This song contains subject matter that may not be suitable for all readers as it deals with the topic of self harm/suicide.

In the Yamanashi Prefecture of Japan, right next to Mount Fuji, is a thirty-kilometer-wide forest known as Aokigahara, or the “sea of trees.” Despite the forest’s scenic beauty, Aokigahara is infamous for the number of suicides that happen there. Specific numbers are hard to come by but thousands have taken their lives there over the years with it becoming a notorious location referenced in films like The Forest, as well as books such as Nami no Tō (Tower of Waves), often reported as the novel that led to the trend. In 2012, the forest would become the topic of a short, emotional garage rock song by King Gizzard and the Lizard Wizard.

The title “Sea of Trees” was originally conceived as the band’s name. Stu recalled the story for Mess+Noise: “Just as King Gizzard was forming, Eric [Moore] went to a [Gareth] Liddiard show where he talked about ‘the Sea of Trees’ in Japan, a place where businessmen go to commit suicide. This actually ended up being our band name for a couple of our early shows and also seemed like a fitting title to this song.” In an interview for SYN radio, Joey mentioned their old name while noting how “morbid” it was. He brings up a “haunting” VICE documentary as a good watch. They abandoned the name due to it being “a bit too dark” and instead used it as a song title later on.
Originally “Sea of Trees” may have been called “Jam.” The band uploaded the song to the Flightless Soundcloud page on July 6th, 2012 with that title. Adding onto this, there’s an ASCAP ACE Repertory entry listed sometime before the release of Float Along — Fill Your Lungs, as well as a brief appearance on the setlist for 2012-05-09. That said, it’s unclear if these meant an early “Sea of Trees” or something else entirely. The song has a unique, haunting ending that cuts out quickly. According to the Mess+Noise article, it happened due to the band running out of tape. Interestingly, the lyrics to the verse have changed over time. "Sea of Trees" was released as the penultimate track of 12 Bar Bruise on September 7th, 2012. Original pressings of 12 Bar Bruise, as well as the 2023 reissues, have liner notes featuring a drawing of a tattooed man. On these, we see the original final line “and when you’re feeling suicidal, some times you just have to end it.” For the 2018 reissues, however, there were new liner notes. These replace the original line with “and when you’re feeling suicidal, sometimes you just have to unfold” — making it noticeably less dark. According to Joey before a performance of the song on 2022-10-11, “Sea of Trees” is Lucas’s favorite Gizzard song.