Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario, Canada.
Daniels Faculty of Architecture, Landscape, and Design, University of Toronto, 1 Spadina Cresent, Toronto, Ontario, Canada.
J Environ Manage. 2024 Jun;360:121047. doi: 10.1016/j.jenvman.2024.121047. Epub 2024 May 17.
Green roofs are well studied for the environmental, social, and economic services these provide. As a result, green roofs are widespread and within the common vernacular of city residents. Green roof bylaws and construction standards are present in many cities in North America, rooting the presence of this green infrastructure within urban landscapes. Although examples of green roofs constructed decades ago exist, rarely are green roofs monitored over such long periods, and in ways that allow for experimentation, analysis, and conclusions about performance or function. In this study we present findings on plant cover and biomass from a green roof testing facility in Toronto, Canada that was monitored for over a decade. We examine the contributions of growing media, planting, and irrigation in the first seven years (2011-2021) of the eleven-year monitoring period. We found that during this maintenance phase period (2011-2017), plant cover and biomass was highest in modules planted with Sedum, included organic media, and were irrigated, whereas non-irrigated modules planted with forbs and grasses had the poorest performance regardless of media type. Following the stoppage of irrigation, and the post maintenance phase (2017-2021), modules initially planted with Sedum continued to sustain cover and biomass whereas planted forbs and grasses mostly disappeared, and these treatments were overtaken by Sedum. Our findings demonstrate that with irrigation, plantings of forbs and grasses can sustain plant cover and biomass. However, Sedum buffers against major changes to environmental conditions or abrupt changes to maintenance, adding insurance against failure of extensive green roofs.
绿色屋顶因其提供的环境、社会和经济效益而得到广泛研究。因此，绿色屋顶在北美许多城市都很普遍，也是城市居民常用的说法。绿色屋顶法规和建筑标准存在于许多北美城市，使这种绿色基础设施在城市景观中扎根。尽管几十年前建造的绿色屋顶的例子存在，但很少有绿色屋顶能够在如此长的时间内进行监测，也很少有绿色屋顶能够以允许进行实验、分析和得出关于性能或功能的结论的方式进行监测。在这项研究中，我们展示了来自加拿大多伦多的一个绿色屋顶测试设施的植物覆盖和生物量的研究结果，该设施已经监测了十多年。我们检查了在十一年监测期间的前七年（2011-2021 年）中，生长介质、种植和灌溉的贡献。我们发现，在维护阶段（2011-2017 年），种植景天属植物、含有有机介质并进行灌溉的模块的植物覆盖率和生物量最高，而不进行灌溉、种植杂类草和禾本科草的模块的性能最差，而不管介质类型如何。在停止灌溉和维护后阶段（2017-2021 年），最初种植景天属植物的模块继续保持覆盖和生物量，而种植的杂类草和禾本科草大多消失，这些处理被景天属植物所取代。我们的研究结果表明，在灌溉的情况下，杂类草和禾本科草的种植可以维持植物的覆盖率和生物量。然而，景天属植物可以缓冲环境条件的重大变化或维护的突然变化，为大面积绿色屋顶的失效增加了保险。
