in water yields reflects the timing of the regional land use 
changes. 
Further shifts from timberland to urban use, and to crop 
and pasture use, would result in additional increases in water 
runoff. However, the South is experiencing rapid declines 
in groundwater levels due to withdrawals for irrigation and 
domestic water supply. Such shifts would probably result 
in less groundwater recharge. 
Resource, Economic, and Environmental Implica- 
tions of Other Futures 
The preceding discussion has been concerned with one future 
based on the complex set of assumptions about determinants 
of timber demands and supplies described in chapter 3. 
Future changes in these determinants may be quite different 
from what has been assumed. They can also be changed by 
design—by legislation or administrative action to alter the 
policies and programs that affect either demand or supply. 
It is obviously impractical to deal in any comprehensive way 
with all the possible uncertainties and policy and program 
changes. The executive group guiding this study devoted 
substantial time to discussing the kinds of futures that 
should be analyzed. The group was particularly concerned 
about legislation currently being considered, farm and 
forestry programs under discussion at Federal and State 
levels, and some of the major uncertainties associated 
with the demand and supply projections. After extended 
discussion, the executive group selected the following 
futures for analysis: 
1. The future as described by the basic assumptions and 
other specified and implied assumptions underlying the 
projections in chapter 3. 
2. Improved processing efficiency. The future as described 
by the assumptions in chapter 3, modified by increasing 
softwood lumber and plywood yields by 25 percent instead 
of the 10-percent increase assumed in the base projection. 
The increase in yields are staged in the progression 9, 7, 5, 
3, and | percent per decade. 
3. High exports of timber products. The future as 
described by the assumptions in chapter 3, modified by 
increasing the projected exports of lumber, plywood, and 
pulpwood (including pulpwood and the pulpwood equivalent 
of pulp, paper, and board) by 20 percent in 1990, 40 
percent in 2000, 60 percent in 2010, 80 percent in 2020, and 
100 percent in 2030. 
4. High imports of timber products. The future as 
described by the assumptions in chapter 3, modified by 
increasing the projected imports of plywood, pulpwood 
(including pulpwood and the pulpwood equivalent of pulp, 
paper, and board), and hardwood lumber and logs by 20 
percent in 1990, 40 percent in 2000, 60 percent in 2010, 80 
percent in 2020, and 100 percent in 2030. 
5. Reduced timberland area. The future as described by 
the assumptions in chapter 3, modified by reducing the 
projected area in timberland in the South by 2 million acres 
in 1990, 5 million acres in 2000, and 11 million acres in 
2030. 
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