I couldn't find any technology trees I liked, so I made my own. I thought I'd share it in case some of you prefer this tech tree to existing ones.
The tech tree is intended to be printed on two sides of an A3 paper (or a paper of similar size) -- one side with the tree itself, and the other side with the details of every technology (scale the images to your liking). Both sides are organized in tiers 1 to 7, where the tier number is the minimum number of technology purchases needed to acquire that technology (assuming you have no prerequisites).
It doesn't seem like uploading files to this forum is an option, so I uploaded the tech tree to BoardGameGeek . However, that website is a visual trainwreck, so I stay away when I can. In other words, if anyone leaves a comment there, I won't see it unless I log in, which might not happen again in aeons. Therefore it would be great if any of you could take a look at the tech tree and see if you find anything that should be fixed. My hope is that anything that needs fixing is spotted early, which saves us all the trouble of having to deal with a messy or incorrect tech tree.
Cheers!