The Englishman was in the second group to go out at The Celtic Manor Resort on Thursday morning and made a positive start as he carded seven birdies and one dropped shot in his opening round.
The World Number 664 has been in good form since the resumption of competitive action following a four month hiatus due to the global health crisis, carding a top 30 finish at the Betfred British Masters hosted by Lee Westwood and a tie for 44th at last week's English Championship.
Tree continued his momentum from Hertfordshire with a birdie at the first, only to record his only bogey of the day at the next to return to level par.
But he trended upwards thereafter with a gain at the fifth before picking up successive shots at the eighth and ninth.
Another birdie at the 11th moved him clear at the top at four under and when he carded a three at the par four 15th, his lead extended to two shots.
Australian Min Woo Lee, Swede Sebastian Soderberg and Belgium's Nicolas Colsaerts closed in to within one shot of the leader but Tree restored his two stroke advantage with his seventh birdie of the day at the par three 17th for a six under par 65.
Colsaerts carded four birdies in his opening 13 holes, while Lee enjoyed five birdies - including four in a row before the turn - and a bogey through 12 to sit two adrift of Tree at four under.
Soderberg carded five birdies and a bogey after ten holes while Betfred British Masters hosted by Lee Westwood champion Renato Paratore joined them at that mark through 12 courtesy of four gains and no dropped shots.
Italian Edoardo Molinari, who was part of Team Europe's Ryder Cup winning team at this venue ten years ago, was in a group of four players at three under during their first round, in the company of Dave Coupland, Belgian Thomas Pieters and American Sean Crocker.
English Championship winner Andy Sullivan, who was playing alongside Paratore, was one over after 12 holes at The Celtic Manor Resort, which saw only 23 players in the red numbers during the first morning.