"R. V. P.," Cincinnati, O.: The juices of a tree are drying out through the bark, and especially through the most recent bark, all through the winter. The more severe the winter the greater the draft. All this loss has to be made good by the roots. Though encased in frost their work of absorbing moisture must go on and does go on. It must be worse for them to have to thaw out their drink than to have it without thawing. Hence you will find it a great help to a tree to mulch or otherwise prevent the frost from entering deeply.