Respiration rates predict differences in growth of coast redwood

The relation between growth rate traits (height, basal diameter, stem volume and branch diameter) and two measures of respiration rate [metabolic heat rate (q) and CO2 production rate (Rco2)] and their ratio (q/Rco2) was examined on a collection of 192 different genotypes of coast redwoods [Sequoia sempervirens (D.Don) Endl.]. Branch diameter was not correlated with any of the respiratory measures, but the other three growth traits gave highly significant (P < 0.001) correlations with positive slopes. Combining the four growth traits and the three respiratory variables (q, RCo2 and q/Rco2) to give two canonical variates, one representing growth and one representing respiration, gives an even stronger linear correlation (r= 0–85). These data suggest that simultaneous assay of multiple respiratory measures on juvenile trees can be used to predict their longer-term growth rates.