Data from: Open-top chambers for temperature manipulation in taller-stature plant communities

Open-top chambers simulate global warming by passively increasing air temperatures in field experiments. They are commonly used in low-stature alpine and arctic ecosystems, but rarely in taller-stature plant communities because of their limited height. We present a modified International Tundra Experiment (ITEX) chamber design for year-round outdoor use in warming taller-stature plant communities up to 1.5m tall. We report a full year of results for the chambers’ effects on air and soil temperature, relative humidity, and soil moisture in a northern hardwood forest clearing and a southern early successional grassland site located in Michigan, USA. Detailed construction plans are also provided. The chambers elevated daytime air temperatures at 1m height by 1.8ºC above ambient levels, on average over an entire year, at both the northern and southern site. The chambers did not affect relative humidity at either site. The chambers did not alter average soil temperature or moisture at the northern site and reduced soil temperatures and soil moisture at the southern site. The chambers increased variability in soil freeze/thaw cycles at both sites. The chambers achieved predicted levels of warming for mid-century (2046-2065) scenarios consistent with the majority of Representative Concentration Pathways (RCPs) in the International Panel on Climate Change 5th Assessment Report, with minimal experimental artifact. This design is a valuable tool for examining the effects of in situ warming on understudied taller-stature plant communities and creates the opportunity to expand future comparisons across a diversity of systems.开顶箱（Open-top chambers）通过被动提升野外实验中的空气温度来模拟全球变暖。该类装置常被应用于低矮型高山与北极生态系统，但由于高度限制，极少用于高大植物群落研究。 本研究提出一种改良版国际苔原实验（International Tundra Experiment, ITEX）箱式装置设计，可全年户外应用于高度可达1.5米的高大植物群落的增温实验。我们报告了该装置在美国密歇根州一处北部落叶阔叶林空地与一处南部早期演替草地样地中，为期一整年的空气温度、土壤温度、相对湿度与土壤湿度监测结果，同时附带详细的施工方案。 在南北两个样地中，该装置在全年平均水平下，可使1米高度处的日间空气温度较环境水平提升1.8℃。该装置对两处样地的相对湿度均无显著影响。在北部样地中，装置未改变土壤温度与土壤湿度的平均值；而在南部样地中，装置则降低了土壤温度与土壤湿度。该装置提升了两处样地的土壤冻融循环变异性。 该装置实现了与政府间气候变化专门委员会（Intergovernmental Panel on Climate Change, IPCC）第五次评估报告中多数代表性浓度路径（Representative Concentration Pathways, RCPs）所匹配的本世纪中叶（2046-2065年）增温预测水平，且实验人为干扰极小。该设计为探究原位增温对研究不足的高大植物群落的影响提供了有效工具，并为未来开展多系统间的对比研究创造了条件。