I have enough hazel poles growing, so I decided to use that, rather than the iron hoops they provide, so as to save £200, to be able to adapt to the slope of my land, and because I can.
Here's how it is done:
Next, stick them in the ground, bend them over and lash them together with baling twine (I have made up a song about baling twine). Don't worry if it is a bit wobbly, it gains rigidity from the covering.
Split a felled tree trunk into 4 (I used sycamore because it was already down. It took about 2 minutes to split it. (Don't even bother to think about splitting cherry - that takes more like 2 days).
Use an adze to trim the wood. This takes a very long time but it is deeply satisfying. This makes to door frames (see above).
Ignore any rabbits that offer to help. They are unreliable.
Et voila. Robert, as the French say, is votre oncle.
That's my younger son Laurence in the doorway.
See Frugal in Cornwall to read more of this kind of stuff.