OOS 16-7
Warming methods for ecosystem plots and scaling to tree-size
Global warming is likely to cause changes in ecosystems world-wide. In order to study the likely effects on the ecosystems, including implications for Earth’s global carbon budget and feedback/feedforward effects on the degree of global warming, scientists need to conduct experiments that simulate future environmental conditions as closely as possible. Methods currently in use include soil warming cables and tubes, nighttime curtains, transport of soil monoliths up and down elevation gradients, passive and active open-top chambers, constant-flux infrared heaters, and constant-temperature-difference infrared heaters. Pros and Cons of each are presented. Although not perfect, the constant-temperature-difference infrared heater method can produce increases in vegetation temperature day and night in open-field plots that most closely represent conditions expected in the future.
Results/Conclusions
One of the larger uncertainties in Earth’s global carbon budget is what will happen to tropical forests with global warming. As mentioned above, infrared heating can produce conditions most representative of future global warming. However, to date no one has conducted an experiment at a tree scale. Experiments with vegetation on the scale of one meter tall have shown the method works well with 3-m-diameter plots. This suggests that 10-m-tall trees will require plots on the order of 30-m diameter. Theory is presented that shows by nesting hexagonal arrays in a honeycomb pattern, it should be possible to achieve excellent uniformity of the infrared radiation over such large plots. Additional theory is presented about how much electrical energy will be required to achieve desired degrees of warming and associated costs.