Kona Tree is a tree located in Jaya and in other areas. It first appeared in Chapter 288 and Episode 187. It is a tall tree with a thin trunk and thin, leafy branches. Within this tree is a substance known as Conine, which is necessary to cure the Tree Fever disease. The Conine was used by Montblanc Noland to treat the infected Shandia people. The trees were regarded by the Shandia as locations for there ancestral spirits to reside in. When they were chopped down to cure the Shandia's Tree Fever, the Shandia and Noland's relationship was severely damaged, causing the botanist to leave Jaya.
SBS Volume 32 confirmed Conine(コニーネ) is actually Quinine(キニーネ) with a mistaken vertical stroke in the first character; an alkaloid found in the Cinchona genus of plants, which is used to treat diseases such as malaria and babesiosis.
Interestingly, a chemical known as Conine does in fact exist; an alternate spelling for the poisonous alkaloid in Conium maculatum, also known as poison hemlock.