Is Urban Green Space a Carbon Sink or Source? - A Case Study of China Based on LCA Method

Vegetation sequester and store carbon in their tissue, at the same time, vegetation plantation and maintenance practice release carbon back to the atmosphere based on energy-resource consumption and labors input. However, existing studies have not yet provided an exhaustive calculation of carbon balance for China from vegetation type. Thus, accounting and understanding carbon balance of urban green space (UGS) are of great important especially in China which is facing rapid industrialization and urbanization as the biggest developing country in the world. This study seeks to determine whether UGS is a carbon sink or a carbon source. Using field surveys, interviews and model simulation over a 50-year time period, carbon sequestration and emissions of four green space in China were evaluated to determine how factors influence the carbon balance. Management practices to maximize the net carbon sequestration are discussed. The main results are as follows: 1) trees and shrubs were carbon sinks with 11,972.08 and 5758.07 MgCO2e ha−1 and the lawns were carbon sources with 149.15 MgCO2e ha−1 in life cycle. 2) Populus tomentosa, Fraxinus chinensis and Lonicera maackii had the most net carbon sequestration. 3) the main contributions of carbon emissions in parks were irrigation and pesticide use.