【目的】江南园林假山是园林遗产的重要组分。植物根劈现象广泛存在于各遗产园林之中,严重威胁着假山遗产的长久保存与发展。作为假山安全与保护的影响因素,将植物根劈现象纳入假山预防性保护体系,能够为假山预防性保护体系的构建和完善进而有效开展园林遗产保护提供依据。【方法】以南京瞻园为例,对假山受植物根劈的作用机理进行量化分析,总结南京瞻园假山现状中的问题树种,提出并验证了5个与植物根劈作用显著相关的植物变量,建立了有关植物根劈的裂缝面积回归预测模型。【结果】通过分析植物根劈现象的现状特征,认为直根系、深根系树种更容易导致假山裂缝问题,南京瞻园的此类树种中,朴树、女贞的根劈作用对假山的影响最为显著,枇杷、龙爪槐、广玉兰、木瓜的根劈作用次之。通过相关性分析发现,裂隙内根长、根径、植物冠幅、树高、基径是根劈作用的5种主要影响因子,与根劈作用产生的裂缝面积显著相关。其中,裂隙内根长、裂隙内根径与产生的裂隙面积呈正相关。通过多元回归性分析,初步构建假山裂缝面积预测模型,并设置相应的假山裂缝变化预警阈值,认为裂隙内根径不变而根长变化值超过11.25 cm时,即应考虑抑制单条根系的发育。【结论】植物根劈作用加剧了假山石体表面裂隙的发育和扩展,甚至有可能导致石体的断裂和山体的崩塌,严重威胁着假山遗产的长久保存与发展。根据量化分析的结果进一步筛选环境变量,划分监测等级并明确预警指标,可以提高假山遗产保护的预知能力和定量判断能力,达到及时预防、削弱植物根劈作用力并完善假山预防性保护体系的目的,为古典园林假山遗产的预防性保护工作提供参考。

【Objective】Jiangnan garden rockeries are a critical aspect of garden heritage. The widespread issue of plant root splitting poses a serious threat to the longevity and preservation of these rockeries. Incorporating the study of plant root splitting into the preventive protection system for rockeries can strengthen the system’s foundation, leading to a more effective preservation of garden heritage.【Method】This study uses the Zhanyuan Garden in Nanjing as a case study to quantitatively analyze the mechanism of plant root splitting in rockeries. It identifies problematic tree species, proposes and verifies five plant variables significantly related to root splitting, and establishes a regression prediction model for the area of cracks caused by this phenomenon.【Result】The study found that tree species with straight and deep roots are more likely to cause cracks in artificial rockeries. In the Zhanyuan Garden, the most significant root splitting was observed in Puja and privet, followed by loquat, Longjaya sophora, Magnolia, and papaya. Five factors,namely root length, root diameter, canopy width, tree height, and base diameter,were identified as highly influential in root splitting, showing significant correlations with the area of the resulting cracks. A multiple regression analysis helped to construct a preliminary prediction model for rockery crack areas, setting a warning threshold for changes in rockery crack dimensions. It was suggested that inhibiting the growth of a single root system might be necessary if the root length changes by more than 11.25 cm while the diameter remains constant.【Conclusion】Plant root splitting accelerates the development and expansion of cracks on rockery surfaces, potentially leading to stone fractures and structural collapse, thus endangering the heritage’s long-term preservation. Based on the quantitative analysis, refining environmental variables, categorizing monitoring levels, and defining clear warning indicators can enhance the predictive capabilities and quantitative assessments for rockery protection. These measures aim to facilitate timely interventions to mitigate the impact of root splitting and improve the overall preventive protection system for rockery heritage.