基于“双碳”目标的城市绿化树种筛选及配置研究--以上海世博公园为例

Study on Selection and Collocation of Urban Greening Tree Species under Dual Carbon Goal-A Case Study of Sha nghai Expo Park

城市绿地系统是城市内唯一的自然碳汇,对大气中CO_(2)浓度的变化起到了不可忽视的作用。以上海世博公园为例,探讨不同群落类型、结构及其组成树种的碳汇能力,分析影响群落碳储量的关键因子。结果表明:调查样地内乔木17科27属30种,灌木和藤本植物28科51属62种,地被草本植物9种;2017年、2018年的总碳储量和平均碳密度分别为388.91 t、80.53 t/hm^(2)和399.82 t、94.08 t/hm^(2),公园内树种较丰富,碳储量逐年增加。以阔叶林或针叶阔叶林为主的乔木层与灌木层复层配置,阔叶树种与针叶树种混合配置,增加群落的固碳作用。单株碳储量依次为香樟(654.35±84.13 kg)、黄连木(631.47±52.53 kg)、榔榆(538.47±40.35 kg)、重阳木(435.50±62.25 kg)、榉树(386.76±36.83 kg);以香樟(25号、48号)为主要建群种的群落碳密度最高,香樟纯林、香樟+榔榆+枫杨、香樟+朴树+乌桕、香樟+榔榆的碳密度年增量较大。与群落配置相关的6个因子对群落碳密度贡献率从大到小依次为:乔木层树龄(31.44%)、种植密度(25.66%)、乔木层种类(11.95%)、配置结构(10.52%)、物种丰富度(10.50%)、立地类型(9.92%)。城市绿化中的植物群落配置应从树种、群落密度、群落结构等方面综合考虑,提升城市绿地碳汇效益和能力。

The urban green space system is the only natural carbon sink in the city and plays an important role in the change of CO_(2) concentration. Through a case study of Shanghai Expo Park, the carbon sink capacity of different community types, structures and components were discussed, and the key factors affecting community carbon storage were analyzed. The results showed that there were 30 species of trees belonging to 27 genera and 17 families, 62 species of shrubs and vines belonging to 51 genera and 28 families, and 9 species of herb. The total carbon storage and average carbon density were 388.91 t, 80.53 t/hm^(2)(2017) and 399.82 t, 94.08 t/hm^(2)(2018). The tree species of Shanghai Expo Park were rich and the carbon storage increased. The carbon sink capacity of the community was increased in the mixed configuration of broadleaved or coniferous-broad-leaved tree layer and shrub layer, broadleaf species, and coniferous species. Fine tree species for carbon sinking included Cinnamomum camphora(654.35±84.13 kg), Pistacia chinensis(631.47±52.53 kg), Ulmus parvifolia(538.47±40.35 kg), Bischofia polycarpa(435.50±62.25 kg), Zelkova schneideriana(386.76±36.83 kg). The community of the highest carbon density was C. camphora(No.25, No.48), and the larger annual increment of carbon density was C. camphora + U. parvifolia + Pterocarya stenoptera, C. camphora + Celtis sinensis + Sapium sebiferum, C. camphora + U. parvifolia. The contribution rates to community carbon density from high to low were tree age(31.44%), planting density(25.66%), tree species(11.95%), configuration structure(10.52%), species richness(10.50%) and site type(9.92%). Tree species, community density, and community structure should be considered during the plant community configuration. It can be improved the carbon sink efficiency and capacity in urban greening.