Growth Index (1977 = 100) 
120 
100 
80 
60 
20 
Figure 8—Research is needed to determine the 
potential effects of global climate change on the 
productivity of forest and range land. Apparatus 
such as this open-top chamber are used in 
climate research. 
opportunities may lead to increases in 
the quantity and/or quality of the use of 
the resources. 
Trends in Areas 
In recent years, the area of forest and 
range land has been declining as these 
lands have been converted to other 
uses. The water area has been 
increasing due to the construction of 
ponds and lakes (reservoirs). The total 
output of products from forest and 
