Recall that net primary productivity (NPP) is the rate at which producers can make the chemical energy that is stored in their tissues and that is potentially available to other organisms (consumers)...

Recall that net primary productivity (NPP) is the rate at which producers can make the chemical energy that is stored in their tissues and that is potentially available to other organisms (consumers) in an ecosystem. In Figure 3.18, it is expressed as units of energy (kilocalories, or kcal) produced in a given area (square meters, or m2) per year. Look again at Figure 3.18 and consider the differences in NPP among various ecosystems. Then answer the following questions:

Early in the 20th century, large areas of temperate forestland in the United States were cleared to make way for agricultural land. For each unit of this forest area that was cleared and replaced by farmland, by about how much was NPP reduced?