Some of these machines are not bull dozers. Most of them are tractors with forestry plows and other equipment but the other machines are bull dozers.Why are they clearing all the shubery with chains? The ground looks so dry, are they anticipating on planting something there or???That wheeled tool looks really handy for clearing out the stumps of plantations after they have been cut and ready them for replanting. Although I wonder if it is worth the effort when those stumps will just become organic matter if left alone within what 20 years or so?