In the forest inventory for stand growing stock estimation, stand increment prediction and other purposes, the precision of estimation and prediction and the appropriateness of the management planning made on the basis of the mentioned estimated and predicted values, are largely affected by the fitness of applied volume table to the condition of observed stand. In order to prepared volume tables which are fitting well to the condition of stand in a given region, in a given district or in a given forest area, a great numbers of local volume tables are needed. However, for the preparation of volume table, enormous data are needed and many time, cost and effort must be spent for the data collection and analysis both. Therefore, volume tables are, in general, prepared for a large region. Accordingly, in the application of volume tables the fitness of table to the condition of a given stand is necessary to be tested in advance. This study aims to examine the appropriateness of volume tables for Pinus elliottii and Pinus patulu. 40 of Pinus elliottii (with bark and without bark volumes) from Águas de Santa Bárbara state forest in São Paulo region and 42 trees of Pinus elliottii and 27 trees of Pinus patula (both with bark volumes) from Campos do Jordão state forest has been selected and measured. The conformity of measured volume to the corresponding values presented in volume table are tested on the basis of t-test. The results are presented in Table 5 and Figs. 4-6. The values those presented in Tabela-1 and Tabela-2 which are corresponding to Pinus elliottii in Águas de Santa Barbara state forest, and in Tabela-2 and Tabela-43 which are corresponding to Pinus elliottii and Pinus patula of Campos do Jordão state forest, respectively, are significantly different from those shown by Volume Table-A and Volume Table-B. This means that the measurement volumes do not fit well to those values presented in volume tables. Therefore, the regression equations those express the relationships between actual volumes and the values in volume table were analyzed. The results are presented in Table 6 and the values adjusted on the basis of the above mentioned relationships are given in Table 7. By this method, the values in a not appropriate volume table is adjusted and made to be closely agree to the actual volume of observed stand.
森林蓄積の推定や林分生長量の予測,その他の森林調査を行なう場合,使用する材積表(立木幹材積表)がその林分に適合しているかどうかは,その推定精度や予測結果等に大きく影響する.材積表は地方や地域,地区等の小範囲を対象に調製された,いわゆるlocal volume tableが適合性は高い.しかし材積表は膨大なデータの収集とその分析検討および重回帰式による材積式の計算や材積表の調製等,多くの時間や労力,経費等を必要とする.そのため一般には材積表は広い範囲を対象に調製されるケースが多い.したがって使用する材積表はその適合度を事前に検定しておくことが望ましい.本研究はサンパウロ州Águas de Santa Bárbara州有林のPinus elliottii 40本(with bark, without bark)およびCampos do Jordão州有林のPinus elliottii 42本,Pinus patula 27本(何れもwith bark)を対象に標本木の実測材積を求め,これとそれぞれにおいて使用される材積表材積との対応による適合度の検定をt検定により試みた.その結果はTable5およびFig.4-Fig.6に示すとおりとなった.すなわちÁguas de Santa Bárbara州有林におけるPinus elliottiiのTabela-1,Tabela-2,およびCampos do Jordão州有林におけるPinus elliottiiのTabela-2,Pinus patulaのTabela-43,材積表-A,材積表-Bで有意差を示し,材積表材積は実測材積と適合しなかった.そのためTable6に示すとおり実測材積と材積表材積の回帰式を計算し,これにもとづいてTable7のように材積表材積の修正表を示した.これにより適合しなかった材積表材積は調査対象林分の材積の真値に近似的に修正されることになる.