Let's try something. Advance into a good range for the archers. Have them fire in half volleys; one half fires at a high angle, to get them to raise the shields. The other half, a few seconds later, so as to hopefully cause the two volleys to arrive nearly simultaneously, fire in a more straight line/moderate angle, to shoot them whilst un(or at least less) protected. Our archers will be in front of our formation, knights and footmen behind, heavy infantry on the flanks. This will continue until they get fed up and charge or we run out of arrows. In the first case, the archers will retreat and head for the flanks, aiming to get around to their other side and fire upon the mass of enemy warriors that will presumably be created. Meanwhile, our knights will take a defensive position and counter-charge within the last two dozen meters of the enemy's charge, whilst our light infantry support them as they can, and heavy infantry march to flank and crush them. Leave an opening for them to flee from, even between the archers, who should be accompanied by any lancers we have to run down enemy stragglers and provide protection.
In the second case, the archers will fall back, their job is done. Meanwhile, our lancers will maneuver through the forest, while our heavy infantry will make up the front line, supported by knights dispersed among their ranks. Light infantry will make up a reserve force to help plug possible breaches. At a signal from us, lancers will come in from the enemy's flanks to help crush them, while light infantry will suddenly surge forward, as we'd have been fighting conservatively up til that point.