Eucalyptus trees are a pest-resistant evergreen that produce good lumber and oil that wealthy elites in the \"wellness\" marketplace buy - they are also an invasive species. A new paper shows how scientists used CRISPR-Cas9 to knock out LEAFY, the master gene behind flower formation, so the trees will not reproduce sexually. The greenhouse study involved a hybrid of two species, Eucalyptus grandis and E. urophylla, that is widely planted in the Southern Hemisphere; there are more than 700 species of eucalyptus, most of them native to Australia. \"Eucalyptus is one of the most widely planted genera of forest trees, particularly the 5.7 million hectares of eucalyptus in Brazil, the 4.5 million hectares in China and 3.9 million hectares in India. Though there is no \"foreign\" DNA in the tree, it would still be illegal to plant, even though Brazil has huge amounts of eucalyptus tree farming.