Environmental Science 15th Edition by Scott Spoolman,Tyler Miller

تمرين 18

Consider the graph to the right that compares the losses of calcium from the experimental and control sites in the Hubbard Brook Experimental Forest ( Core Case Study ). Note that this figure is very similar to Figure 2.5, which compares loss of nitrates from the two sites. After studying this graph, answer these questions.

In what year were the calcium losses from the two sites closest together? In the span of time between 1963 and 1972, did they ever get that close again?