Patterns of Root Production and Mortality during Transplant Establishment of Landscape-sized

Root system regeneration after transplanting of large trees is key to successful establishment, yet the influences of different production systems and transplant timing on root growth remain poorly understood. Patterns of new root production and mortality were therefore measured for 1 year after transplanting landscape-sized Acer saccharum Marsh. (sugar maple). Trees were transplanted into root observation chambers (rhizotrons) from two production systems, balled-and-burlapped (B&B) and pot-in-pot (PIP), in November, December, March, April, and July and compared with non-transplanted trees. Although root production stopped in midwinter in all transplants and non-transplanted field-grown trees, slight wintertime root production was observed in non-transplanted PIP trees. Root mortality occurred year-round in all treatments with highest mortality in winter in the transplanted trees and spring and summer in the non-transplanted trees. Non-transplanted PIP trees had significantly greater standing root length, annual production, and mortality than non-transplanted field and transplanted PIP trees. For B&B trees, greatest standing length, production, and mortality occurred in the April transplant treatment. Production and mortality were roughly equal for non-transplanted trees, but production dominated early dynamics of transplanted trees. Overall, increases in root length occurred in all treatments, but the magnitude and timing of root activity were influenced by both production system and timing of transplant.