Thesis (Ph. D.)--University of Washington, 1983. / Vita. Bibliography: leaves [302]-308.

Thesis (master's)--Jāmiʻat Umm al-Qurá. / Includes bibliographical references (p. 307-320).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1972. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

This practical thesis aims to reform the use of plant material in landscape architecture projects in the Najd or Central Region of Saudi Arabia. Many aspects of landscape architecture in Najd attempt to emulate western concepts. Neglect or unawareness of the values of Arabic society is one of the main reasons for the failure of the landscape programme. This factor of traditional culture is particularly sensitive in Najd which is the birthplace of Whabism, one of the strictest applications of Islam. This implies special conditions that made outdoor design sensitive and complicated, unable to tolerate western forms. Western urban patterns in planning, such as wide streets, neighbourhood parks and their detailed components of artifacts and plant materials, all shattered the character of traditional landscape architecture in the region. Although indigenous landscape elements in Najd evolved as a result of socio-environmental factors, many consultants do not differentiate between Persian, Islamic, and Najdi gardens. The inventory of available plant species indicates that most are imported from tropical and subtropical countries. These species require stripping of soil from wadi Hanifah for potting, and for top soiling planting projects, a process destructive to the rich wadi habitat. Such a process is necessary when using imported plant material while native ones can adapt to the existing sandy and saline soil. The devastation of the wadi ecosystem, the saline water table and the high cost of maintaining those plants, represents serious short and long term economic, ecological and technical implications. These implications all point to the scale of these negative consequences of using imported plant material. Also, climatic data, points to the suitability and adaptability of native flora and its significance in avoiding further damage to eco-environment. Use of imported plants in arid Najd and creating a man-made micro climate to suit them, is a waste of resources, especially the water budget in Saudi Arabia. The thesis proves that these plants consume large amounts of water, require high levels of maintenance, are unsuitable to Najdi environment, introduce new pests and diseases, require special microclimatic conditions, rich soil and prove unsuccessful in their functions. All the previous factors combine to acknowledge the failure of many tropical gardens in the arid land of Najd. The answer lies in Najd itself which is wealthy in flora adapted to its local conditions. The potential for their use in Saudi Arabian landscape projects is vast. Individually they will substitute for the imported nursury stock, while the available communities represent a ready-made and complete landscape element which would be valuable for Najdi parks. The general question, the comparative advantages of native over imported plants is conclusively answered in the thesis. Though the native plants are diverse, attractive and available, they were tested practically aiming at, firstly to test the individual species, the "target species method", and secondly to test the whole community "target community method". Three test sites were allocated in the Diplomatic Quarter to test the selected target species and communities. The tests were conducted extensively over five years and intensively over three years, during which the author monitored closely a large number of species and communities and arrived at an encouraging set of results and findings. The conclusion of the thesis consists of two parts. Firstly, the successful species which is included in a Flora, and the successful target communities which use selected target communities as a landscape design tool. These are aimed specifically at landscape designers. Secondly, the author recommends how to utilize both methods in a typical Najdi urban park, and how to encourage their successful use.