Root morphology and growth of bare-root seedlings of Oregon white oak

Root morphology and stem size were evaluated as predictors of height and basal-area growth (measured at groundline) of 1-1 Oregon white oak (Quercus garryana Dougl. ex Hook.) seedlings planted in raised beds with or without an additional irrigation treatment. Seedlings were classified into three root classes based on a visual assess- ment of the fibrosity of their root systems. Early-season and late-season height and basal-area growth differed significantly among root classes after accounting for initial seedling size. Irrigation significantly increased late-season height growth, but not the other growth increments. Recommendations are made for grading seedlings to increase the growth of those that are outplanted.