Planting stock quality, root growth capacity, and field performance of three boreal conifers.

Abstract

The influence of provenance and length of storage on root growth capacity (RGC) was determined in 2 + 0 jack pine (Pinus banksiana (Lamb.), 3 + 0 black spruce (Picea mariana (Mill.) B.S.P.), and 3 + 0 white spruce (P. glauca (Moench) Voss.). All plants were random samples of spring-lifted production-run planting stock raised by the Ontario Ministry of Natural Resources and used in Canadian Forestry Service stand establishment trials in 1972 and 1973. Except for some fresh- and field-stored stock used in the first two RGC tests in 1972, all stock was cold stored, then withdrawn as required after specified storage periods of up to 5 months. The number of roots that elongated in solution culture during the 21-day tests were counted on a total of 3594 trees. RGC differed greatly between the two test environments, but common to both were: a rapid decline with increasing length of storage; marked differences between species in the order jack pine> black spruce> white spruce; and substantial differences between provenances, the more northerly provenances showing higher RGC. The field significance of these results is examined in terms of survival and growth up to the fourth growing season after outplanting. Several correlations were significant, but relationships were generally obscured by great within-treatment variability.