I used Walnuts and Sumac for many a year.
When I do dye nowadays, I use logwood powder.
Over the years, I learned a light coat of rust and dying wasn't nessasary (every year) as long as I boiled in Lye (to clean odors) and wax before each season. A clean, waxed trap is odorless. I do re-dye my traps every 3-5 years.
Back when I dyed every season (dye one day, waxed the next day) I noticed my newly 'dyed' traps rusted slightly over night! Dang, I just dyed 'em yesterday! But still waxed with no problems. I tested four dozen NEW canine traps by just boiling oil film off and waxing then setting. Those traps had no ill effect on Canines. So now I just 'dye' once in awhile more for tradition than protection.
Am not trying to change anyones methods, just stating how I do it, nowadays.