Best Trees For Living Fence Post (not Hedge) in a Steep Rocky Mediterranean Climate

I want to put in fencing on using a keyline design on a steep, rocky (just rock really) ground in a Mediterranean climate.  It is too steep for heavy equipment and a fence post pounder would just pulverize a wooden post anyway.  Each post would need to be drilled out by hand.  Digging would  be measure in hours per post hole, not post holes per hour - they need to be kept to a minimum.  (I will put up a related post on the best fences for a rocky ground)

My thought would be to do a high tensile fence (either single stranded or woven wire - each with a hot wire) with steel posts at the angle changes and corners with 'droppers' (no digging that just 'drop' in place to keep line from sagging and grow the fence posts 6" behind it every 16'.  Looking at the map even 55 steel posts seems daunting on this terrain.  To drill most of the holes I would propably need a concrete core drill if I can figure out how to make it drill deep enough.



Main Question:
What is the best tree to plant
- fast growing
- Straight trunk
- survive without watering after first few years
- can be pruned or pollarded to allow water for other trees and reduce the fire hazard
- Limited fire hazard - no eucalyptus
- Has a secondary use - e.g. fodder

Mediterranean Trees

I was leaning toward a carob for the fodder, but I'm not sure how fast (or straight) they grow
Lebanon Cedar could work, but I'm at 800-1200 ft elevation, and I think they want 2,000-3,000.  on the East and West Property lines I don't want to create a fire ladder so I think they are out.
A lot of people talk about black locust or thornless honey locust, but I don't see them grow here and I don't think they will survive our hot, dry summers.
Living fence or hedge would drink too much water and be too much maintenance.

Once the trees are established this looks like the best way to attach the fence: Board Method for living fences

My follow up question would be the best place to source these trees.

It's frustrating to see how few examples there are of this on the internet, does that mean it doesn't work?

I appreciate your input.

hau Patrick, If you fill out your profile on the control panel, we might better know where you are on the earth mother and that means we can taylor answers that fit your situation.
Since I have none of that type of information (look at my profile under my name to know what we need) I will give you some information about your ideas.
By the way, if you investigate a large area around your location and see no tree lines that  might be used for living fence, that can be an indicator that it doesn't work.
Especially if you are in Europe where such structures are still around from the middle ages.

Fast growing trees have the very real tendency to be short lived trees, or at least far shorter lived than the slower growing hardwood trees.

If you can get them two of the best are Honey locust and Black locust, both are very rot resistant, grow at a nice pace when young and then slow down as they get older and they both coppice well too.
The wood is one of the standards for wooden fence posts in the USA and other countries where they are growing (only the USA is the natural habitat for these two trees.
One other tree, the bald cypress is known for it's non rotting abilities and in swampy areas it is the prime choice for fence post wood.

Now, about the need to go deep, what is it that you are keeping in/out of the area you want to fence? That has a great deal to do with how deep a post needs to be sunk into the ground.
Surviving without water has a lot to do with your soil and the microbiome in that soil, most tress will need to have some water in the soil most of the time.
If a tree is living, it will be taking in water, no matter what you do to it; prune, coppice, pollard, espalier, etc. if it is living it will need water, so cutting a tree back to give other trees water availability, is more one of those "Only on the internet" types of thing.

Depending on your latitude, you might be able to use moringa, a nicely growing tree that is one of the best sources of protein for humans that is available.
The moringa might work fairly well to your needs and it can also be coppiced.

Redhawk

Redhawk, Thanks for the bio tip - I'm in the Santa Cruz mountain foothills near San Jose, CA.  I want to create permanent parallel fencing for a Silvia-pasture set up and use perpendicular temporary fencing to create a paddock shift system.   Currently, I have goats, but the fence should work for goats, sheep, pigs, and cows.  I was told that Morgina wants really sandy soil.   I do have a lot of live oaks on the less steep parts of the property.  My understand is that this land was logged about hundred years ago and my guess is that when the trees went so did the topsoil and they haven't been able to re-establish themselves on the steeper areas.  


One option, may be alternating a fast growing, but water intensive tree with a slower growing more climate appropriate tree.  I should be able to turn the water off in a few years and use the fast growing trees (black orhoney locust) as posts while the slower trees (carob) start to get established.

I attached a satellite photo of the property as well as some picture of the land.