Anthropogenic factors also play a role in the disturbance of grasslands.[1] Degradation has been shown to appear when humans move into such areas to build, for example, roads or settlements.[2] Roads reduce the area, in which grass can grow successfully; and the settlements constructed by herdsmen have proven to be the most damaging to grassland, since they are accompanied by their animals who further harm the region. Also when humans convert natural grassland into farmland, they often harshly farm it by repeatedly planting the same crops year after year and by having to do this, the soil quality is lowered when these crops suck the nutrients out of the ground.[3] When the farmer is finally done with the land, it is in extremely poor condition for grass to grow.[4] Another cause of degradation by man is deforestation.[2] When these trees are demolished and taken away, the soil lacks the strong root system formerly contributed by trees; therefore, the soil is upturned, cannot support plant life as well, and is more susceptible to landslides.[2] Gathering of medicinal plants, particularly in China, also contributed to a certain extent to degraded grasslands, but this practice is not done as frequently anymore.[2]