posted 2 years ago
When you say 'they died', are you talking about the existing old hazel plants, or the new stem cuttings that you tried to plant by the ducks?
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When pruning back an adult tree for any purpose, including coppicing, you never want to remove 1/3 of the branch mass at a time. (Like, within the same season) - if you want it to live.
If the old hazel haven't been coppiced in over 5 years, and you tried cutting them down to the base.... yeah, I bet that'd kill the poor things. Most adult trees have a rough time surviving being cut down.
When starting from an adult tree, even if it had been coppiced a decade ago, you have to get it used to putting out young branches from lower on the trunk, before you can cut the trunk down lower.
This means cutting a couple big branches down each year. After several years, all of the upper branching should be gone, and you're left with a trunk that has young branches growing out of it.
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Re-reading your post, I'm not certain we're using the same terminology.
Coppicing is the technique of taking a young, already-established tree and cutting it down every 3-5 years, so that it puts up new branches as 'trunks'.
A 'coppice' is a plant on which coppicing has been done.
If you want to start a 'coppice' of hazel by your ducks, you first have to propagate your hazel, and just... plant hazel. Get an established hazel plant growing first.
You aren't starting a coppice at first, you're just starting a new plant.
You can't really coppice it until after the plant has been established for a few years. It NEEDS a lot of strong, healthy roots to survive being cut back.
So... start by getting hazel or willow trees growing in those spots. Don't worry about coppicing until those plants are rigorously growing.