Disclaimer: I'm a rookie at DF since I just started playing the other week.
This happened to me too: status war with the nearby elves when looking at the world map. They get offended if you cut trees or offer wooden items for trade (including items with wood as part of the production: soap, clear glass etc). More details in the wiki.
I did get a message from them saying that if I don't stop to cut down trees, I'll have to face the consequences. Then some time later a diplomat arrived and negotiated, agreeing on a 'quota' of how many trees I could cut down per year without consequences.
They haven't actually attacked me, but I've stayed clear of cutting down more trees than agreed. So if you go slow with the logging and save before making a trade with eleven merchants (it is hard not to offend them by offering the wrong goods), you should de-escalate the conflict.