Obfuscation, as in
The tree-obfuscation of the smoke
While obfuscate is somewhat less common than obscure, I have never heard the word obscuration before in my life; obfuscation seems more common to me. Ngram confirms that my lifetime has been marked by relatively high popularity of obfuscation, and relatively low popularity of obscuration. Worth noting that this trend is only about 40 years old, however, and obscuration at its height (in 1852) was far more popular than obfuscation is today.
Still, today, obfuscation is more than twice as common as obscuration.
All that said, the construction here is very odd, though. Consider this rewording:
The smoke's obfuscation of the tree
Identical in meaning, retains the emphasis on this obfuscation of the tree as a property of the smoke, and reads much better in my opinion.