Quantitative evaluation of plants on top surface of the Great Wall in Dazhuangke using the analytical hierarchy process

The Great Wall of China was a military facility that has been continuously built and used for over thousands of years, and is a world-renowned cultural heritage site today. The plants growing on top surface of the Great Wall caused the damage of the Great Wall, but the process of removing these plants may further damage the body of the Great Wall. In this paper, based on the Analytic Hierarchy Process and the expert Delphi method, we selected 13 specific indices from three Constraint Layer factors, and then estimated and identified 45 species/categories of plants on top surface of the Dazhuangke section of the Great Wall. The results showthe constitution and the evaluation gradeof the evaluation system. The factor of Disruptive Effects plays the main guidance role in the evaluation system of the Constraint Layer; The indices of Impact on the Near Side Wall is the core element of the evaluation model with the highest weight of the Standard Layer. And the “Preservation”, “Partial Preservation”and “Removal” recommendations were given based on three evaluation grade (from Grade I to Grade III). This research provides scientific basis for the protective repair of the Great Wallheritage as well as "Garden on the Great Wall".