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 (R(CO2))] and their ratio (q/R(CO2)) 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, R(CO2) and q/R(CO2)) 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.