The daggerleaf tree was a type of plant created via genetic engineering in a joint effort by the Kazarites and the Payav. They had narrow, succulent leaves which retained water, and deep roots which could tap water deep below the surface.
A forest of daggerleaf trees were planted on the edge of the Jarol Desert on planet Kazar prior to 2279, where they served as a windbreak and prevented further erosion of the land where a community of Payav refugees had settled. By 2283, following the return of Raya elMora to power on Mestiko, forests of daggerleaf tress were also planted on that planet. (TOS eBook: The Darkness Drops Again)