胸高断面積の括約誤差について

概要

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Writing the "reading" in a calliper or measuding-tape as the approximate value due to rounding and estimating a basal area (at breast-height) or gathered one, we can consider that the relative error of the estimate value caused by rounding is less than |Ph| or |Ph'| in the following formulas.On single tree i) by calliper|Ph|=(12h)/(√<48n>・m)Ph : Relative error n : The number of diameter measured m : The average diameter at breast-height from n diametrs h : Interval of rounding in the same unit as m' s ii) by tape|Ph'|=(12h)/(√<48> l) l : Circumference Fig. 1 or 2 shows the relation between |Ph|×100 and m or l in i) and ii) respectively. On stand i) by calliper |Ph'|=(12h)/(√<48nr>・m^^-)r : The number of tree in stand m^^- : 1/rΣ^^r__<i=1>ml ii) by tape |Ph'|=(12h)/(√<48r>・l^^-)l^^- : 1/rΣ^^r__<i=1>li According to those formulas, we can consider that, on stand where r is large, the relative error is comparatively small even though the interval of rounding is large.Practicaly we can make the absolute value of relative error less than certain percentage by means of deciding h or n in above-mentioned formulas.
一般社団法人日本森林学会の論文
1953-05-25