Of course 3d printers lay these strands in a 2d plane (and stack layers of these 2d planes), whereas trees grow in more-or-less one dimension. So wood has one strong direction and two weak ones, while 3d prints have two strong directions and one weak direction. And obviously 3d printed strands are layed out by boring and often naive algorithms that lack any of the beauty of naturally grown wood. Then again, for structural applications you also want the most bland and boring wood patterns possible.
With 3D printing, despite the analogy, I couldn't find any sources for strength along/across the "grain" so i'm not sure how accurate that analogy really is.
CNC kitchen on youtube does a lot of strength and impact testing, e.g. [1] (results at 9:55). "Across the grain" you have half the strength in PLA (and similar numbers in all filament types except TPU). Or if you prefer manufacturer numbers, [2] is the datasheet for a random PLA filament. It also shows worse numbers in every metric in the Z direction (across the grain).
The difference isn't as severe as in wood, but it's big enough that it is something you have to consider in structural parts
[1] https://youtu.be/dOzVuoBP9gY?t=535
[2] https://polymaker.com/wp-content/uploads/lana-downloads/Poly...
That said, if the part is small, and one can afford to print w/ 100% infill just put it in a tray of salt and bake to re-melt/re-flow to make a (more) solid part.
https://x3d.com.au/blogs/tips-and-tricks/pla-baking-the-secr...
