In the last 15 years I stored my budwood wrapped in a moist newspaper sheets, closed in a plastic bag and kept frozen in refrigerator at temperature of 23 Grad F (5 Grad C). I never had failure. I am using common freezer, completed with a self made control circuit sensing the temperature in the box and switching the main of the freezer on/off, depending on the set desired temperature. Temperature deviations in the interval 25 to 20 Grad F dont matter. Alexander Dragotin