Since it's wood you could use a small finishing nail or screw.
If you used silicone you'd want to let it air out for awhile before putting your dragon back in. Silicons put off some nasty VOC's, you don't want to be breathing them and you definitely don't want your dragon to.
I work with silicone all the time in my line of work, and the one time I ever did in a not very well ventilated area nearly sent me home. It's some harsh stuff in an enclosed area.
Thats what I use for my reptile hammock. works great. And since the hammock is just hanging on the hooks it's easy to take out to make cleaning his tank easier, as well as cleaning the hammock.