持続可能な林業経営確立のためには林業の採算性を改善することが不可欠である。そのためには立木価格や素材価格の向上は検討しなければならない事項であることから、本研究では木材需要の中で需要量が多く単価も高い用素材価格を取り上げ、1990年代以降を主たる対象として人工乾燥や工場の経営に強く影響する歩留まりとの関係を解明することを目的とした。研究手法としては、まず統計調査データを用いて品価格、素材価格、立木価格の推移や工場を巡る状況の変化を分析した。その結果、1995年以降、プレカット加工率や人工乾燥材率の上昇、品の区分において角類が減少するなどの変化が同時に進行し、歩留まりが顕著に低下していることがわかった。 また、国産材木取り等に関する聞き取り調査を行い、歩留まりが低下している実態を把握した。これらを踏まえて工場経営に及ぼす影響を試算すると、歩留まりが低下すると粗利益が減少すること、工場の付加価値率はほぼ変わらない水準にあることが明らかになった。以上から、歩留まりの低下による粗利益の減少に対応して、素材の仕入れ価格を低下せざるを得ず、これが1995年以降の用素材価格下落の主な原因であると考えられることを指摘した。

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Time efficiency of log-cutting band saw is derived from the same data of analytical investigation of sawing work reported in the previous paper. Results show that;
1) The real working time of the machine is about 80%, of the whole operated time.
2) The time of real cutting, movement of log-setting car, log handling and other working time as against the whole working time are 32, 28, 16 and 6% respectively.
3) The sawing efficiency of the machine expressed by the volume of sawed logs per unit time is 19 koku/hi. in average.

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The purpose of this paper is to reconstruct manufacturing system of Hirakawa Lumbering Factory. It was used in favorable conditions of water power supplying such as “Ide” canal in 1939. There were two floor in the factory, upper floor for lumbering, and down floor for power supplying. The flow line of wooden materials was reconstructed from the remains of lumbering machines. And the power transportation system was revealed from the analysis of machines in down floor. The design of lumbering system was rational, despite the power supply system was complicated. Therefore priority was given to lumbering system in this case.

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In recent years, the felling of Akita-Sugi (Natural Cedar, Cryptomeria japonica) has rapidly decreased in volume of resource diminution, and the sawmill industries located in its area has faced to a serious supply problem.
In this paper, the author analysed the response of sawmill industries in Noshiro and Odate City in the Yoneshiro river basin famous as Akita-Sugi area.
The results are summarized as follows:
1) Akita-Sugi is the best qualified wood for sawmill industry in Japan. It is aged about two hundred years and distributed almost in national forests. The sawmill industry in Akita Prefecture has been priviledged the special sale system by the regional forestry office. Wartime and postwar deforestation of Akita-Sugi brought the rapid decrease of felling in recent years and it will be exhausted in near future.
2) Under these conditions, the sawmill industries in Noshiro and Odate City have responded differently.
a) The sawmill industries in Noshiro have added the processing in higher order such as Harimasa (a kind of hard board) and Meiboku (precious choice wood) production and pushed forward the dependence on imported timber. But such a conversion has brought the class differentiation between large-scale and small-scale factories.
b) The sawmill industries in Odate have little developed recently and the multiproduction is less in percentage than in Noshiro. The supply of timber has moderately changed to the domestic afforested Sugi. Thus a sawn timber market was established in 1973 for the purpose to exploit new consumption for the afforested Sugi.
3) There are two factors for the above different responses. The one is the difference in timber supply, that is, the sawmill industries in Noshiro are more urgent in this problem. The other is the different producing structure, that is, the multi-production is more advanced in Noshiro.

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