where yijk is the value of the kth tree of the ith provenance and
jth stratum, u is the overall mean, Pi is the fixed effect of provenance
i, Sj is the fixed effect of stratum j, PSij is the interaction between
Pi and Sj, and eijk is the residual. Least-square means for all
traits were estimated using Proc GLM. Note that here and elsewhere
in the text, except where otherwise indicated, the term significant
refers to P < 0.10.