As much as the goats love blackberries, they can only eat so much. It's time for human intervention.
I read recently that a scythe can tackle blackberries. Please tell me more.
What kind of blade is best for blackberries? Is there a special technique?
Hans Quistorff wrote:I agree with the brush blade. Mine is American and slightly thicker. On the other hand I have found a hedge trimmer is most effective for cutting anything above waist height. Take it in sections from as high as you can reach downward. Let the goats and sheep eat the newly exposed leaves then come back with the brush scythe and cut the large stems. When you have worked back into the thicket some then use a broad fork to pry up the roots unless you intend for it to regrow for the feed. With a stand that high the root crowns will be the size of an american football.
Glad to see you mention the issue of getting the roots out of the ground. Scything or goats or anything else is only temporary if you don't get those out. And yes a patch like the OP described would have some massive root crowns.
I only have a grass blade, and it works fine. For the bigger vines I slide the blade in until I am touching the target vine with the sharp edge of the blade, then give a quick tug towards myself and it slices through.
Hedge trimmers are indeed helpful for cutting vines into smaller pieces.
I also recommend smashing the vines down with a heavy board, with you standing on the board. This is easiest when they are covered with snow or ice.
I have never dug the roots. You will have to keep mowing/scything/browsing the area for a few years anyway until the roots and seeds are exhausted. After a few years of mowing, the roots die.
There will be a few seeds sprouting every year for decades, just mow them down every year.