Do you already have an idea of its structure? I mean that, you could make sub-branches (if possible of course). A main branch? For example: infantry, and in sub-branch, all its technologies? Who belong to him? Light infantry, elite, etc ... But with color codes?
When do you think ?
Of course it is easy for me to say, than to do.
Still, create, a tree with so many technologies, I take my hat off to you.