INVASIVE SPECIES: Chicago could chop down 10,000 trees to fight non-native beetle Published: Monday, April 28, 2014 The city of Chicago may have to remove as many as 10,000 trees in a bid to stop the invasive emerald ash borer. Please subscribe to Greenwire to read the full story. Username: Password: Forgot your access codes? Recover them. Not a subscriber? Sign up for a trial. Ready to subscribe? Click here.