Balanites aegyptiaca
In order to limit the environmental degradation of this conversion to agriculture, the sultan Tanimoune (1854–84) enforced laws to forbid the cutting of certain trees, with particular emphasis on the gawo tree (Faidherbia albida) with its fertilising properties: "He who cuts a gawo tree without authorization will have his head severed; he who mutilates it without reason will have an arm cut off." The sultan and later his successors also proceeded to plant trees, gawo trees in particular, and dispersed the seeds throughout the empire. Other protected trees were aduwa (Balanites aegyptiaca), kurna or magaria (Ziziphus spina-christi and Ziziphus mauritiana), madaci dirmi (Khaya senegalensis), magge and gamji (Ficus spp.). The fallow period for land at that time was six years.