"It's a great opportunity for me to gain some experience of first team football," Henty told the Official Reading website.
"I first heard about Forest's interest about a month ago, but I had a niggling injury on my ankle so it couldn't happen then. But I found out on Wednesday that I'd be leaving after the reserve game with Fulham so it was a sudden move really.
"Forest are a massive club and they're only four points behind Bristol City for an automatic promotion space, so they are going to be really competitive games in front of big crowds - I'm really looking forward to that.
"Hopefully I can go and have an influence on their season by playing well for them.
"It's going to be totally different for me being involved in games which mean a huge deal to the fans and club.
"Academy and reserve games are important for development, but there's nothing like the first team. There are huge things at stake for Forest and I'll be giving everything to their cause."