Re: So which frames to start with?
Very likely. Poplar is the name of over 35 different varieties of trees in the willow, cottonwood and aspen families
Poplar lumber can be bought at Home Depot right next to Oak and Cedar. It is sold as a fine stain grade wood. It is not in fact Poplar but comes from a tree of the Liriodendron genes and is not in fact even related to the poplar. How it got called Poplar I have no idea.
Significant Minority vs Insignificant Majority, 20% of causes produce 80% of the effects.