Originally, I thought there might be a connection between this inkwork and the tattoo Manson won as part of his Best Vocalist award at the South Florida Slammies on 3rd July 1994.
Why? Well the main Slammie Awards were ceramic skulls. But I now think the green skull was completed before then, perhaps even by late 1993. Which leaves Uncle Creepy
as his possible chosen tattoo for the Slammie bonus prize.
The tree tattoo, on top of the skull, gets a direct mention in Manson's biography. After his own sketch is used by someone he dislikes, he stakes his claim on the tree by having it indelibly marked onto his arm.
The tree - Manson's at least - was inspired by the Haunted Forest in The Wizard of Oz. Anyone ever notice that at one point the Cowardly Lion says, 'I do believe in Spooks, I do believe in Spooks...' (SPOOKS, get it?)