and Bakker (2002) noted several lines of evidence suggesting that cool storage can have negative effects on seedling health. The rate of respiration is faster during cool storage than in frozen storage, so depleting carbohydrate reserves more rapidly. Certainly in the absence of light during cool storage, and to an indeterminate extent if seedlings are exposed to light (unusual), carbohydrate reserves are depleted (Wang and Zwiacek 1999). As well, Silem and Guy (1998), for instance, found that interior spruce seedlings had significantly lower total carbohydrate reserves if stored for 2 weeks at 2 °C than if thawed rapidly for 24 hours at 15 °C. Seedlings can rapidly lose cold hardiness in cool storage through increased respiration and consumption of intracellular sugars that function as cryoprotectants (Ogren 1997). Also, depletion of carbohydrate reserves impairs the ability of seedlings to make root growth. Finally, storage moulds are much more of a problem during cool than frozen storage. Kooistra and Bakker (2002), therefore, tested the hypothesis that such thawing is unnecessary. Seedlings of 3 species, including interior spruce were planted with frozen root plugs (frozen seedlings) and with thawed root plugs (thawed seedlings). Thawed root plugs warmed to soil temperature in about 20 minutes; frozen root plugs took about 2 hours, ice in the plug having to melt before the temperature could rise above zero. Size of root plug influenced thawing time. These outplantings were into warm soil by boreal standards, and seedlings with frozen plugs might fare differently if outplanted into soil at temperatures more typical of planting sites in spring and at high elevations. Variable fluorescence did not differ between thawed and frozen seedlings. Bud break was no faster among thawed interior spruce seedlings than among frozen. Field performance did not differ between thawed and frozen seedlings. Gallery See also Seed tray Transplant experiment References External links Transplanting to improve the landscape of your Garden Planting and Transplanting Trees and Shrubs in the Home Landscape Divider (in German) Horticulture