So, you got excited and bought more bare root trees than you know what to do with. Been there. The story continues... You grab your shovel and look for a place to plant them all. Suddenly, you come to your senses; then you panic looking at all those trees awaiting your decision. What usually happens next is the "panic planting" with the whisper: "I'll move them later."
Well, that needn't happen. You can buy plenty of time to make good decisions by "heeling-in" your trees. The strategy is simple: keep the root systems from desiccating until you are ready with your planting scheme. The technique is just as simple: Prepare a "heeling bed" filled with sawdust or wood chips (don't use Alleopathic material like cedar) and set your tree in there, just like you were planting them. The key is to keep the roots moist. They will be happy for a long time. I've actually got trees heeled in for more than a year. You can just pull them out when needed.