hillside erosion

So.. I live on the Oregon coast... I have a half acre aria behind my house that gets sun all day. When we bought the house the space was 100% covered with blackberries.. some spots were 8 to 10 feet tall brambles. I have been removing them over the past year on the weekends. The plan is to ultimately have food gardens and maybe a greenhouse. What ive been doing is cutting the brambles down to the ground and chopping them into mulch.. I have been mowing flat arias, but there is a lot of steep hillside on the plot. everyone in the aria keeps telling me to use herbicides. I do not want to put that stuff on my land. I plan, instead, to string up a solar electric fence and put a critter back there to eat the blackberries.
I am trying to decide between a pig and a goat. We would eventually slaughter the animal for the freezer. I like to eat goat, but I love pig.. I have never raised either, but I have read that pigs will root out the berry crowns and eat them, killing the plant, where as a goat would just eat the new green growth, taking longer. This makes me lean tward pig. But! Given the steep hills that I am dealing with on about half the space... would the pig cause a lot more erosion than a goat?
Anyone have experience with pigs or goats in steep arias?

I'm no expert on grazing but during my geology studies i was taught that a lot of the prehistoric climate shift, soil degradation and subsequent erosion around the mediterrean was partially caused by logging and subsequent overgrazing by goats and sheep which prevented spontaneous regeneration of forests.

Whatever critter you use - the taste might be wonderfull


One way to cope with erosion is by terracing your hill.

In prehistoric times till the early 20th century, farmers in Europe did this (among other methods) by a combination of hedgerows and plowing. Essentially, you establish a hedgerow more or less around a contour line on your property. Then you plough the lower part so that the furrow falls downhill and the upper part falls the other way.
The hedgerow breaks the speed of the runoff and slows down and catches any eroded material from uphill. So the lower part of the uphill part rises while the top of the plot loses height due to erosion and plowing. Each plot on your hill side experiences a reduced soil loss. Ultimately you get a short, steep hillside under the hedge followed by a flattened area untill you reach the next hedge.

We call this landscape form a 'graft'. There is a wiki that describes more or less how it looks but the way it forms could be improved upon. It's Dutch so use autotranslate. https://nl.wikipedia.org/wiki/Graft_(hellingknik).

The idea to 'build' fields of this nature has some comparisons with the english ridge and furrow system https://en.wikipedia.org/wiki/Ridge_and_furrow The closest english wiki to a graft is the lynchet landscape https://en.wikipedia.org/wiki/Lynchet You could consider a graft as an improved version of the lynchet where the hedgerow catches runoff and the transported sediment. The hedgerow also provides an improved microclimate.


Another way was by actually building terraces. This was really labour intensive and was only done to support cash crops (wine) or near settlements where space was at a premium. Check pictures of old medieval terracing.

I farm on steep land. I fence across the slopes with the contours as much as possible. In time this creates terracing through the action of water, wind and hoof. I also create terraces through machine work. This is how farming has been done on steep land for millennia and it works.