thinking about giving these old plug trays a go this year

thinking about giving these old plug trays a go this year. I gave up on them in 2015-16 after winter kill took out 90% of the confiers, I had thousands healthy in the fall, covered with snow and just stone dead in the spring. I’m fine it’s ok, some of those pine trees are 6 ft tall around my yard now. but this year I have some cold storage for the winter, and suspect I could surely keep plugs alive. still trying to understand how to use them, these can ship all summer right? probably only suitable for bushes or small perennials or trees with a slower growing root system? imagining an oak or willow would get root bound fast.. or am I wrong?