Establishment-year height growth in hybrid poplars; relations with longer-term growth

Abstract

We examined the potential for using components of establishment-year height growth in predicting longer-term growth rankings of six hybrids of Populus deltoides × nigra and one of P. nigra × maximowiczii. Height rankings at the end of the establishment year were correlated (P ≤ 0.10) amongst the four field trials and were generally stable from 38 days after planting onward. End-of-season height rankings from field trials and a controlled environment trial were weakly correlated. Height rankings at the end of the first year did not correlate with rankings at the end of the fifth year, correlations with fifth-year ranks did improve in the second and third years. Shifts in clonal rankings after the establishment year may have been associated with (1) a decreased influence of the planted cutting on growth after the establishment year (2) clonal differences in the time of budburst which were minimized at the time of planting (3) clonal differences in late-season photosynthate allocation to roots (4) clonal differences in branching patterns and canopy development after the establishment year.