Early patterns of flowering, winter injury, and flushing of red maple progenies grown in five locations

Abstract

Red maple (A. rubrum L.) seedlings grown from seed collected from throughout the species'' natural range were planted in 5 [USA] states: Ohio, Michigan, Indiana, Wisconsin and Minnesota. Flowering was almost exclusively dioecious and commenced in certain precocious progenies in the Ohio plantation 3 yr after seed germination. Significant differences were found in all plantations among 7- and 8-yr-old progenies in percentage of trees with flowers. Three plantations had differences in the number of flower buds per flowering tree and percentage of trees with winter injury. Variation among seedlots was apparent for length of the terminal leader injured by cold at 2 sites and for earliness of flushing in all plantations where recorded. Frequency of winter injury and time of budbreak of progenies showed a close relationship to geographic and climatic variables of seed sources, with northernmost progenies being less frequently injured and beginning growth first. There was also consistent progeny response between plantations in these 2 traits. Progeny from high elevations in the central and southern regions had less winter injury than progeny from low elevations. Flushing occurred in the seed lot sequence of northernmost origin first, southern next, and midlatitude last. Correlations of flowering frequency of progenies common to several plantations were in many cases significant, but correlations between plantations for numbers of flowers (per flowering tree) were less often significant.