Living in the Environment 18th Edition by Tyler Miller,Scott Spoolman

تمرين 16

Consider the graph on the right that shows loss of calcium from the experimental cutover site of the Hubbard Brook Experimental Forest ( Core Case Study ) compared with that of the control site. 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 the questions below.

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