I haven't finished the Construction, Production or Economics trees yet.
I suggest that you not continue going through each of the existing trees and modifying it... What we really need to do is re-examine the entire tech tree, including the categories that exist now, and do some reorganization. Particularly for Economics and Construction, I expect the categories to be rearranged somewhat and certainly renamed...
Probably Economics should be just a part of a larger Socioeconomics category, or something similar, which would include a few real-world inspired economics systems (but certainly not just limited to "Planned" or "Market" as that's a false dichotomy and far to limited in scope for a future galactic empire type setting) and also various methods for manipulating or controlling ones own and other empires' populations, and dealing with multi-racial empires.
Construction should probably be renamed to something like Infrastructure with a branch or two for enabling techs like architecture, organic structures, monofilaments, force-field structures, and orbital or gravity-dependent methods, and a few items related to resource sharing on system or galactic scales.
Going through each tree individually also has the problem that it tends to encourage adding more to each tree, without considering the effect on the whole tree. The previously-posted growth and learning trees have 15 theories in them. This is probaby too many. Ships has 32, which is too many, although we don't need to be quite as restrictive in ships given that we'll have several independent branches in that category, more so than in other tech categories.
As for how to reduce the number of theories... In general, there shouldn't be so many cases where a theory is just a delay before a desired application can be researched. If that's all a theory is doing, it might be better to remove the theory, put some of its fluff description into the application, and make the application depend on the previous theory instead.
Also, Bigjoe5 in particular, could you spend a bit more time making sure the connections between theories make some sense? I know you're trying to make the trees have interesting shapes, but a lot of the connections in the current tree(s) don't seem to have any reason given the actual names and descriptions of the techs themselves. I mentioned a few in the learning tree previously, but I'm seeing numerous other odd connections while looking through the tree(s) now.