I created a new save game with a large number of planets, and selected "Any planet start" to start on Muluna. This resulted in the starting planet being Lignumis while starting tech tree being Muluna.

If you look at the tech list on the left, you can see that wood science pack is available so I think it is possible to play. There is no explicit compatibility for this combination. The requirement for wood when landing on Muluna could be problematic. Check the settings for Lignumis to disable some of the wood requirements. If you have the Lignumis Director's Cut mod enabled, you should disable it.

You don't get it; I started on Lignumis world instead of Muluna despite it being the selected starting planet.

I totally understand. It is as intended. With APS you move Lignumis away from Nauvis to another planet but you still start there. Lignumis is meant to be played as the starting planet because it's main thing is the burner stage. If you don't want that you need to add Lignumis at a later point in your game.

I have the same problem as Hasen. When I select "Any Planet Start" and choose Mulana, I end up on Lignumis—just like they did—with the Mulana technology tree. This works fine for a while; however, when I try to leave the planet for Mulana using the Rocket Silo, I have to unlock the destination first. But I can only do that if I produce liquid fuel—something I cannot produce on Lignumis due to the lack of a Chemical Plant, which only becomes available on Mulana. So, I'm stuck in an endless loop: I need to produce something in order to leave the planet, yet I cannot produce that very thing while I am on it.

The mod wood-industry highlights Mulana on the Space Map but travel is nothing working.

You probably moved on but I had a look at it to understand the problem. The mod combination just wasn't compatible. In the version I just released I added explicit support for Lignumis + Any planet start (Muluna).

Error loading mods: ...is__/prototypes/compatibility/any-planet-start-final.lua:165: attempt to index a nil value
stack traceback:
...is__/prototypes/compatibility/any-planet-start-final.lua:165: in main chunk
[C]: in function 'require'
lignumis/prototypes/compatibility/final.lua:2: in main chunk
[C]: in function 'require'
lignumis/data-final-fixes.lua:2: in main chunk

Do you have other big mods active? Maybe K2SO? Do you also get the error with just Lignumis, Muluna and APS?

The problem seems the technology "electronics" is missing, which is a vanilla technology. If you don't know which mod does that, disable Lignumis, create a savegame and I'll have a look.

Identifying a specific mod is always a real problem for me. I have over 480 mods running and almost all planets from the mod portal. I don't have anything like K2SO or other big packs. I only play the Bobs mods. I only know that Lignumis 1.6 ran without problems but I just couldn't get off the planet and I didn't update or add any other mod in that time. 1.7 unfortunately makes this start error even before I can load my save. I now have 1.6 again and simply cheated with the Creative Mod to get off the planet.

Yeah with many mods it's not easy indeed. Once you are done with Muluna you could remove APS and update normally.

Removing APS would be an option for updating Lignumis, but I have a number of planets running (Froodara, Hexalith, Gerkizia, etc.) that require APS as a mandatory mod. Therefore, I have to remain on version 1.6.0 until this issue is resolved. Nevertheless, thank you very much for trying.