If below 68F, consider an underquilt and/or topquilt. The underquilt is more important, especially if it's windy. You can use a sleeping bag or light fleece blanket as a topquilt, especially if it's not particularly cold. You might also want to consider an inflatable pillow (or just bunch of a spare article of clothing).
Also consider carrying a small emergency bivvy in case you can't find any suitable trees.