Kooistra 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.