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New Zealand Journal of Forestry Science

Table 2 Summary of fixed and random effects used in models predicting mean MOE

From: Validation of models predicting modulus of elasticity in Douglas-fir trees, boles, and logs

Model level

Fixed effects

Random effectsa

Tree

V 2, D, H, T, ρ, A, E

Site/plot

Bole

V 2, D, H, T, ρ, A, E

Site/plot

Log

V 2, D, H, T, ρ, A, E

Site/plot/tree

  1. V = acoustic velocity (time-of-flight for trees, resonance for boles and logs, km s−1); D = diameter (breast-height for trees, at base for bole and logs, cm); ρ = mean weighted green wood density (kg m−3); A = age (harvest age for trees, ring counts for boles and logs, years); H = height (total height of trees, or length of boles (m), or relative height of log in tree); T = taper (i.e. D/H, cm m−1); E = acoustic MOE (i.e. V 2.ρ, following Eq. 1)
  2. a w/x/z = z nested within x within w
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