Learn Turkish: Bu ıssız ormanda dallar bile korkunç mu? - Are even the branches scary in this desolate forest?

In English, "even" comes before the word it emphasizes ("even the branches"). In Turkish, the emphatic particle bile always comes immediately after the word or phrase it modifies. So, to say "even the branches", you must say dallar bile.

Could I put the question particle mu right after bile, like "dallar bile mi"?

You could, but it changes the focus of the question. Putting the question particle after the subject (dallar bile mi korkunç?) emphasizes the branches: "Wait, are EVEN THE BRANCHES scary?" In our sentence, mu is at the very end (korkunç mu?), which places the focus on the adjective instead: "Are even the branches SCARY?"

What exactly does ıssız mean in ıssız ormanda?

Issız means deserted, desolate, or uninhabited. You will often see it used to describe lonely places with no people around, like a deserted island (ıssız ada) or, in this case, a desolate forest (ıssız orman).

Why is there no buffer letter 'n' before the suffix in ormanda, like there is in words like bunda?