The Identification of Historic Plant Landscape Characteristics and Conservation Strategies for Longevity Hill Based on the WSL Monoplotting Tool

The surrounding environment of architectural heritage sites is integral to cultural heritage protection; plant landscapes play crucial roles in them. Controlling plant spaces and appearances is essential for preserving plant landscapes. A World Cultural Heritage Site, the Summer Palace has undergone multiple changes since the 1860s; restoring and protecting plant landscapes has been an ongoing research focus. However, data accuracy limitations have hindered analyses of the overall spatial characteristics of historical gardens. Here, the historical dynamics and unique landscape features of plants on the front hill of Longevity Hill (FLH) are explored, and conservation and renewal strategies are proposed. Geographic information system (GIS) and WSL Monoplotting Tool are used to identify historical plant spaces. Plant space types are classified, and their landscape characteristics are analyzed. On the basis of historical events, the historical plant spaces on the FLH can be divided into two major categories and six subcategories. The vegetation retention area (south side) was less affected, and the plant landscape along Kunming Lake was the most well-preserved. However, the vegetation-damaged area (north side) was impacted more in the western part than in the eastern part, with notable changes in spatial landscape characteristics, particularly regarding forest function, morphology, and structure. Strategies are proposed for reducing human intervention and adjusting retention areas; furthermore, historical images and spatial grading in damaged areas can be used to suggest landscape adjustment and restoration strategies. This study introduces a method for analyzing the historical characteristics of plant landscapes over time that can be used to protect cultural heritage sites worldwide.