ROOT PRUNING OF NURSERY STOCK

Abstract

In the fall of 1958, an experiment was begun at Midhurst Nursery to study the effects of root pruning at different stages of growth and at two depths, on 3-0 stock of white spruce (Picea glauca (Moench) Voss) and white pine (Pinus strobus L.). Root pruning was done by undercutting broadcast-sown seedbeds at two inch and four inch depths; in the fall as 2-0 (Sept. 16, 1958), in the spring at start of growth (April 30, 1959), during flush of growth (May 28, 1959) and towards end of terminal growth (June 25,1959).Seedbed counts were taken before lifting, in fall 1959, to study mortality. Random samples were taken on date of lifting (Sept. 17, 1959), for laboratory measurements to study effects on seedlings size. Other random samples were planted in experimental designs at Larose Forest. Counts of survival, and measurements of terminal growth were taken at the first, third and fifth year after planting.Results showed no mortality in the nursery but that all root pruning reduced height growth. Root pruning of white spruce after the flush of growth (June 25) increased survival and growth after outplanting, over that of unpruned stock. None of the treatments increased survival or growth of white pine. Depth of root pruning had no significant effect.