Hello there. I believe that the sentence is a bit grammatically incorrect. In my lowly opinion, the phrase para walang anuman makes that sentence kind of a bit derailed of what it really wanted to convey. Individually, the meaning of the words is as follows. Walang is the combined form of wala and the linker ng and this basically means "nothing or none”. Anuman, on the other hand, means "anything, whatever or whatsoever" depending on the context. Combining these two words walang and anuman could mean a different thing depending on the sentence usage. With that sentence you posted above, I can say the closest one is "for nothing or for no apparent reason." The trees are uprooted for no apparent reason. As: Ang mga punungkahoy ay nabubunot niya nang walang dahilan. I think that phrase will somehow fit because of the verb nabubunot (unknowingly uprooting). The verb gives me the impression that the doer is unaware of what he is doing. If however, that is not the complete sentence, disregard this meaning. On another note, I have this feeling that the sentence is incomplete. If your sentence is: Ang mga punungkahoy ay binubunot niya para walang anumang maging sagabal sa pagpapatayo ng gusali (The trees are being uprooted so that there will be no hindrance to the construction of the building.) this would make sense to native Tagalog speakers. In this case, walang anuman would somehow mean “nothing or there’s nothing”. Anuman in this case just added emphasis to the word sagabal. In the last sentence, anuman can be removed and yet the sentence still retains its meaning. You’re correct. Walang anuman means “you’re welcome” in Filipino. However, if it’s used in a sentence, you usually would see the phrase meaning “nothing” and then modifying a noun, where anuman will somehow act as an intensifier. See the last sentence. My explanation isn’t perfect and there are better explanations than mine, but being a native speaker this is how I will answer your question. :)

"Ang mga punungkahoy ay nabubunot niya NA paraNG walang anuman" (in this sentence, it says that the doer can easily uproot the trees) -He could uproot trees as if it was nothing at all.

Walang anuman is usually used as an equivalent of You are welcome but literally, it means, that is nothing like De nada or No hay de que in Spanish. It is also like De rien in French. In the sentence you mentioned,, it seems that it is from a classical book of myths in Pilipino. Though it is used only in classical texts, it is a little bit awkward. It means that He was uprooting the trees without much effort. But literally you may translate it as He was uprooting the trees like it was nothing at all.

"Ang mga punungkahoy ay nabubunot niya paraNG walang anuman" (classic) I view this tagalog sentence as correct. The "walang anuman" here is an adjective that describe the doer's (pron. "niya") capability as somewhat possessing a super power (?). To translate it in english and further exaggerations, it would go like these: 'he can uproot a tree in just a single hand.' 'he can uproot a tree in no sweat.' 'he can uproot a tree just like picking a flower.' in contemporary tagalog, the sentence would normally said this way: "Ang mga punungkahoy ay nabubunot niya na parang... WALA LANG." note: My explanation is merely based on the verb "nabubunot" which describe 'capability of uprooting' as opposed to "binubunot" which describe the 'act of uprooting'. :)

Walang Anuman literally translated would be 'it's nothing.' in that sentence it is used as Adjective which means nonchalant...