Hey there, fellow permies.
I was planning out
hugelkultur bed today, and thought I'd share two great resources I've been using with you folks here.
This is a list of
trees with known allelopathy to avoid.
http://warnell.forestry.uga.edu/SERVICE/LIBRARY/index.php3?docID=160&docHistory%5B%5D=2
Anything in the "slightly" category
should be fine, but even a little moderate or strongest could work.
Geoff Lawton has said in an interview having some allelopathic woods mixed in can lead to more diverse soil life.
I like that they cite sources.
This site is one I used more as a woodworker, but could be useful in
hugelkultur.
http://www.wood-database.com/
It has information on things like hardness, rot resistance, toxicity to people, density of different woods.
I hope someone finds use from them.