How Many Men Would Survive?

You call your team and 150 men line up in the courtyard and everyone has been through special training but what you don't know is what you're up against
"Dan are you ready to defend?
"Yes sir, all my men are here and ready"
"Ok I want you to head out to the plains to attack the enemies head on"
"Ok sir"
As your men and you walk towards the plains another one of the kings generals says,"It would be a better tactic to go into the forest and charge them from the sides"
You say...