Woodland scenics is good, I mainly have 3/4 to 5 inch trees to represent dry shrubland. I'm planning on gluing lichens to the armitures and putting scatter on that.
If I was doing something less arid I'd have a serious look at 4ground trees
https://www.4ground.co.uk/4g-trees as they have a good range, and they seem pretty decent quality. They're a bit pricier but only a few will spice up your forest.
But any railway scenery trees should be good.
4ground also have a modular basing approach which allows you to change up your stands of trees.
What climate/environment were you thinking?
If the forest is dead consider putting dry leaf scatter on the bases, if it is scorched consider putting dry(if it is old) or green(newly scorched and fire hasn't reached them) leaves on some trees. Whatever you decide hope this helps.
https://www.youtube.com/watch?v=0pIS1DnkaHY&t=896s
Automatically Appended Next Post:
Alternately if you want to make the trees yourself. (I have no experience in this), but wire armitures and modeling clay, or so I hear. Worth looking on youtube.