森林立地学会誌 森林立地50 (1), 2008, 41〜49
Jpn.J.For.Environment 50(1), 41−49 2008
明治初期に成立した佐渡御料林の台帳に記載されている等級区分と土壌タイプ
斉藤昌宏
三重大学
明治時代初期に成立した佐渡の御料林は林分数420箇所，面積6,750haを占め，1989年から37年間存続した。その構成は一等林が12箇所（水源林１箇所を含む）であり，多くはアカマツ林で土壌は”壌土”であった。二等林は30箇所でアカマツ林が多いがスギ林，雑木林，竹林も含まれていた。土壌の多くは赤壌，黒壌などの壌土グループと燥埴，壌埴などの埴土グループに区分されていた。三等林は164箇所であり，ナラ林，雑木林の割合が高かった。土壌は石礫，岩石などに区分されている例が多く，立木密度も低いため，材の生産はあまり期待できなかったと推測される。その外に面積が小さい員外林，風致林が多数含まれていた。台帳を作成するための林分調査は1880年代から行われ，1876（明治9）年に制定された官林調査仮条例に従って行われたと判断された。土壌は”?土”，”埴土”，”壌土”，”砂土”，”石礫”，”岩石（地）”の主要な６タイプに分けられ，埴土と壌土は色合いや乾燥度によってさらに細分されていた。当時としては最新の技術によって調査が行われていることから，地元の技術者と中央から派遣された技術者のグループがこれらの調査を実施したと推察された。
Masahiro
Saito,： Stand
evaluation and soil types in forest registers of the Crown Forests in Sado
Island.
Crown forests in Sado Island, since
1889 to 1925, consisted of 420 forest lots with 6,750 ha in the area. As a result of the analysis on
the forest registers which ware made about 120 years ago, classification
methods of forest stands and soil types became clear. The forests were grouped into five classes, such as
first class, second class, third class, small forest and felling prohibition
forest. Almost of the twelve
forest stands belonged to the first class, were pine （Pinus thunbergii）forests, and soils under the stands were
classified to "loam group". There were one Cryptomeria stand, one Quercus
stand and few mixed stands in the second class forests. The others in the second class were
also pine stands and the soils were estimated mainly to "loam group"
and "clay group". Lots
of forest stand in the third class were coppice forests or poor, sparse
forests, so it was not possible to expect the much income from the
forests. It seemed to carry out
the evaluation according to "a tentative regulation on the survey for
national forest" which was established 1876. Soil types were classified into six main groups as
"humus soil", "clay", "loam", "sand",
"rubble land" and "litho-soil". "Clay" and
"loam" were subdivided on their color or dryness. It was estimated that the soil
survey was carried out on the basis of a latest knowledge in those days. Therefore, it can be guessed that few
engineers who were trained by the central government did initiative of the
survey group for the forest registration.