Wildfires have caused emergency services to declare incidents in north Wales, Derbyshire, Hampshire, Durham, West Sussex, East Sussex, Devon and Somerset over the past week.
The R&A has not prohibited smoking at Birkdale, which is hosting the 154th Open Championship over the next four days.
But everybody attending the event – including players, staff and spectators – has been told to dispose of finished cigarettes safely.
Many professional golfers have been known to smoke on the course, including 1995 Open champion John Daly, Spain’s Miguel Angel Jimenez, who was famed for his love of cigars, and England’s Charley Hull.
Brown says he turns to smoking when his “stress levels go up” on the course, but joked he had to apologise to his mum for the habit.
He also revealed when he was young he asked his dad to stop smoking – then started doing it himself.
While Brown seemed quite sheepish about the habit in his post-round news conference, his ability to keep calm allowed him to post the joint leading score among the morning starters.
Brown recovered from dropping a shot on the fourth with birdies on the eighth and ninth, before converting five more on the back nine to shoot 66, level with South Korea’s Im Sung-jae.
However, American Jackson Suber battled windier conditions to move into the clubhouse lead on five under.
