**5. Natural vegetation**

It is one of earth's most vital natural resources that provide food, fiber, and fuel for the sustainability of human life, while vegetation preserves biodiversity and soil and plays an outstanding role in the hydrological cycle. The inhabitants of the arid region of Pakistan have cleared the land surface by cutting the natural vegetation cover for the cultivation of crops. While the vegetation cover controls the soil erosion, storage and filtration of water, and wildlife habitat, playing a key role in the transfer of gasses between the atmosphere, soil, and water bodies is basic to the crop cultivation, production, and growth.

Dense forests can influence the local climate to some extent. Temperature is lower in a region of dense forests, light is reduced greatly, and the soil is several degrees colder. Humidity is greater, and dew and fog are formed readily over the adjoining fields. Evapotranspiration from the soil and wind velocities under a forests covered area are greatly reduced and also increase the capacity of water storage of the soil. The barren land and mountains have inverse climate condition.

In arid region, there is a variety of natural vegetation due to variation in climates, topography, and soil condition. "Natural vegetation covers about 4.8% of the total area of Pakistan, while about 20–25% of forests are needed for the balanced economy of a country" [3]. The province-based distribution shows that Khyber Pukhtunkhwa has the leading percentage (15.6%), followed by Sind (2.1%), Gilgit-Baltistan (13.5%), and Azad Jammu and Kashmir (13.6%) and the remaining 55.2% in Punjab and Baluchistan province. The arid region has two distinct types of forests, that is, natural vegetation and the plantation forests (**Figure 4**).

The natural vegetation consists of different type of forests including alpine forests, coniferous forests or subtropical pine forests, subtropical dry forests, tropical thorn forests, and coastal mangrove forests. Plantation forests are divided into riverine and irrigated forests that are located at the roadsides, canals, and rivers.

**Figure 4.** *Natural vegetation of the arid region, Pakistan, Khan [3].*
