城市绿地碳循环过程机制与系统特征综述

A Review of Process Mechanisms and Systemic Characteristics of Urban Green Space Carbon Cycling

关键词:  风景园林  城市绿地  碳循环  理论框架

Key words:  landscape architecture  urban green space  carbon cycling  theoretical framework

摘要:

城乡建设领域低碳发展是达成“双碳”目标的工作重点，城市绿地作为具有碳汇与碳排双重属性的生态基础设施，在提升城市生态系统碳汇能力方面有 着关键的作用。基于多学科交叉视角，系统梳理了城市绿地碳循环的组成要素、过程路径、概念定义，构建了由植物、土壤、水资源、人工构筑(建材)构成的多 维碳库系统，解析了其“垂直-水平”“自然-人工”双维碳通量路径与“碳流-能量流-物质流”系统耦合关系。在此基础上，提出城市绿地碳循环的三大核心特 征：时间尺度上的周期动态性、系统运行中的外部依赖性及多功能目标下的协同权衡性，进一步推导了运营碳排占比高、外部依赖性强、多目标权衡难的约束条 件。结合研究及实践视角提出了城市绿地低碳建设的未来展望及主要着力点。

Abstract:

Low-carbon development in urban and rural construction is a critical priority for achieving China's dual carbon goals of carbon peak and carbon neutrality. Urban green spaces, as ecological infrastructure with dual attributes of carbon sinks and carbon sources, play a key role in enhancing the carbon sink capacity of urban ecosystems. To understand the research landscape, this paper uses CiteSpace to conduct keyword co-occurrence and cluster analysis on related studies from 2010 to 2025. Chinese research focuses on carbon storage, low-carbon landscapes, and spatial distribution, while English research emphasizes carbon sinks, soil organic carbon, blue carbon, climate change mitigation, and ecosystem services. Current studies can be organized into a four-scale hierarchical framework ranging from microscopic components to single green space patches, urban green space systems, and regional ecosystems. This framework integrates three interconnected research components: internal mechanisms, quantitative analysis, and strategic systems, forming a closed-loop research system. From a multidisciplinary perspective, this paper systematically reviews the components, pathways, and definitions of the urban green space carbon cycle. A multidimensional carbon pool system is constructed, consisting of four interconnected pools: vegetation, soil, water resources, and artificial materials including building materials and structures. The paper then analyzes the dual-dimensional carbon flux pathways, namely the vertical-horizontal pathway and the natural-artificial pathway, and reveals the highly coupled system relationship among carbon flow, energy flow, and material flow. For each carbon pool, the paper reviews the current research focus and carbon cycle processes. For the vegetation carbon pool, studies focus on spatial structure, community composition, and tree species functionality, with high-density mixed forests and high-carbon-sink tree species lists being key topics, though the latter have strong regional limitations. For the soil carbon pool, research examines the effects of temperature, moisture, root systems, and vegetation biomass, showing that soil carbon storage in urban green spaces is roughly three times that of the vegetation carbon pool. For the water resource carbon pool, which includes natural water bodies and artificial waterscapes, studies focus on carbon sequestration through solubility pumps and biological pumps, as well as methane emissions from wetlands. For the artificial material carbon pool, research emphasizes carbon emissions from material production and transportation, with localized emission factor databases being developed. Energy supply is another major source of carbon emissions throughout the full life cycle of urban green spaces, including construction, operation, and maintenance. Based on this framework, three core characteristics of the urban green space carbon cycle are proposed. The first characteristic is periodic dynamics on the temporal scale, meaning that carbon sequestration and emissions vary regularly over time, with notable diurnal and seasonal patterns. The second characteristic is external dependency in system operation, indicating that urban green spaces rely heavily on external inputs of materials and energy as well as artificial interventions such as irrigation, fertilization, and pruning. The third characteristic is the synergy and trade-off under multi-objective goals, where carbon sequestration must be balanced with other ecosystem services such as recreation, aesthetics, ecological safety, and cost control. Looking forward, this paper identifies key priorities for low-carbon urban green space development. Future research should bridge disciplinary fragmentation across landscape architecture, ecology, forestry, and building science to establish a systematic methodology. Practice urgently needs top-level design guidance including carbon accounting standards and low-carbon maintenance specifications. As research advances, the low-carbon transformation of urban green spaces will help achieve the dual carbon goals with high quality.