In nature, the germination of dormant seeds may be triggered by different phenomena such as the cycle of one or more cold winters followed by the warmth of spring; cycles of burial followed by re-exposure to light; passage through a bird or animal gut, fire, or various combinations of these treatments. Artificial substitutes which can be used as dormancy breakage treatments often mimic these conditions and are termed pre-sowing treatments or more commonly 'pretreatments'.

It must be remembered that:

• There is no single method of pretreatment which is universally effective at overcoming the dormancy of all tree species.

• The level of dormancy varies between seedlots and individual seeds in a seedlot, hence there may be significant leeway in pretreatment durations.