Data from: Role of axis reversal from the short-shoot to long-shoot habit for crown maintenance in slow-growing Betula maximowicziana trees

PREMISE OF THE STUDY: Branch growth and its spatial arrangement determine tree crown architecture and leaf display, and thus the productivity of trees. Branch axes elongate by the sequential production of shoots with differing morphology and function, such as short shoots and long shoots. This study investigated ontogenetic changes in axis growth in Betula maximowicziana and quantified the role of axis reversal between the short-shoot and long-shoot habit, particularly reversal from the short-shoot to long-shoot habit. METHODS: From eight trees with varying levels of growth vigor, 716 branch axes forming the basic crown architecture were sampled. Past growth of the branch axes was reconstructed from leaf and bud scale scars, and compared between slow-growing and vigorously growing trees. KEY RESULTS: Branch axes reversed more frequently between the long- and short-shoot habits in slow-growing trees than in vigorously growing trees. Short-shoot-origin axes that reversed to the long-shoot habit lived for longer periods and grew larger than axes that remained in the short-shoot habit. Short-shoot-origin axes reversed as they grew away from branch apices, typically more than 6 years after they had originated. CONCLUSIONS: Reversal of short-shoot-origin axes to the long-shoot habit is an endogenous growth process of trees with reduced vigor. Like epicormic branching, the reversal may contribute to the maintenance of productivity of large old trees by prolonging axis longevity and filling the inner part of the crown. This study presented an ontogenetic change in branch growth, which broadened our perspectives on the growth and survival of long-living trees.R code for GLMMs, Axis reversal in Betula maximowicziana.R source code for GLMM for the probability of lateral axis having reversed.AxisReversal1RcodeGLMM.txtData table of axis fate, Axis reversal in Betula maximowicziana.Data for GLMMs for the probability of lateral axis having reversed.AxisReversal2AxisFateData.txtR code for LMMs, Axis reversal in Betula maximowicziana.R source code for LMM to test the effect of lateral axis type and its location on the growth of lateral axis.AxisReversal3RcodeLMM.txtData table of axis size, Axis reversal in Betula maximowicziana.Data for LMMs to test the effect of axis type and location on the size of axis.AxisReversal4AxisLocGrowthData.tx