Abstract
In this report, the author studied on the applicability of two tree volume tables showing the different type, the standard volume table now in use and ALGAN's table, mainly with the materials on Sugi in _??_ita district.
In order to answer its original purpose of computing the stand volume with no errors, and ease, a tree volume table must posess both of the following items:
(a) A volume table itself is accurate.
(b) The elements can be measured and computed plainly and correctly. After examining under such items, the results were led as follows:
(1) Upon test of the two tables, it is admitted that the standard volume table itself has not any significance, but the other has (See Table 1 & 2).
(2) With the elements containing no errors, however, the error of stand volume estimated by means of ALGAN'S table is small to our satisfaction as well as by means of standard volume table, which is due to the nature of an error that belongs to ALGAN'S table in itself (See Table 3).
(3) There are two practical procedures to obtain the average height of trees in each diameter class; eye-measurement and freehand curve, and hypsometer measurement and curve of regression equation. While with the former, the error of stand volume estimated by means of the standard volume table is fairly small, with the latter it is too large (See Table 4).
(4) Whichever we may take of the two ways to decide the series number, the error of stand volume estimated by use of ALGAN'S table is not so large as that in the latter occasion above mentioned (See Table 4 & 5).
Consequently it follows that the only method to make the error of estimated stand volume small enough to be put to practice is to compute it taking the standard volume table with heights decided by employment of a hypsometer and a equation of height over diameter curve. In actual practice, however, it is very difficult to know heights by such means, and so the standard volume table cannot be concluded to be of good utility. If the curves of volume over diameter in each stand somewhat keep going side by side as learned slightly in Table 2 and if the method to get the series number more correctly and easily can be found, the new unsignificant volume table having such a type as ALGAN'S table may be more applicable than the standard volume table.
