The Central Highlands: This is the mountainous portion of the West Bank including east Jerusalem. This region is approximately 3500 square kilometers in area and 120 kilometers in length. Elevation reaches slightly more than 1000 meters above sea level (in Halhul -Jabal Naby Yunis-1020m) -Hebron area. Average annual rainfall ranges from 400 to 700 millimeters. Most of SP’s natural and planted forests are located in this area. Agriculture depends on rainfall.
The Semi-Coastal Region: This area, located in the Jenin, Tulkarm and Qalqilya districts, is an extension of land inside the Green Line (the 1967 borders). It is 120 square kilometers in area and has an average annual rainfall of 600 millimeters.
The Eastern Slopes: This area runs from Jenin in the north to Hebron in the south. It is often referred to as the “Jerusalem wilderness.” Traditionally, this was the winter grazing area for native sheep; shepherds used to move their flocks there during winter due to the moderate climate and grazing pastures. The eastern slopes are also home to most of wild mammals and much of its native flora. The area is under substantial development pressures due to Israeli occupation activities (e.g., intensive building of colonial settlements and associated roads and related activities).
The Jordan Rift Valley: This is a unique area that lies east of the West Bank highlands, between the eastern slopes and the mountains of Moab in Jordan. A semi-arid region with mild to warm winters and hot dry summers, it is a continuation of the African Rift Valley. Israel occupying power has expropriated much of this zone’s land for illegal colonial settlement activities, and Israeli settlers practice intensive agriculture in this area. Many winter crops for export are planted using irrigated open and greenhouse agriculture. This region falls along bird migration routes, which is considered the second most important flyway for migratory soaring birds in the world and is the foremost route among Europe- Africa flyway.
The Coastal Zone (Gaza Strip): This is the coastal zone along the eastern Mediterranean. The area has one of the highest population densities in the world, with the bulk of the population being refugees from 1948. Some migratory birds land in Gaza to rest and feed in route from Africa to Europe or vice versa. Excessive pumping of aquifers and the resulting saltwater intrusion has caused a dramatic increase in the salinity of water resources. Added to this is an increase in nitrate levels, thought result from leaching from sewage and the use of nitrate-based fertilizers within and outside Gaza. Aquifer recharge largely depends on rainwater flowing underground from the Hebron hills and west.
Based on the geographic distribution of plant species5, these regions divided as follow
The Mediterranean region: Extends along the coastal plain to the north of Gaza Strip, the central highlands, and the northern part of the Jordan Rift Valley and the western slopes of the Nablus and Jerusalem and Hebron Mountains, ending 65 kilometers south of Jerusalem. Its boundaries with the adjoining Irano-Turanian territory cannot be drawn with exact precision because humans, over many millennia, have caused heavy damage to Mediterranean territory vegetation. As a result, plants from the adjacent territories penetrated and extended into this area, resulting in a fairly broad belt of mixed flora and vegetation. The climate of this area is typical of the Mediterranean region, with a minimum annual rainfall more than400 millimeters. It is covered with vegetation includes forests, maquis, garigue (dwarf shrub formations) in which Quercus calliprinos Webb; Pinus halepensis Mill; and Pistacia palaestina Boiss are shown to be the dominant species. The local forests and maquis can be grouped as the Common Oak Forests, the Aleppo Pine Forests (Pinus halepensis Mill.); the Carob (Ceratonia siliqua L.); Mastic Pistacia palaestina Boiss and P. lentiscus Scrub Forests.The plants of this area have the largest number of associations and are found mainly on terra rosa soil and, to a lesser extent, on rendzina and consolidated sandy soils or sandstone.
The Irano-Turanian Region (Oriental Steppe): This region consists of a narrow longitudinal belt to the east of the Mediterranean area. It covers the southern parts of the West Bank (the Jerusalem and Hebron wilderness, central Jordan Rift Valley and adjacent steppes and rocky areas facing the southern part of the Jordan Rift Valley). Annual rainfall ranges between 150 and 300 millimeters. Its dominant soil types are gray calcareous steppe and loess soils. Due to low rainfall, rain-fed cultivation is untenable except in the depressions. This area is composed of different associations such as the Zizyphetumloti association, the Retameto- Rhudetum association and the Seriphidium herba-alba (Asso) Soják; association in which Zizyphus lotus, and Retama raetam (Forssk.)Webbis the most common members of these associations respectively.Plant cover consists of steppe desert, thorny and broom-like brushwood and dwarf shrub communities. Trees are rarely associated with this area.
The Saharo-Arabian Region: The Saharo-Arabian region is characterized by large expanses of gravels, curcar, salines, and sand dunes along with `the complete lack of cultivation, except for a considerable number of seasonal plant communities in and around springs and some trees near frequent water resources. Annual rainfall ranges between 50 and 150 millimeters.
The Sudanese Penetration Region: This region is a transitional zone between the Sudanese area and the Arabian Desert. Its high winter temperatures support the growth of many Sudanese species in the Dead Sea area and south of the Jordan Rift Valley. Dominant with some plant associations such as Haloxyletea saliconici (Phoenix dactylifera L.) and Acacitea tortilis (Ziziphus spina-christi (L.) Desf.and Vachellia tortilis (Forssk.) Galasso & Banfi.Plant cover is restricted to oases, with some plant associations being similar to those of the African Savanna.