cutting 3" to 4" branches... and needing to deal with the branches after being cut is the issue. rotatory cutters (brush hogs = brand name) can only handle such a big limb before getting stuck and stopped by larger branches.
the old 1954, allis chalmers ca tractor with bellow mower, with muffler i am guessing around 6 to 7 feet off ground, then your head about another foot above that... call it 8 feet. a couple times a year, i go around with another person normally my mom. 1 driving the pickup truck, while the other person is in the bed of truck, using pruners and like to cut down branches. in the better areas, we just toss the trailer on as well. and cut and toss into trailer as we go. though some areas it just ends up being a pill of limbs on each side of truck, and come back for them later with empty trailer. vs getting in/out of the truck non stop dealing with branches that fall out of hand.
the truck takes a few scrapes, we take a few scrapes from the branches, but *shrugs*, just how it is.
if we need to, we will brake out a 8 or 12 foot fold up / A frame ladder. but that generally is pushing it, and the tree limb is really eerking us. other wise, mowing = another larger turn around the branch.
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i am not much for running a chain saw in back of truck bed (safety), and if i did, it would be the smallest possible chain saw possible. "way to much over head work" less weight the better.
i do NOT recommend putting someone in bucket of FEL (front end loader), way to easy for the bucket to dump, and bye bye person within it. more so working with tree branches that could catch the levers / joystick. *been there done that* not with person in FEL bucket, but catching a lever/joystick.
--i am uneasy with it, but they do sell some "man lifts" style setups, that attaches to FEL's. but still just does not seem safe to me.
if you had a mini excavator or a backhoe, i think i remember seeing a couple hydraulic driven chain saw blades, that one could swap out the bucket for.
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but out of all options, the tree companies most likely have best setup... the man lift / bucket trucks. what many electrical / telephone pole companies use to raise there workers up to the tops of telephone poles, or get in and cut down the trees. (from the tops down) vs just cutting tree at the ground and letting it fall over.
you might see if you could rent a bucket truck some place (not sure if that is possible?) you can rent self propelled scissor lifts / extendable man lifts / buckets with full size R1 ag tires, or R4 industrial tires on it.
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i no longer remember the "thread name" maybe a year old? it was hydraulic chain saws. same basic thing as the circular saw blade in the 1st post, but with a chain saw blade.
i think someone setup a hydraulic chain saw and a wood splitter (turned the FEL bucket into a wood processor) but this was for logs already cut, not for branches.
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with everything said, the hydraulic motor, the extra valve, hydraulic hoses, and the fittings. are going to run you a few hundred bucks.
i am going to say go with others with a pole saw, or circular saw on the weed whacker or like. vs trying for a tractor mounted option.
some of the "straight shaft" weed whackers / trimmers, you can buy a pole saw extension for it. pull off lower half trimmer, and snap on the pole saw extension. if you have any ponds / lakes you need to deal with (cutting banks). folks have used the "hedge trimmer" extensions. as a heavy brush / tall weed whacker. other words turning the hedge trimmers into more like a sickle mower in idea. 1 engine and a few different extensions *shrugs*