Horn Josh, Escobedo Francisco J, Hinkle Ross, Hostetler Mark, Timilsina Nilesh
School of Natural Resources and the Environment, University of Florida, 361 Newins-Zeigler, Gainesville, FL, 32611, USA.
Environ Manage. 2015 Feb;55(2):431-42. doi: 10.1007/s00267-014-0400-1. Epub 2014 Nov 13.
There are few field-based, empirical studies quantifying the effect of invasive trees and palms and maintenance-related carbon emissions on changes in urban forest carbon stocks. We estimated carbon (C) stock changes and tree maintenance-related C emissions in a subtropical urban forest by re-measuring a subsample of residential permanent plots during 2009 and 2011, using regional allometric biomass equations, and surveying residential homeowners near Orlando, FL, USA. The effect of native, non-native, invasive tree species and palms on C stocks and sequestration was also quantified. Findings show 17.8 tC/ha in stocks and 1.2 tC/ha/year of net sequestration. The most important species both by frequency of C stocks and sequestration were Quercus laurifolia Michx. and Quercus virginiana Mill., accounting for 20% of all the trees measured; 60% of carbon stocks and over 75% of net C sequestration. Palms contributed to less than 1% of the total C stocks. Natives comprised two-thirds of the tree population and sequestered 90% of all C, while invasive trees and palms accounted for 5 % of net C sequestration. Overall, invasive and exotic trees had a limited contribution to total C stocks and sequestration. Annual tree-related maintenance C emissions were 0.1% of total gross C sequestration. Plot-level tree, palm, and litter cover were correlated to C stocks and net sequestration. Findings can be used to complement existing urban forest C offset accounting and monitoring protocols and to better understand the role of invasive woody plants on urban ecosystem service provision.
很少有基于实地的实证研究来量化入侵树木和棕榈以及与维护相关的碳排放对城市森林碳储量变化的影响。我们通过在2009年至2011年期间重新测量住宅永久样地的子样本、使用区域异速生物量方程以及对美国佛罗里达州奥兰多附近的住宅业主进行调查，估算了亚热带城市森林中的碳（C）储量变化和与树木维护相关的碳排放量。还量化了本地、非本地、入侵树种和棕榈对碳储量和碳固存的影响。研究结果表明，碳储量为17.8吨碳/公顷，净碳固存率为1.2吨碳/公顷/年。按碳储量和碳固存频率计算，最重要的物种是月桂叶栎（Quercus laurifolia Michx.）和弗吉尼亚栎（Quercus virginiana Mill.），占所有测量树木的20%；占碳储量的60%和净碳固存的75%以上。棕榈对总碳储量的贡献不到1%。本地树种占树木总数的三分之二，固存了所有碳的90%，而入侵树木和棕榈占净碳固存的5%。总体而言，入侵和外来树木对总碳储量和碳固存的贡献有限。与树木相关的年度维护碳排放量占总碳固存总量的0.1%。样地层面的树木、棕榈和凋落物覆盖与碳储量和净碳固存相关。研究结果可用于补充现有的城市森林碳抵消核算和监测协议，并更好地理解入侵木本植物在城市生态系统服务提供中的作用。
