The genome assembly of Island Oak (Quercus tomentella), a relictual island tree species.

Island oak (Quercus tomentella) is a rare relictual island tree species that exists only on six islands off the coast of California and Mexico, but was once widespread throughout mainland California. Currently, this species is endangered by threats such as non-native plants, grazing animals, and human removal. Efforts for conservation and restoration of island oak currently underway could benefit from information about its range-wide genetic structure and evolutionary history. Here we present a high-quality genome assembly for Q. tomentella, assembled using PacBio HiFi and Omni-C sequencing, developed as part of the California Conservation Genomics Project (CCGP). The resulting assembly has a length of 781 Mb, with a contig N50 of 22.0 Mb and a scaffold N50 of 63.4 Mb. This genome assembly will provide a resource for genomics-informed conservation of this rare oak species. Additionally, this reference genome will be the first one available for a species in Quercus section Protobalanus, a unique oak clade present only in western North America.