Vegetation history in Ohsado Mountains at Sado Island

Research Project

Project/Area Number	03660149
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	林学
Research Institution	Niigata University
Principal Investigator	NAKATA Makoto Niigata Univ., Fac. of Agriculture, Assistant, 農学部, 助手 (80217744)
Co-Investigator(Kenkyū-buntansha)	UCHIYAMA Takashi Chiba Keizai Coll., Fac. of Elementary Education, Assoc. Professor, 短期大学部・初等教育科, 助教授 KAMITANI Tomohiko Niigata Univ., Fac. of Agriculture, Assoc. Professor, 農学部, 助教授 (40152855)
Project Period (FY)	1991 – 1993
Project Status	Completed (Fiscal Year 1993)
Budget Amount *help	¥2,300,000 (Direct Cost: ¥2,300,000) Fiscal Year 1993: ¥400,000 (Direct Cost: ¥400,000) Fiscal Year 1992: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1991: ¥1,400,000 (Direct Cost: ¥1,400,000)
Keywords	Ohsado Mountains / Cryptomeria japonica forest / Thujopsis dolabrata var. hondae forests / Fagus crenata forest / Forest environment / Soil chemistry / Forest structure / Pollen analysis / 土壌特性 / ポドゾル / 天然スギ / 更新様式 / 崩壊斜面 / シナノキ林 / 実生 / 萌芽 / 植生 / 土壌 / 立木位置図
Research Abstract	In Ohsado Mountains, Cryptomeria japonica forests distributed upper than ca.700m on clayy soil materials, where air humidity and soil moisture were very high. Wet iron podzols or Dry podzols were formed at the forests. Whereas, Thujopsis dolabrata var. hondae forests distributed lower than ca.700m on relativery sandy and dry soil materials, where air humidity was rather low. Dry slightly pozolic soils were formed at the forests. Fagus crenata forests distributed at high altitudes of Mt. Kinpoku, where air humidity was intermediate between former two forest types. High altitude types of Brown forest soils were formed at the forests. The degree of podzolization and soil chemical properties of upper horizons showed clear differences among these three forest types. In the mixed forest consisted of Cryptomeria japonica and deciduous tree species, large-sized investigation plot was set up on the west slope of Mt. Bunagahira, where location, sizes and crown structure of all trees including dead or cut stumps were measured. Quercus mongolica var. grosseserrata grew near the cut stumps of Cryptomeria japonica. Formely, several tree species such as Cryptomeria japonica or Acer mono were cut down for the man's benefit in Osado Mountains. Therefore, present forest structure was storongly affected by past man's activities. Pollen analysis was carried out using samples collected from three different sites in Ohsado regions. One of them was a forested site consisted of Cryptomeria japonica, where Ericaceae shrubs and ferns dominated about 200 or 250 years ago. From the sample collected at Kuninaka Plain, vegetation changes of last 1500 years were showed.