Changes in stem respiration rate during cambial reactivation can be used to refine estimates of growth and maintenance respiration

Summary•  To determine if stem respiration ( r ) varied during cambial reactivation, r was measured during March–July in untreated trees and seedlings, debudded seedlings and girdled seedlings of white ash ( Fraxinus americana ), red maple ( Acer rubrum ) and balsam fir ( Abies balsamea ). •  The r was measured using an infrared gas‐analysis system. Cambial reactivation was monitored by light microscopy. •  After increasing modestly about the time of cambial cell swelling, r declined to a minimum for several weeks and then increased markedly as rapid xylem production (XP) began. Growth respiration ( R g ) over the experimental period was positively correlated with XP over the same time span, with differences in wood anatomy and XP‐measurement method accounting for differences among species. A weak, positive trend was observed between maintenance respiration ( R m ) and XP. R m varied among species. •  The marked springtime increase in r is a nondestructive marker for the onset of rapid XP. Measurements of r made after cambial cell swelling and before rapid XP are appropriate for applying the mature‐tissue method to estimate R g and R m . R g reflects XP, particularly the width of differentiating xylem.