Sleeping in could be a good thing

Regeneration of seedlings around fragmented forests or along treelines can be slow. Once shelter is removed, there can be dramatic changes in microclimate over small scales. For snowgums (Eucalyptus pauciflora Sieb. ex Spreng) regenerating in sub alpine areas, there is an asymmetric pattern of regeneration (Ball et al 1991). This pattern correlated with an avoidance of early morning light and cold temperature. Further research has shown that the time of day when seedlings receive light influences the patterns of growth. This timing was manipulated by the use of (50% shadecloth) shade screens oriented in the four cardinal points around seedlings in the field. The amount of light received by seedlings varied but the minimum temperature remained the same. This was due to the same night sky view. Seedlings on East and West sides received the same total radiation, but at different times of the day. Results from growth experiments in the field show double the growth on the West compared to the East. Plants on the North side (which receive light all day) showed growth intermediate between East and West. This indicates that a reduction of light enhances growth that the interaction between temperature and light varies during the day, and that intercepted light does not translate directly into growth. Around fragmented forests and along treelines microclimate varies on small scales. Some of these microclimates may be beneficial to growth, others may not.