Translation:You don't need to take notes today.
Nothing in this sentence literally equates to "need". The closest natural translation is probably something like "today, it's okay to not take notes".
Personally, I wouldn't go so far as to say that equating "it's okay not to" with "there's no need to" is a "loose translation", but I can see what you mean. It takes a step away from a literal translation (which isn't necessarily a bad thing) for the sake of understandability in the target language (which is usually a good thing).