COMPARISON OF SEASONAL ROOT GROWTH POTENTIAL OF 1-0 AND 2-0 EASTERN WHITE PINE SEEDLINGS
1-0 and 2-0 eastern white pine ( Pinus strobus L.) seedlings were hand lifted on ten occasions from the Virginia Division of Forestry's Augusta nursery between October 15, 1985 and April 21, 1986. Following lifting, seedlings were subjected to a 21 day hydroponic Root Growth Potential (RGP) test. The two age classes showed significant differences in their pattern of RGP development and magnitude of new root production throughout the time period studied. The 2-0 stock showed a late autumn low that slowly increased to a very "narrow" late winter peak, while the 1-0 stock, which also experienced a late autumn low, maintained high levels of RGP from early January through mid March. Both age classes resumed low RGP levels with the onset of bud break. Possible explanations for these differences include: 1) a root pruned, 1-0 seedling has a much higher proportion of "new" suberized roots than a root pruned 2-0 seedling, and/or 2) RGP has been shown to be related to bud dormancy and an indeterminate 1-0 seedling apparently has a very different bud dormancy cycle than a determinate 2-0 seedling. Further research i s needed to evaluate the feasibility of planting 1-0 eastern white pine, a practice which might be justified by it's much longer "lifting window", much higher root/shoot ratio, and the substantially lower cost of producing 1-0 seedlings.
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Author(s): Kurt H. Johnsen, Peter P. Feret
Publication: National Nursery Proceedings - 1986
Event:
Southern Forest Nursery Association
1986 - Pensecola, Florida
