Design and performance of an ecosystem-scale forest soil warming experiment with infrared heater arrays

<p><span>How forest ecosystems respond to climate warming will determine forest trajectories over the next 100 years. However, the potential effects of elevated temperature on forests remain unclear, </span><span>primarily because of the absence of long-term and large-size field warming experiments in forests, especially in Asia.</span></p> <p><span>Here, we present the design and performance of an ecosystem-scale warming experiment</span><span> using an infrared (IR) heater array in a 60-year-old temperate mixed forest at Qingyuan Forest CERN in northeastern China.</span></p> <p><span>In paired </span><span>108 m² plots (n = 3),</span><span> the surface soils were constantly elevated 2 degrees</span><span> above control plots with a feedback control system over four years (2018-2021). Subsoils down to 60 cm depth were warmed 1.2-2 degrees</span><span>. Soil warming did not affect soil moisture either in surface soils or subsoils. Turn-off time due to weather extremes (heavy rains, snow) and power outages only accounted for 2.5% of the total warming period.</span></p> <p><span>In conclusion, we provide a proof-of-principle setup that allows long-term analysis of forest response to warming temperatures in large-size field plots. Importantly, our warming experiment demonstrated the feasibility of IR heater arrays for soil warming in tall-statured forest ecosystems.</span></p>