The minifundio was the result of a system of inheritance that distributed land plots in a closed rural system to a growing population by requiring that equal shares be bequeathed to every descendant. The land had become subdivided so much that most of the plots were too small to support a family or to be economically viable. You can read more here .
Many Galicians went to Central and South America, abandoning their smallholdings in the process. The effect of this has been that in any village in Galicia you might find properties whose ownership is unknown. This is in addition to those whose ownership is known but for whatever reason have not been maintained and are falling into ruin in the case of houses, or are completely overgrown in the case of fields, called fincas here.
On one hand this is slightly disturbing but on the other, it is nice to see nature reclaiming some space. There is a finca very near us which is a jungle of ferns and grasses and I think there are some trees in there too. It's a shame for the trees as they start to disappear under the jungle and get strangled by rampant ivy, but it is a paradise for animals and insects.
I was kept awake a couple of months ago because of a dog barking. It turned out it was barking at a wild boar which was in that finca. I couldn't really blame the dog, but shout as I might at 4 am, that boar was going nowhere. It was snuffling around merrily without a care in the world. I couldn't see it but I could hear it. And the dog.