9. 西八木層出土木材の樹種（前篇 発掘調査の成果 / 第Ⅱ部 古環境の復元）

The Nishiyagi Formation is distributed at Akashi district of Hyogo Prefecture, and it is regarded as deposits of the last interglacial epoch, the Shimosueyoshi age. 146 specimens of fossil wood were excavated from a cliff of the lower two members of the Nishiyagi Formation in 1985, and were identified in the present paper. Furthermore, specimens which has been excavated from the comparable strata with the Nishiyagi Formation near the cliff in 1948 and preliminary identified by Watari Shunji are also reidentified here. Some of the specimens excavated in 1948, however, are sometimes regarded as those were not derived from the Nishiyagi Formation but from an older stratum of the Lower Pleistocene.Totally 306 specimens were identified into 33 taxa of 18 families as shown in Table 8. Ecological habitats of those taxa are quite wide in range from the subarctic to the subtropical climate, and it is considered the fossil wood does not indicate a single vegetation but indicates several vegetations of a single age or of several ages. Although most of the identified taxa are still now distributed in Japan, some trees which has been already extinct from Japan or Honshu Island, for example, Metasequoia, Cudrania and Lagerstroemia, are included. The extinction of the latter two taxa in the last glacial age is presumed here, while it is generally considered that Metasequoia has been already extincted in Japan before the last interglacial age

現生のウルシの成長解析からみた下宅部遺跡におけるウルシとクリの資源管理

下宅部遺跡から出土した縄文時代中期中葉から晩期中葉の木材を対象として，ウルシとクリの資源管理について検討した。下宅部遺跡出土木材の直径分布と成長輪数の解析により，クリとウルシは，現在の薪炭林やウルシ林とは異なり，多様な太さと年齢の個体が生育する柔軟な管理がなされていたと指摘されていた。本論では，当時のウルシ木材の直径成長を解析し，これを現在植栽されているウルシの成長と比較し，縄文時代のウルシとクリを中心とした森林資源管理を検討した。その結果，ウルシとクリは，直径6～8cmで8年生未満の個体を丸木として主に利用する一方で，それ以上の大きさの個体も適宜割って活用しており，多様に利用されていた。他の樹種は，細く若い木を丸木で使うものと，太く年のいった木を割って使うものに分かれていた。現生のウルシの成長と比較すると，縄文時代のウルシは成長が遅く，ほぼクリと同様で，当時は現在のウルシ畑よりも密に生えていたと推定された。下宅部遺跡のクリとウルシの成長は，新潟県青田遺跡の晩期末葉の柱材に使われているクリよりも遅く，現在の青森県田子町の萌芽によって再生した二次林のクリとほぼ同等であった。下宅部遺跡のごく近くにあったと考えられるクリ林とウルシ林の周辺には二次林と自然林があり，その成長は二次林，自然林の順で遅くなる傾向が確かめられた。We clarified the management of Castanea crenata and Toxicodenron vernicifluum resources at the Shimo-yakebe site, Tokyo, from excavated wood remains. At this site, an analysis of diameter and growth rings of these species indicated, differing from the present management, an existence of heterogenous forests consisting of trees with diverse size and age. In this paper, to clarify the forest management during the Jomon period, growth trends in both species were compared with those of extant trees. In both species, trees less than 6–8 cm in diameter and 8 years in age were mainly used entirely, but logs of larger trees were also used as split timber for various uses. Trees of the other taxa were either used entirely or as split wood depending on the taxa. Among Toxicodenron vernicifluum trees, no correlation existed between the existence of scars left by putative lacquer collection on the stem surface and their use. Toxicodenron vernicifluum trees at the Shimo-yakabe site grew as fast as Castanea crenata trees, but more slowly than extant trees that are planted with ample space in between to allow fast growth till the collection of lacquer in 10 to 15 years. Trees of Toxicodenron vernicifluum and Castanea crenata at the Shimo-yakabe site grew more slowly than Castanea crenata trees used for pillars at the Aota site, Niigata, but as fast as the present secondary growth of Castanea crenata trees from stem sprouts in Aomori. A growth analysis at the Shimo-yakabe site revealed that these Toxicodenron vernicifluum and Castanea crenata forests were surrounded by a more slowly growing, secondary forest and a slowest growing, virgin forest.一部非公開情報あ

遺跡出土植物遺体からみた縄文時代の森林資源利用

本論では，1980年代以降に行われた低湿地遺跡の発掘調査の成果をもとに，木材と種実遺体を中心として植物利用に関する研究成果を総覧し，縄文時代における森林および植物資源の管理と利用を概観する。この約30年の研究によって，縄文時代の人々は単なる狩猟・採集民ではなく，少なくとも前期以降の東日本を中心とした10年以上定住した集落では，クリとウルシを中心として，集落周辺の森林資源を管理して利用していたことが明らかとなった。クリが選択されて利用されたのは果実と木材が有用で活用しやすいためだけでなく，クリの木が石斧を利用する当時の伐採技術に適していたという面でも選択されていた。ウルシの樹液を用いた漆器の製作と木材の利用は，前期以降，東日本を中心とする地域には普遍的に認められ，木と技術が前期以前に中国大陸からもたらされたことを示唆している。縄文時代の人々は，中期頃以降，クリやウルシの利用に加えて，アク抜きが難しいトチノキを加工する技術を獲得し，これを水辺の施設で加工して利用することで，より重層化した植物資源利用を行っていた。中期頃には有用な品種の選抜も行われるようになり，クリやマメ類（アズキ亜属，ダイズ属）では，現在の栽培品種に匹敵する大きさの種子をつけるものも利用されていた。早期でも，類例はわずかであるが，植物性素材の選択は明瞭に行われており，また日本列島外から植物が移入されていたことが明らかとなっている。九州地方では，編組製品の素材の選択が早期に確立されており，後期までは引き継がれていた。最後に，総括として，東日本を中心とした地域における森林資源の管理と利用の様相を集落の立地との関連で復元し，西日本を中心とした地域における森林資源管理と比較して考察した。Human interaction with plant resources in prehistoric periods has been clarified dramatically in Japan during the last thirty years. Here, we review the recent research results carried out in Japan on the use of various plant materials by Jomon people, including timber, fruits, seeds, tubers, fibers, and lacquer and touch upon the introduction of plants from adjacent areas. We have found that the people of the Jomon period were not plain hunter-gathers, but managed and used plant resources around their settlements cleverly. The management of forest resources started at ca. 7000 years ago at the beginning of the early Jomon period, when dominant use of chestnut (Castanea crenata) and lacquer (Toxicodendron vernicifluum) trees as food, timber, and paint resources began. The preference for the chestnut tree accorded with the technical requirement of this stone-age period, and the established use of the lacquer tree and its lacquer of this period indicated introduction of the tree and lacquer technique from China before this period. The management of plant resources became more multilayered in later Jomon periods with the invention of a complex processing method of horse chestnut (Aesculus turbinata) seeds having both tannin and saponin and the construction of wooden structures for such processing around settlements. Seed and fruit remains indicate that this management of plant resources included selection for useful traits and cultivation of useful strains, resulting in the production of some forms of cultigens in chestnuts, azuki beans (Vigna angularis), and soybeans (Glycine max). Occasional finds of plant use before ca. 7000 years ago indicate that people already used plant materials selectively and introduced plants from the Asian continent. In Kyushu selection of basket materials was established at least ca. 8000 years ago, and this selection was maintained through the Jomon period.一部非公開情報あ

化石種ヒメハリゲヤキの材化石の新産地

[短報] Short communicatio

東ネパールにおけるTetracentron sinenseの分布

[論文] Articl

[論文] 縄文時代の日本列島におけるウルシとクリの植栽と利用

この30年間に行われた植物考古学の研究から，約7000年前にはじまる縄文時代前期以降，本州の中央部から東北部では，人々は集落周辺の植物資源を管理して利用していたことが示されている。この植物資源管理は日本列島に在来のクリと中国大陸から移入されたウルシを中心として行われ，縄文時代の人々は植物資源を管理するとともに，クリの果実と木材を，またウルシの漆液と木材，果実を集落周辺で活用していた。しかしこの2種の植物遺体の出土状況は大きく異なっている。縄文時代の遺跡出土木材では，クリは本州中部から東北部および北海道西南部の406遺跡から出土しているのに対し，ウルシは本州中部から東北部の35遺跡から出土しているにすぎない。また両種が出土している遺跡で，花粉と木材の出土量を比較すると，クリの植物遺体はウルシの植物遺体の10～100倍ほど出土している。縄文時代の漆器の出土状況から考えると，本州の中央部から東北部では普通にウルシ林が維持されていたと考えられるのに，なぜウルシとクリに出土状況の違いが生じるのかを下記の三つの仮説をもとに検討した。第一の仮説は，クリに比べてウルシが植栽される集落が限定的なので，ウルシの植物遺体の検出例が少ないという考えである。第二の仮説は，クリに比べてウルシの植栽地が内陸側に位置していて，植物遺体が埋積する低地から遠いために，植物遺体として残りにくいという考えである。第三の仮説は，縄文時代の集落周辺にはウルシ資源よりもクリ資源のほうが多く維持されていたために，クリの植物遺体に比べてウルシの植物遺体の検出率が低いという考えである。検討の結果，第二の仮説がもっとも支持されたが，集落を地域規模で比較する場合には，第一の仮説も意味を持つことが明らかになった。Archaeobotanical studies carried out in Japan during the last thirty years have shown that, at least in central to northeastern Honshu, people carried out a sophisticated management of plant resources around their settlements since the early Jomon period starting at ca. 7000 years ago. This management system was centered on a native chestnut species, Castanea crenata, and an introduced lacquer tree, Toxicodendron vernicifluum, and people used the fruits and wood of chestnut trees and the lacquer, fruits, and wood of lacquer trees extensively by maintaining their resources around their settlements. However, plant remains of these two species occur quite differently around Jomon sites. Wood remains of chestnut trees occur commonly from central to northeastern Honshu to southwestern Hokkaido at 406 sites, whereas those of lacquer trees occur sparingly in central to northeastern Honshu at 35 sites. At respective sites where both trees occur, wood remains and pollen of chestnut trees usually occur 10 to 100 times as common as those of lacquer trees. To examine reasons for this discrepancy in the occurrences of these two trees at Jomon sites in spite of the common occurrence of lacquerware in central to northeastern Honshu, three hypotheses were tested. The first hypothesis postulated that settlements with lacquer tree plantations were far fewer than those with chestnut tree plantations during the Jomon period. The second hypothesis postulated that the more inland location of lacquer tree plantations than that of chestnut tree plantations, that was away from the depositional sites of plant remains, hindered the preservation of lacquer tree remains and the detection of the existence of lacquer trees around Jomon settlements. The third hypothesis postulated that the amount of lacquer tree resources was usually far less than that of chestnut trees at usual Jomon settlements. The analysis supported the second hypothesis most positively, but the first hypothesis also had some importance in relation to settlement characteristics at the regional level