タクバツ ホウシキ ニヨル シラカシ シンタンリン ノ セイサン キコウ ニ カンスル ケンキュウ ダイ5ホウ シモヤマサ ダイ2 コテイ シケンチ ニオケル タクバツ シケン ホウホウ ト リンブン ノ セイチョウ ニツイテ
Studies on the Productive Structure of "Shirakashi" (Cyclobalanopsis Myrsinaefolia Oerst.) Coppice-Forests Managed by Selection Method(5) : On the Experiment of Selection Cutting and the Growth at the Shimoyamasa No.2 Permanent Plot
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In July 1960, the author settled No. 2 permanent plot (area 173m^2) of Shirakashi (Cyclobalanopsis myrsinaefolia Oerst.) coppice forest managed by selection method at Shimoyamasa, Hirose cho, Shimane Prefecture.
He has researched the condition (especially volume growth) of the stand in November 1962.
The result were as follows :
1 . Percentage of trees to be cut was 56.8% and the choice of Cutting trees was as follows.
Dominant class (D.b.h. 13 cm and over) : All trees were cut.
Middle class (D.b.h. 7-12 cm) : Good trees 75% of this class were reserved, and pooror injured trees was removed.
Over-topped class (D.b.h. 6 cm and under) : Only injured trees were removed.
2. The treatment of this coppice stand was shown by Meyer's formula :
before cutting N=2508・e^<-0.2294・D>
after cutting N=3540・e^<-0.3329・D>
On the other hand, the change process of structure of the stand by the statistic of the diameter distribution.
│ mean D. b. h. │ variance of D.b.h. │ coefficient of variation of D.b.h.
before cutting │ 3.51 cm │ 11.938 │ 98.4%
after cutting │ 2.81 cm │ 5.847 │ 84.3%
3. After cutting, the sprouts reproduced at almost every stumps, and he succeeded in the regeneration.
4. The current annual volum increase of this plot amounted 12.8 m^3 per ha (rate of increment was about 21.8%) from the inventory data. The continuous the net increase are wonderful amounts in the growth of coppice forest at the district.
5. The growth of middle class survivors of which 75% were reserved to 69% the whole growth of the stand (shown schematicalley in Table 12).
The Shimane Agricultural College