I understand that alleleopathic woods are not best for most Hugel situations. What if I char/burn the cyprus I just cut on my land? Is it then alleleopathic cyprus or good charred wood (for Hugel base)? Thank you so very much for your insight and willingness to share knowledge!
As long as you turn the cypress into charcoal you would have no worries about any issues.
One thing to keep in mind about most Allelopathic trees.
They only exude these compounds from their root system and the leaves accumulate the compounds just before leaf fall so that there won't be early competition come spring.
Usually the actual wood of the tree, both trunks and branches, has the least amount of allelopathic compound concentration.
Cedars are a good example of this, while alive the roots exude allelopathic compounds so there is little competition for water and nutrients near them.
When needles fall, the compounds leach into the soil, re-enforcing the alleopathy.
If you cut down the tree and remove the sap wood, the heart wood has very few and almost negligent amounts of the allelopathic compounds.
Cypress trees are in the same family as the "common" cedars which are both members of the cupressaceae family.
The red hearted cedar is in the juniperus genus which is part of the cupressaceae family, so their characteristics will be similar.
I have used cedars in hugel structures with out any adverse effects on the plantings, Cypress should be close enough that as long as that resin containing sap wood is stripped off, you should get similar results.