[MatthiasWandel]

I'm pretty sure that wood was birch.

As for gaps in joints, if its a small gap, it doesn't hurt. I actually did some tests in that regard, linked from the article. http://woodgears.ca/joint_strength/glue_methods.html

A small gap actually helped. Probably because the glue soaks into the wood, so a joint without any gap sort of runs out of glue too quick (my theory). But it suggests that putting glue on and leaving the joint open for a minute may be beneficial.