I once rode from Carna to Galway on horseback. It's bleak, and there are many tiny abandoned farms, but that's left over from the days when Cromwell exiled the Catholics. Most of that area never got to industrial scale agriculture. East of Galway, towards Dublin, there's more partitioned farmland, much of which isn't growing useful crops. In County Cork, where the author is, the coastal area to the west is similarly bleak, but the interior regions have farmland. And sheep.
Sheep seem to be the big problem. They will grind vegetation down to nothing. If trees are cut down and sheep brought in, the land stabilizes as overgrazed pasture. Then it won't support many sheep, but what it will support will keep it overgrazed. The author seems to want to return more of the farmland to its natural bleak state. Maybe with more trees. The author is unhappy that there are "no big and wild areas that have bears and wolves and mountain lions." Bears have been extinct in the wild in Ireland since 1000BC or so. Hard to blame industrial agriculture for that. The last grey wolf was killed in Ireland in 1786. Somebody sighted a mountain lion in Cork County in 2018, and there was a major freak-out.[1] The population is used to a predator-free environment.
[1] https://www.irishpost.com/entertainment/ireland-unexplained-...