So Northern Vietnam managed to defeat the Vietcong and Americans by the old technique of trees and always kicked their asses as an ambush. It leaves me one thing: why did the Americans not do that same technique for a further Northern attack in the war?
Hi there! I'm not quite sure what you're basing on, but the idea of 'the trees talking Vietnamese' is drawn not from actual historical examples but rather from popular cultures and, yeah, memes. Please don't learn history from HistoryMemes.
This is not to say that neither side used the environment to their advantage. Using foliage as camouflage for ambushes was widely used by both sides. I have previously written about PAVN ambushes in this post, which hopefully will provide you with a better understanding of how they were executed.