関東甲信・関西瀬戸内地方におけるスギの衰退現象

概要

論文の詳細を見る
The relationships between probable causal factors of damage and actual health and damage to Japanese cedar (Cryptomeria japonica D. Don) trees in the Kanto-Koshin and Kansai-Setouchi Districts were studied. The causal factors included the combination of secondary air pollutants with levels of precipitation, and soil condition. Large trees, especially large healthy trees, were fewest in damaged zones coinciding with regions having high concentrations of secondary air pollutants and low levels of precipitation. On the other hand, many large healthy trees were found in zones having low concentrations of secondary air pollutants and either high or low levels of precipitaion. Therefore, we can infer that the low number of large healthy trees in damaged zones is a result of exposure to damaging secondary air pollutants. It was found that the number of damaged trees was not related to the condition of soil surface, represented by the percentage of bare ground compared to the percentage of litter or plant-covered ground under the tree crown. It is generally believed that higher percentages of bare ground causes deterioration of soil conditions (i.e. hardness and soil acidificaton) due to a shortage of nutrient baring compost. However, we found that changes in the percentage of bare ground did not correlated to cedar damage as of the date of this study.
森林立地学会の論文
1990-12-30