I reread your post. Sorry I missed it the first go around. I believe your young root system is too small and tender to uproot like a larger tree. Is it possible to bring them indoors and use a glowlight? For best results, it is suggested that young seedlings not go dormant. Here us a standard pole light fixture I use with grow lights indoors (Target $19.99) Bulbs from Walmart.
Here is the root structure if a mature tree. I'm afraid your young trees will look nothing like this. Instead, will be a fragile small collection of white immature roots. It will be a risk to uproot them. And suggest not.
