Abstract

WABO, E.; CELLINI, J. M.; MARTINEZ PASTUR, G.  and  LENCINAS, M. V.. Comparison between the relative accuracy of the tree caliper and the diameter tape in the measurement of dbh, basal area and tree volume. Quebracho (Santiago del Estero) [online]. 2007, n.14, pp.5-14. ISSN 0328-0543.

The study compare the relative accuracy of DBH measured with caliper and diameter tape. Four diameters were measured with the caliper in each normal cross section: that corresponding to only one diameter with the beam oriented to the center of the plot, those corresponding to the arithmetic and geometric means of two diameters measured perpendicular to each other, and the arithmetic mean of three diameters. From these five DBH the basal area and the volume was calculated for each sample tree. With these values the corresponding basal area and volume density per hectare was determined. The arithmetic mean of the two diameters measured perpendicular to each other was considered as the reference DBH, and so was with the basal area and volume associated. The study was made with trees of Nothofagus pumilio growing in the native forests of Tierra del Fuego (Argentina). At the tree level, the values for DBH, basal area, and volume determined with the tree caliper showed differences lower than 0.5% against the control; the same parameters exhibit differences between 3% and 4% when compared with the diametric tape. At hectare level, the results showed the same differences being no higher than 0.4% when the caliper was used, and between 3% and 4% when determined using the tape. The lowest values were those corresponding to the geometric mean of two perpendicular diameters while the highest to those obtained out of the tape. No differences among the determination of DBH, basal area and volume obtained from a single reading using caliper and from the arithmetic average of two perpendicular diameters were observed both at tree and area level.

Keywords : DBH measurement; Forest inventory; Nothofagus pumilio; Tierra del Fuego.

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