Re: I noticed that a lot of the photos of tobacco plants on FTT are very pyramidal.
The characteristic that determines pyramidal vs. columnar is the variation in leaf length from bottom to top of the stalk. If there is little variation, then the plant appears columnar (regardless of the stalk height). If the upper leaves, even when mature, are progressively shorter than the lower leaves, then you see a pyramidal shape.
Many Indonesian types and Oriental types are columnar. Florida Sumatra, which is derived from Indonesian Deli leaf, is columnar. Most seedleaf and broadleaf varieties are markedly pyramidal, as are Orinoco flue-cured types. My burley varieties (including Harrow Velvet) have tended to be pyramidal.
The traditional Cuban Criollo, Corojo and Vuelta Abajo are pyramidal "Spanish" types, but surprisingly, Corojo 99 is columnar. Just today, I was noticing the truly huge size of the remaining upper leaves of my Corojo 99.
Other than its implications for larger maduro leaves, overall productivity, and increased risk of blowdown, I'm not sure that there is much significance to this determination.
Bob