Seasonal variation in root hardiness of container-grown Scots pine, Norway spruce and lodgepole pine seedlings
Lindstrom, A.; Nystrom, C.
Canadian Journal of Forest Research 17(8): 787-793
ISSN/ISBN: 0045-5067 DOI: 10.1139/x87-126
In studies at Garpenberg, Sweden, seeds of 3 provenances of Scots pine and Norway spruce and 1 provenance of lodgepole pine were sown in 50-ml multipot containers in May and July. The seedlings were initally grown in the greenhouse, placed on pallets outdoors in July or Aug. (first or second sowings, respectively) and placed in a polyethylene tent with open sides in Oct. Seedling roots were frozen to -20 degrees or -25 degrees C in 6 tests during Sep.-Apr.