Zhao Chang, Sander Heather A
Department of Geographical and Sustainability Sciences, University of Iowa, Iowa City, Iowa, United States of America.
PLoS One. 2015 Aug 28;10(8):e0136392. doi: 10.1371/journal.pone.0136392. eCollection 2015.
Studies that assess the distribution of benefits provided by ecosystem services across urban areas are increasingly common. Nevertheless, current knowledge of both the supply and demand sides of ecosystem services remains limited, leaving a gap in our understanding of balance between ecosystem service supply and demand that restricts our ability to assess and manage these services. The present study seeks to fill this gap by developing and applying an integrated approach to quantifying the supply and demand of a key ecosystem service, carbon storage and sequestration, at the local level. This approach follows three basic steps: (1) quantifying and mapping service supply based upon Light Detection and Ranging (LiDAR) processing and allometric models, (2) quantifying and mapping demand for carbon sequestration using an indicator based on local anthropogenic CO2 emissions, and (3) mapping a supply-to-demand ratio. We illustrate this approach using a portion of the Twin Cities Metropolitan Area of Minnesota, USA. Our results indicate that 1735.69 million kg carbon are stored by urban trees in our study area. Annually, 33.43 million kg carbon are sequestered by trees, whereas 3087.60 million kg carbon are emitted by human sources. Thus, carbon sequestration service provided by urban trees in the study location play a minor role in combating climate change, offsetting approximately 1% of local anthropogenic carbon emissions per year, although avoided emissions via storage in trees are substantial. Our supply-to-demand ratio map provides insight into the balance between carbon sequestration supply in urban trees and demand for such sequestration at the local level, pinpointing critical locations where higher levels of supply and demand exist. Such a ratio map could help planners and policy makers to assess and manage the supply of and demand for carbon sequestration.
评估生态系统服务在城市地区所提供效益分布的研究日益普遍。然而，目前对于生态系统服务供需双方的了解仍然有限，这使得我们在理解生态系统服务供需平衡方面存在差距，限制了我们评估和管理这些服务的能力。本研究旨在通过开发和应用一种综合方法来填补这一差距，该方法用于在地方层面量化一种关键生态系统服务——碳储存与封存——的供需情况。此方法遵循三个基本步骤：（1）基于光探测与测距（LiDAR）处理和异速生长模型量化并绘制服务供给情况；（2）使用基于当地人为二氧化碳排放的指标量化并绘制碳封存需求；（3）绘制供需比地图。我们以美国明尼苏达州双城都会区的一部分为例来说明这种方法。我们的结果表明，研究区域内的城市树木储存了1.73569亿千克碳。树木每年封存3343万千克碳，而人类活动排放30.876亿千克碳。因此，研究地点城市树木提供的碳封存服务在应对气候变化方面作用较小，每年仅抵消约1%的当地人为碳排放，尽管树木储存所避免的排放相当可观。我们的供需比地图有助于了解城市树木碳封存供给与地方层面此类封存需求之间的平衡，确定供需水平较高的关键地点。这样的比例地图可以帮助规划者和政策制定者评估和管理碳封存的供需情况。
