering/damaging stage. Accordingly, to clarify its effect on the above-mentioned process of a tree, we examined a seasonal change of the water content in needle leaves of an Abies-veitchii tree or the relation between the water content in needle leaves and the withering process of the corresponding trees in the wave regenerated forest. This examination proved that the water content in needle leaves in the wind-impacted area increases from September to November and gradually decreases during the subsequent winter. Also, we examined the water content according to our classification by the discoloration of leaves, which allows the visual check on the withering stage of a needle leaf. And this showed that the water content in leaves of a tree can be excellent aids in indicating the withering process of the forest trees.
In addition, by using the differential scanning calorimeter to measure the endothermic reaction of the water content in a needle leaf, we obtained a result indicating that the water content in leaves can reflect the slightest withering level. This result suggests that the above-stated approach - the one with the water content in leaves of a tree - can be used effectively as an index for the withering status of the forest trees. It is necessary, hereafter, to advance a further explanation as to the withering process of the forest trees in this approach or something similar thereto. Less