On the influence of air pollution on the forest trees (Forestry)

大気汚染が林木(スギ)に及ぼす影響について, 樹葉の分光反射特性を利用した赤外カラー画像のバイバンド比(R/G)を総合的な活力指標として, これに影響を及ぼすと考えられる元素含有量とその分布状態および生長をとりあげて検討した。その結果の概要は次のとおりである。(1)大気汚染度とバイバンド比には相関関係があり, 汚染地区の活力低下が認められた。(2)樹葉に含まれる全硫黄量は汚染度の高い林分ほど多い傾向を示した。(3)重金属(Pb・Cd・Zn)は汚染林分の外皮において高い含有量を示した。これは大部分浮遊ばい塵に含まれた重金属類が付着したものと考えられる。(4)汚染地区林木の内皮におけるカリウム含有量は, 対照地区との比較において著しく低い値を示した。As the synthetical index of the tree vitality, we investigated the infrared bi-band ratio (R/G) of the leave of SUGI (Cryptomeria japonica D. Don), which based on the characteristics of the spectral reflectances, so as to clarify the influence of air pollution on the forest trees. Moreover, we examined some factors, those were supposed to concern the vitality, volume increments, chemical elements, and their distribution. Results were as follows; 1. The bi-band ratio had a positive corelationship between air pollution, and the trees, in the polluted areas, showed the vital decay. 2. Total sulfer contents in the leave also had a positive correlationship between air pollution. 3. High contents of heavy metals (Pb, Cd, Zn) were found at the outer bark of the trees, in the polluted areas. It was assumed that this was caused by the catchement of the floating dust. 4. Potassium contents of the inner bark, in the polluted areas, were lower than the control.departmental bulletin pape