Purpose : beauty, environmental, shelter for the livestock from sun (and flies) in summer, and from rain, wind and occasional snow in winter.
The idea would be to trim on a four-year cycle, one quarter of each length each year, so that there are always some older stems for wildlife and for shade / shelter, but we maintain the hedgerow within its bounds.
After discovering that there is a whole scheme to reintroduce hedgerow trees, I guess we will have some trees being trees (probably pollarded, not least because it's so windy here) as well as the main hedge.
The ground is clay, and in some parts the soil is really not very deep (as it's slid down the hill over the years!)
The hedgerows will be stock-fenced where grazed (or electric fenced when stock are in), some will be open on the other side if not grazed, including alongside tracks that we use for moving animals. But it's small numbers - 2 cows with calves, up to 20 sheep. The cattle can be haltered if need be.
Some choices are obvious but I am looking for suggestions and advice / experiences, please.
I personally have a distinct anathema to non-native species, but it may be that we should consider one or two to meet specific requirements. (Eg., evergreen to provide shelter in winter.)
The hedgerow
Hawthorn of course.
Blackthorn : NO, I am fed up of the damage the thorns do to sheep's feet. We have plenty of hedgerows around here with it as the main ingredient, so we shan't be short of sloes
Holly? I would love there to be some sections that are evergreen so that there is a bit better protection for the sheep and ponies in winter. (And I have read tonight that holly next to the trees which are allowed to be trees would be a good plan, as they are shade tolerant.)
Other evergreens you can suggest? We aren't going to trim enough to do it with beech or hornbeam (they only keep their leaves on over winter if you trim religiously and closely every year, which doesn't sound like us at all

and it is hellish windy where most of these new hedgerows are going.)
Hazel - any cons? (And advice on two types that can fertilise each other, please! Or does that just happen when you order it?)
Elder no good on clay?
Beech - probably would take on the lower ground where the soil is deeper, but not higher up where the soil is shallow. It would be great to let some grow for firewood and cut trunks for firewood on a 10 year cycle. So maybe should be in the 'tree' section.
Guelder rose? Dog rose? Rosa rugosa? All three?
Field maple? Is a bit of a marmite tree, I think? Any benefits?
Crab apple?
Dogwood? Not toxic as far as I can see, and has pretty red stems in winter...
Any other trees that will perform okay with a 4-yearly trim, and have benefits?
Not sure if they would be trimmed hedge or need to be trees
Goat willow? The ground is very wet, so I wonder about having some goat willow to help with that. If it wouldn't cope with regular (4 year) trimming, we could put it in sections where we are letting a tree or two grow? (
Other thread specifically about willow as a hedging plant.)
Wild cherry? Wild pear? Damson? Any other fruiting trees that would work in the trimmed parts?
Trees, whether pollarded or not
Not ash at the moment

Elm, I read something that said to plant elm and to pollard before they reach 20 years old, when the bark beetle strikes. It would be nice to help elm recover but I think it might be better to wait until there is more of an established process. The Cornish Elm is much missed so I expect there will be a scheme to reestablish once they understand how to manage them.
Willow! Which I think we would pollard and use the stems.
Holly under the other trees, as shade tolerant. And would then provide shelter in winter as the holly is evergreen.
Beech to be pollarded on a 10-year cycle for firewood. Nearer the bottom where the soil is deeper.
Oak. I think it's too windy and the soil too shallow, except maybe the very bottom, more sheltered section.