著者

小椋 純一

出版者

国立歴史民俗博物館

雑誌

国立歴史民俗博物館研究報告 (ISSN:02867400)

巻号頁・発行日

vol.171, pp.223-261, 2011-12

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高度経済成長期を契機とする植生景観変化とその背景について,岡山県北部の中国山地(津山市阿波),京都市北部郊外(左京区岩倉付近),伊勢湾口の離島(神島)の3つの地域を例に,写真や文献類,また古老への聞き取りなどをもとに考察した。その結果,岡山県北部の中国山地では,高度経済成長期の頃までは,牛の放牧などのために広い草山が見られるところが何箇所もあったが,高度経済成長期を契機にして,草山は急速になくなっていった。一方,スギやヒノキを中心とした人工林は,高度経済成長期の頃を中心に急増した。また,人工林などに変わることなく残った薪炭林では,その利用がなくなり,近年では樹木の大樹化が進んでいるところが多い。また,京都市北部郊外の里山では,かつてはアカマツ林が広く見られたが,高度経済成長期の頃を境に,林が放置化されて植生の遷移が進み,近年ではマツ枯れによりアカマツ林は大幅に減少してきている。その一方で,シイやカシなどの常緑広葉樹林の割合が増えてきている。また,高度経済成長期の頃までは,さかんに森林が利用されたことにより,さまざまな林齢や樹高の森林が見られたが,近年は森林の樹高などの変化があまりなくなっている。また,伊勢湾口の神島でも,かつてはその山の植生はマツが主体であったが,高度経済成長期の途中から,京都市北部郊外の里山と同様に,マツ林は大幅に減少し,その一方で,近年ではヤブニッケイやカクレミノなどの常緑広葉樹主体の森林が増えてきている。一方,かつては山の南向き斜面を中心に広く見られた段々畑は放置されるところが増え,森林化しつつあるところが多い。このように,高度経済成長期以降の植生景観変化は,地域によりさまざまであるが,いずれの地域でも高度経済成長期の頃の人々のくらしの激変や国の政策などが原因となり,人々の植生への関わり方も大きく変化し,それによって大きな植生景観の変化が生じた。Vegetation changes with the high economic growth period as the turning point and their backgrounds in three regions in Japan were studied based mainly on photos, literatures and interviews of elders. Those three studied regions were mountainous village located in the north of Okayama Prefecture (Aba, Tsuyama City), northern suburb of Kyoto City (Iwakura, Sakyo-ku) and an island in the mouth of Ise bay (Kamishima). Results are as follows.In the mountainous village in northern Okayama Prefecture, broad grassland areas for cattle grazing et cetera were commonly seen until the time of high economic growth. However they have disappeared rapidly since the high economic growth period. On the other hand, plantations of Japanese cedar and Japanese cypress increased rapidly especially in the time of high economic growth. Meanwhile woodland trees once used for firewood and charcoal have usually grown much bigger as they have not been used as fuel since that time.In the hilly and mountainous areas in the northern suburb of Kyoto, Japanese red pine forests were once seen widely. However, they have decreased greatly by pine wilt after the high economic growth period, as the forests were left without use and the plant succession proceeded. On the other hand, evergreen broadleaved trees such as Castanopsis and Quercus have been increasing gradually. And until the time of high economic growth, the forests had a variety of stand age and tree height due to the intense use. However, the variety has been lost greatly in recent years.In the Kamishima island in the mouth of Ise bay, Pinus was once dominant species in the vegetation of the mountain. However, pine trees have decreased greatly, while evergreen broad leaved trees such as Cinnamomum and Dendropanax have increased after the high economic growth period. It is similar to the case of the northern suburb of Kyoto. Meanwhile the terraced fields once widely seen especially on the south-facing slopes of the island have been gradually covered with bushes and trees as they have been abandoned.Thus, although changes in vegetation since the period of high economic growth vary by region, great changes of vegetation have occurred in every region due to the big changes of relationship between man and vegetation which were caused by the rapid changes of people's lives and nation's policy in the time of high economic growth.