You can definitely just send the trucks in. Whether anyone will be actually alive a few minutes later is a very different proposition. I'd advise against it. People underestimate just how hot fire can get and what it actually means to operate next to and within an environment that is essentially a furnace. A furnace that stretches all around you and up into the sky and is moving all the time. The air is hot and thick. Your protective gear is hot. Embers are flying around and if they touch something flammable they become a fresh new fire.
A few "trees across the road" means many minutes to clear that road. Which is surrounded by fire. Or soon will be. That wind could change any minute. Or the logs are still smouldering or on fire. So you clear the road and then a few hundred metres later you reach more fallen trees and massive ditch you can't pass. Now the fire has crossed the road behind you.
The firestorms suck up all the oxygen, and can cause massive 'fire tornadoes' that have literally flipped a fire truck onto its back.
It's not a question of 'just' sending the trucks in.