From Vijay Koul, Canberra, Australia
Adam Vaughan describes seeking willow seeds to deposit in an underground vault (25 May, p 13). In 1992, I studied Salix alba in the cold, arid conditions of Ladakh in India and observed that the seeds lose their viability six to seven weeks after collection. I noticed a reduction in germination after 14 days and no germination after 52 days. I suggest the Kew scientists check before banking seeds in deep freeze for long-term use.
