Ysalamiri on olbio trees.
The ysalamiri subsisted on the leaves of the olbio tree, which is why they were generally found living within these trees. The planet Myrkr hosted a forest abundant with olbio trees; however, the species rarely survived relocation off-world, or any kind of transplantation. Despite this issue, scientists hypothesized that the trees had, at some point, been transplanted from Mandalore, a theory stemming from the significant levels of Mandalorian iron discovered within their structures. Furthermore, it was speculated that the ysalamiri's remarkable Force-dampening ability was a direct result of their consumption of large quantities of Mandalorian iron. Talon Karrde maintained a substantial olbio tree, populated with ysalamiri, at his Myrkr-based headquarters.
The olbio tree first made its appearance in Heir to the Empire by Timothy Zahn, but its official name wasn't established until much later, in Troy Denning's The New Jedi Order: Star by Star.