城市绿地固碳释氧效益对植物群落特征因子响应分析

Analysis of the Response of the Carbon Sequestration and Oxygen Release Benefits of Urban Green Space to Plant Community Characteristic Factors

【目的】在城市自然地表破碎化程度加剧的背景下,在现有的城市环境和资源限制下最大化植物群落固碳释氧效益,是缓解城市气候变化问题、响应“双碳”目标的关键途径之一。【方法】以天津市典型百年城市公园——人民公园为研究区域,选取60个典型植物群落,分别测算日固碳释氧量,分析植物群落典型特征因子(层次结构、平均胸径、平均树高、平均冠幅、三维绿量和群落密度)与固碳释氧量之间的关系。【结果】研究表明:1)层次结构越复杂的植物群落,固碳释氧能力越强;2)具备特定规格的植物群落(平均胸径为0~0.2 m、平均树高<6.0 m、平均冠幅为0~2.0 m)具有更强的固碳释氧能力;3)0.2~0.4株/m^(2)是实现群落高固碳释氧效益的最适种植密度区间;4)各植物群落特征因子中,三维绿量对固碳释氧效益的正向影响最显著。并进一步提出提升植物群落固碳释氧效益的优化设计策略。【结论】探究植物群落特征因子对固碳释氧量的影响可为城市绿地高固碳释氧能力的植物群落设计提供理论支撑与指导。

[Objective]With the rapid expansion of urbanization,activities such as population growth,changes in land use,and extensive use of fossil fuels have led to significant CO_(2) emissions,resulting in a series of climate issues such as global warming.Plant communities,through photosynthesis,act as the only natural carbon sink in urban areas,holding crucial significance for mitigating climate change.In urban environments,the configuration of plant communities is influenced by intrinsic factors such as species composition,tree size,and community structure,as well as external factors such as site conditions and anthropogenic disturbances.The limited space in urban areas further constrains the unrestricted expansion of urban green spaces.Therefore,optimizing the planting of urban plant communities to maximize carbon sequestration and oxygen release under current conditions is one of the key approaches to mitigating urban climate change issues and achieving the“carbon peaking”and“carbon neutrality”goals.[Methods]This research focuses on Tianjin People's Park,a typical century-old urban park in Tianjin,and selects 60 representative plant communities.The photosynthetic rate was measured using the FK-GH60 photosynthesis meter,while the leaf area index was determined using the live leaf area meter YMJ-D and the LAI-2200C canopy analyzer.Based on the obtained data,daily carbon sequestration and oxygen release data for each plant community are calculated.Hierarchical structure of plant community,average diameter at breast height,average tree height(DBH),average crown width,three-dimensional green biomass,and community density are selected as plant community characteristic factors.Pearson correlation analysis is performed using SPSS software to analyze the correlation between plant community characteristic factors and carbon sequestration and oxygen release capacity.Furthermore,principal component analysis of plant community characteristic factors is conducted using SPSS software.[Results]The average carbon sequestration and oxygen release capacity of different plant communities can be ranked from high to low as follows:Arborshrub-grass,arbor-grass,arbor-shrub,shrub-grass,arbor,and shrub plant communities.There exists a highly significant moderate positive correlation between the average DBH and carbon sequestration and oxygen release capacity of plant communities(r=0.574,p<0.01).There exists a highly significant strong positive correlation between the average tree height of plant communities and carbon sequestration and oxygen release capacity(r=0.631,p<0.01).There exists an extremely significant strong positive correlation between the average crown width and carbon sequestration and oxygen release capacity(r=0.852,p<0.01).There exists an extremely significant strong positive correlation between the three-dimensional green biomass of plant communities and carbon sequestration and oxygen release capacity(r=0.844,p<0.01).There exists a highly significant positive correlation between plant community density and carbon sequestration and oxygen release capacity(r=0.681,p<0.01).Based on this,the research further proposes optimization design strategies to enhance the carbon sequestration and oxygen release benefits of plant communities.This research draws the following results:1)The more complex the hierarchical structure of a plant community,the stronger its carbon sequestration and oxygen release capacity;2)plant communities with specific specifications(average DBH:0-0.2 m;average tree height:below 6.0 m;average crown width:0-2.0 m)have stronger carbon sequestration and oxygen release potential;3)0.2-0.4 plants/m^(2) is the optimal density range for achieving high carbon sequestration and oxygen release benefits;4)among various plant community characteristic factors,three-dimensional green biomass has the most significant positive impact on carbon sequestration and oxygen release benefits.[Conclusion]This research systematically explores the influence of different plant community characteristic factors on carbon sequestration and oxygen release benefits,identifies key influencing factors,and proposes optimization design strategies for plant communities,with a view to providing theoretical support and guidance for the design of plant communities with high carbon sequestration and oxygen release capacity in urban green spaces.However,this research also has limitations:1)Field research is concentrated during the period from August to October,lacking data from other seasons;2)in the process of field research,photosynthetic rates of plants in all sample plots fail to be measured simultaneously during the collection of some data,and the influence of surrounding ground cover on the results is not considered.Future dynamic and long-term monitoring of plant communities is needed to more fully understand their dynamic ecological processes.In addition,the influence of the surrounding environment on research results needs to be further considered to improve the scientific validity of the research.