Our morning task on clear days has been clearing a forsythia overgrowth along the north lot line; the branches tip-root as our neighbor’s bushes creep southward toward the sunlight. The process involves ramming a six-foot octagonal high-carbon / tempered / tougher than nails / rings like a bell steel bar (measuring a generous 1-1/8 across the flats) deep into the dirt under the plant, kicking a 4×4 inch block against the bar, pushing downward with all my weight to pry the plant upward until something deep underground rips, then repeating from all directions until enough big roots break and the mass tears out:
Then it’s on to the next plant.
The turmoil exposed a run of black PVC pipe along the lot line, although one end seemed firmly anchored. More excavation revealed a giant grape vine root growing around the pipe:
I had to sever the pipe with an axe on both sides to free the root:
The pipe originally carried water from the Mighty Wappinger Creek along the east lot line, 500 feet away and 70-ish feet down, presumably to water the previous owner’s plants. As far as I’m concerned, the remains of that pump will remain on the bottomlands forevermore, but at least we’ve cleared the remains of the plumbing.
Mornings like that make writing CNC code look downright attractive, but I’m developing the cutest little biceps …
The Smell of Molten Projects in the Morning 
You have my sympathy, Ed. Used to do rhododendron clearing (for “fun”) on Scottish hillsides. Steel bars and mattocks would work on the small bushes. The real biggies needed a tirfor — basically a come-along with a 3+ ton rating. No matter what you use, it’s murder on your hands.
The only old pumps I find interesting are hydraulic rams: start ’em with a hammer and they’ll run forever, although they have to leak a fraction of their water to work. A friend lived in her remote cottage for 10+ years and didn’t know how her cistern (uphill) was always magically full. She was clearing brush like you and found a wooden box emitting thumping noises and a stream of water underneath.
You have no idea how pleased I was to not deploy the comealong!
I’ve also been clearing brush for weeks, all invasives. My forsythia is under control. Primarily it has been bush honeysuckle and privet, but there has been a fair amount of multi-floral rose. The honeysuckle breaks off or pulls out without too much effort unless it has gotten to be quite large (+3″) then it requires the tractor and a chain. The Chinese privet is a lot harder to pull out and usually require being cut off. The most vicious is the multi-floral rose with horrific thorns. I usually have to dig a few thorn tips out of my hands in the next day or too once they made themselves noticeable by becoming red and sore. I take advantage of this time of the year to do as much as possible so that I can avoid the poison ivy once it leafs out. I have gained significant area back all along the property borders by doing all of this and now spending more time in the woods. It’s good exercise but but the satisfaction of reducing the sources of seed that only produces more is worth it. After all the big plants are gone, the smaller ones are easier to remove.
We killed off nearly all of the thistles and roses over the last few years, so this effort didn’t involve bloodshed and, with a bit of luck, we won’t do it again for a long time!
I’ve seen steel bars like that before – was that a torsion spring out of a large truck (beer truck or larger)? Those things are amazing.
At least on the Left Coast, they’re sold as “digging bars”. 6′ long, with a point on one end, and widened to a sort of chisel on the other. I use mine to get through the shale hardpan that’s just below our dirt. Cheaper than a jackhammer, and (usually) less annoying to use.
A shorter variant has the chisel blade and an 3″ diameter head so you can use a sledge hammer. I have one, but the longer version usually does a better job.
Most of my brush clearing uses either a mattock or a Pulaski https://en.wikipedia.org/wiki/Pulaski_(tool) If I have to get a dedicated axe or the digging bar out, I know I’m in trouble.
I have a sacrificial axe: the poor thing expected a glorious life cutting tree trunks, but has gotten used to thwacking roots. Definite disappointment in the tool rack …
Nope, it appears to be made for the task: a chisel tip and a flat end. I ground off a mighty mushroom, with plenty of showy spitzen-sparken action, to restore the flat; I’ve never whacked it with a sledge, though.
Ramming the thing into the soil from a foot or two away builds up sufficient momentum for my simple needs: repeat as needed to poke it far enough under the root ball for serious leverage.