Knightia excelsa / Height

Knightia excelsa, NZ, height from RCD (Table 3)

HeightKnightia excelsa · ProteaceaeNew ZealandplantationRead from the original paper

Equation

As printed (Table 3, Height, Knightia excelsa)

y = 0.0513x

In this library's units, ready to compute (m)

Height = 0.513 * DRC

DRC: Root collar / stem base diameter, cm

Open-spaced juvenile plants (2-year-old containerised plants on-grown for 3 years, sampled up to 5 years). The tables are headed 'at age 5 years' but the appendix figures show points from all harvest years, and the paper gives no n or RCD range for these fits, so none is recorded. x is root collar diameter in mm; biomass in g and height in m (units inferred from Table 2 and Appendix 1 means, which the equations reproduce; the paper does not print units beside the equations).

Source

Marden, M., Mason, N. W. H., Lambie, S., & Rowan, D. (2025). Total plant biomass, carbon stock, and species- and age-specific allometry for 12 of New Zealand's early-colonising indigenous shrub and tree species to 5 years of age. New Zealand Journal of Forestry Science, 55, 3.

doi:10.33494/nzjfs552025x387x · Open access · copy we read

0.936

R² · Table 3, Height, Knightia excelsa, r² column

R²: 0.936
Method: ordinary least squares, linear through origin (y = mx)
Where: Taruheru River terrace, Gisborne, New Zealand
Last checked: 2026-11-02

Calculate

Root collar diameter (cm)

1.03

Height (m)

Checks this equation passes

On every build, the library's form and the paper's own form (in its units) must both give these values within 1%.

Inputs	Expected	We get	From
DRC = 2	1.03	1.03	Computed from the printed form hand-computed from the published form (RCD in mm, mass in g, converted)
DRC = 6	3.08	3.08	Computed from the printed form hand-computed from the published form (RCD in mm, mass in g, converted)
DRC = 15	7.7	7.7	Computed from the printed form hand-computed from the published form (RCD in mm, mass in g, converted)

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Knightia excelsa, NZ, height from RCD (Table 3)

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