Dormant one‐year‐old seedlings ofAcer platanoidesL. were subjected to a range of cold storage temperatures for 6, 9 and 12 weeks followed by forcing at 20°C. For all storage temperatures there was a marked effect of exposure time on post‐chilling heat requirement for bud burst. The effect of temperature, however was less pronounced than the general assumption, in particular the chilling efficiency of 0°C was higher than reported by others. It is suggested that the optimum chilling temperature, i.e. the temperature that most efficiently reduces the need for heat units for bud burst, rises during the chilling process. This supports the hypothesis of a dynamic temperature response during dormancy release. A uniform bud burst could be obtained by exposing the plants to 0–8°C for 9–12 weeks. Terminal buds of insufficiently chilled trees frequently had bud burst later than the laterals, suggesting a higher demand for chill units and/or heat units for bud burst.