I think the American broadcast was edited...
For example, there was this exchange very near then end that seems cut short:
Clara: "How will they explain this tomorrow?"
Doctor: "You'll all forget it ever happened."
Clara: "We're not going to forget an overnight forest!"
Doctor: "You forgot the last time. You remembered the fear and you put it into fairy stories. The Human superpower -- Forgetting. If you remembered how things felt you'd have stopped having wars and stopped having babies."
At this point in the "BBC America" broadcast it cuts away to a shot of the Earth, right before Clara presumably says "That is the dumbest thing I have ever heard. You do know that humans have cameras, like fucking everywhere, yeah? Like in this very episode you literally saw children taking pictures with the cameras in their phones. Are you saying tomorrow we'll all wake up and say 'Why do I have so many damn pictures of trees on my phone? I sure made a lot of crazy Twitter posts with #overnight-forest-WTF?!' and we'll all just push delete and go about our business? Or ignore the fact that some kid didn't mass-call every phone on the planet? 'Say, did you get a weird phone call from some British kid about not hurting trees? Meh, must have been a wrong number!' Or will people just think it was some crazy Arbor day stunt? And furthermore, wouldn't extra oxygen just make *everything* burn worse? Shouldn't it have been the reverse, pumping as much CO2 into the sky as we can? And where are these glowy life-force tree-growing things when it comes to climate change, huh? Why don't they make the trees fix that shit for us? And why save humans at all? We're *terrible* for the environment, just the worst! You'd think that they'd try and kill us instead. Actually if that were the case your stupid speech about fearing the forest would actually make sense because teaching your children to fear something that is actively trying to kill them is entirely appropriate."
Can anyone confirm?