基于LCA的城市绿地管养对环境影响的量化方法探讨

城市绿地是重要的绿色基础设施。城市绿地要实现设计目标，保持长久的景观效果离不开持续不断地养护管理，同时管养工作又会带来物资消耗和废弃物排放，对环境造成负面影响。基于生命周期评价方法(LCA)，以资源能源消耗和气候变暖潜值作为对环境影响的主要因子，将城市绿地划分为乔木、灌木、地被和草坪层，建立了管养对环境影响的量化模型。以郑州市郑东新区绿地为研究对象，选取34个植物群落(20m×20m)为样本进行了验证，计算得到各植物层管养资源能源消耗和气候变暖潜值特征量以及管养工作标准化加权环境影响指数。结果表明，乔木的管养环境影响指数最低，比群落均值低32%；施肥和垃圾清运是环境影响的主要因素，占群落管养环境影响指数均值的75%以上；与农林业相比，城市绿地管养环境影响指数处中低水平，但资源能源消耗因子的影响指数偏高。基于LCA方法的研究结果可以为城市绿地设计和精细化管理提供量化参考。

The Quantitative Research of the Maintenance Environmental Impacts in the Urban Greenspace Based on LCA

Urban greenspaceis an important green infrastructure. Maintenance is a major task to keep the designed function and landscape effect of greenspace, and it can lead to the material consumption and waste discharge in simultaneously. This essay divides the plant community into woodland, shrub, herbaceous and grassland layers, builds up a quantitative model of the maintenance environmental impact (MEI) in the urban greenspace in using the Life Cycle Assessment (LCA). The quantitative model takes the energy consumption and global warming potential (GWP) as the environmental factors. After quantifying the energy consumption and GWP characteristic data of plant layers of the 34 plant community samples (20m×20m) in CBD area of Zhengdong New District, the environmental impacts index shows the woodland plants owned the most maintenance environmental efficiency, and its MEI exponential value was 32% lower than the average value of plant communities. Fertilization and pesticide spry are regarded as the major maintenance tasks leading to the environmental impact, and their total MEI value occupied the 75% and more than the average value of plant communities. Compared with the LCA research in agricultural & forestry area, the MEI in urban greenspace maintenance was lower than the average values, except for its energy consumption value was higher than the average values. In summary, this quantitative model can be reference for the delicacy and sustainable management of urban greenspace. Keywords: landscape architecture; urban greenspace; life