A Thousand years ago the mountains of the Hijjaz and Asir were much more densely covered with woodlands with only remnants, estimated at 2.7 million hectares, still remain in the remote inaccessible areas.
Juniper woodlands are one of the few densely wooded habitats in Saudi Arabia. they thrive at altitudes of 2000 - 3000 meters, and are characterized by some of the highest species diversity and biomass in Saudi Arabia. They are important for the production of orographic rain and for the preservation of soil integrity. They are also the biotope most favored by Saudi citizens for the nature related tourism.
A dieback phenomenon has been reported in the junper woodlands of Arabia and is a matter of concern. Available evidence indicated hydrological and/or climatologically cause.
There are also olive woodlands on slopes that are 1500 - 2000 meters high that contain a number of other species. In addition to the mountain woodlands there are the arid woodlands , which are primarily acacias scattered nationwide in lower altitudes.