While operating on the Range 85 fire, Range 11 reported several brush fires near electronic targets. The 5th brush truck was manned by Station 2 and sent to Range 11 to handle those fires. At the same time Range Control called advising us they had another wind driven fire in Bivouac 15. Brush Trucks 36, 56 and 57 responded and found a very thick 2 acre block burning up range and in the middle of the land navigation course. Several soldiers were on foot operating in the area so crews had to give them time to evacuate the area. Crews made an aggressive direct attack on the fire and held it in the block of origin. The average flame height in the block was around 4 foot with occasional torching. Hardwood mixed in with pine made the fire difficult to get around and several wind shifts occurred during the fire.