there be a couple threads, on the ATV unit. were it mounts on front, and you just drive up and it clips the saplings, and you then carry the sapling were ever and drop it off. i want to say the big scissors per say on the front had one hydraulic cylinder or like on it. to help cut saplings off near the ground.
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been running an electric corded pole saw, Remington 8.5 amp, 2 in 1. (chain saw or pole saw) i wish the chain was multi angle. been running on a generator a couple times as well. guessing around 100 to 150 feet of extension cord. no way i could get a tractor in some spots. and the branches on bigger trees would not work to well without a good angle on the branches. the pole saw does not require me to bend over cutting up stuff on the ground, or reaching in through some smaller bushes. i can stand outside of the limbs and cut right near the ground.
i would not recommend the remmington 2in1 i have, 4 screws to take cover off that goes over the chain. (to much crud gets caught up inside under the cover) and electrical wires are not protected from all the saw dust/chips that come through the chain. had to return unit 1st week, due to saw dust getting into windings and causing it to smoke up and burn motor up.
a straight pole saw (not a 2 in 1), that is multi angle, more likely easier to deal with. i would most likely still recommend electric corded. even though corded. the 2 cycle gas engine ones weighs more. and many times. holding the entire weight with one arm extended. i doubt a battery version would give me enough run time, to cut up a tree and then cut up all the branches into small enough chunks to man handle easily.
i been cutting tops off saplings, and then going back and running chain saw blade right into the dirt (granted it dulls the chain) but grow tired real quick when stumbling and/or nailing toes on stumps, or hitting a stump with a tire or mower blades. there just smaller saplings 6" or less. so quick and fast with chain saw.
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i state pole saw above due to....
most of all the sapling here on the farm are in nice large clumps. near other larger trees, or a creak, pond, fence line, etc... and no way to actually run a tractor right up to and over the saplings.
most of the videos i have seen all show nice open pasture, nothing else really around but weeds. on some of the equipment.
most of the larger 4" and up trees on this farm, have long enough branches on them that would take me out (scratch me up, nocking me head off, taking out fenders on tractor, puncturing hole in tractor tire, if fell just right. ) if i just went right up to them and tried to take them down with tractor.
if i had a grappel for the FEL (front end loader). so i could just go around cutting branches off larger trees, and cutting bushes and saplings down. were i did not have to cut up all the larger branches up, that would be a huge time saver and easier. dealing with all the mess. and still allow me to pick and choose how and were to cut.