Best time to air layer conifer

Can anyone tell me when the ideal time to air layer a conifer is? And are there any differences in timing between pine, coastal redwood, and dawn redwood?
Many thanks in advance

Hi Michael, spring is the best time. Normally May. Your could try now but they might not have enough roots to survive the winter. Pines can take up to two years to send out roots and the recommended method is tourniquet.