As my poster tech tree is worn out and is unsuitable for scribbling on, I have compiled a black-and-white version . If anybody else would like a copy, please e-mail me at Bubbubrff1@tesco.net (leave out the bubbub anti-troller) and I will send it to you - it's a 100KB zipped .bmp file, which prints through Windows on A4 paper.
EDIT: scanned on a different scanner, what was an 897KB jpeg file is now a 1MB bitmap which zips down to 100KB, and (thanks to Cabert, post #4) it's attached.
However, I hope to receive some feedback, especially in respect of any errors, so that I can if necessary produce a second edition. I would point out that, being black-and-white, there are no pretty icons, and I have not shown costs because these vary with speed and level. Nor is there space for the effects of each tech.
I have found it useful in that I can highlight whatever beeline route suits each game, and I can mark off techs as I get them, or even when I know that somebody else has got there first ! One game, one print, and lots of coloured pencils.

don't you have a color printer ;)

if you want feedback, just upload the file, and you'll get it

1. Yes, I have a colour printer. But I wanted b/w so that my scribblings in colour would be more easily visible.
2. Upload file where to ? And how ?

edit your first post, go advanced, there is an attachment button (your file needs to be less than 500kb)

Other than that you can put a link to your web site, or to any hosting site.

Upload it here: http://www.imageshack.us/ and copy/paste the forum link.