For years I have been planting trees in expensive guards to prevent the sheep from eating them. More recently I have started planting large cuttings in cheaper plastic guards which seems to work quite well. But I should really have been going round with my eyes open as there was a kind of tree I have planted a number of now which the sheep just simply won’t eat. I had always assiduously planted them in the expensive guards, but I realised about three weeks ago that they probably didn’t need a guard at all (as they had hardly troubled the guards, so I planted one out just to see. Next day there was a tiny bit of exploratory nibbling, then nothing. This tree is going to grow tall in the middle of a sheep paddock without any guard at all. This is wonderful!
After 25 years this tree is over 10 metres (30′) tall, but there is foliage within 2′ of the ground!
The tree is the Bunya Bunya Pine (https://en.wikipedia.org/wiki/Araucaria_bidwillii) which once covered most of Eastern of Australia (before human burning almost made them extinct over the last few thousand years). They grow to be a large tree to 50 metres tall and produce huge cones up to a foot in diameter and 18 kilograms in weight – quite dangerous if they fall on you – full of tasty and nutritious nuts about the size of the first knuckle of your thumb. Underneath them is really great dry shelter for sheep. Their prickly nature (and abundant food source) also makes them a great wildlife habitat tree. Birds and possums nesting/roosting in them are pretty much safe from hawks and other predators. Our largest (nearly thirty years old now has been home to many creatures for many years. They can live for 500 years!
I suspect their relative, the Monkey Puzzle Tree (https://en.wikipedia.org/wiki/Araucaria_araucana) would perform the same service. They too are very prickly (as well as interesting) yield highly nutritious nuts & etc. Both are remnants of when Australia, Antarctica and South America were one continent, Gondwanaland. I have planted two of these over the years and both have died. I suspect they are (like Chestnuts) enormously susceptible to certain weedicides. A tiny drift from thistle spray will kill your chestnuts and this might have been what happened too to my Monkey Puzzles. I will get hold of some seeds (instead of live trees at >$50 each for my next experiment with them! You could try some of these guys https://bunyanurseries.com.au/ & http://www.natif.com.au/all-products/bunya-nuts,
https://australiangardener.net.au/product/bunya-pine-seeds/ – or keep your eyes out for a tree. One I planted 25 + years ago is big enough and old enough to have cones (they have two sexes on the same tree so do not need cross-pollination) but even though it is around 15-20 metres tall it has not produced yet. Maybe this year.
After three weeks, just a bit of nibbling to taste.
PS: I have also noticed that some of the solanums are not eaten by sheep (They are poisonous too), but they are also a dreadful weed and do not produce very good shelter except as a hedge.