340 A NATIONAL PLAN FOE AMERICAN FORESTRY 



inclusion might be justified by the critical importance of water in 

 this zone of dense population. The low percentage of forest land, 

 however, makes it difficult to justify such a classification in advance 

 of evidence, drawn from local experimentation, on both the absolute 

 influence and the relative influence of the forest as compared with 

 very carefully managed agricultural crops. 



Roughly, one third, or 14,000,000 acres, of the forest area of the 

 region is included in each of the zones in which the forest is believed to 

 exert a major, a moderate, and a slight influence on run-off and 

 stream flow. 



There is every reason to believe that whatever measures of protec- 

 tion and management promote other values of the northeastern 

 forests will also increase their value as regulators of stream flow and 

 preventives of erosion. They should be adopted forthwith. These 

 measures, as described in other sections of this report, include ^(1) 

 intensified fire protection wherever in the region recognized objectives 

 of fire control have not yet been reached, (2) halting devastation of 

 any land, public or private, and (3) improving watershed conditions 

 by planting where necessary. Present knowledge leads to the belief 

 that about a half million acres of major influence land in the north- 

 eastern drainages require planting for watershed purposes alone. 

 If adequate fire protection and planting in certain localities' such as 

 the anthracite coal region of Pennsylvania' involve expenditures 

 so far beyond those which the private owner can afford to make that 

 the public is forced to assume the greater part of the burden, outright 

 public acquisition appears inescapable. Intensified fire protection 

 and halting of devastation will go a long way toward protecting the 

 existing forest cover against degeneration. The public need for water 

 and for safety from floods and erosion suggests that some 7.8 millions 

 acres should be publicly owned and managed. Approximately 

 900,000 acres of this total is abandoned farm land. 



A third major need in the solution of the stream-flow and watershed 

 problems of the region is research. There is need for exact experi- 

 mental evidence on the relative water use of the different species of 

 native vegetation under the climatic conditions peculiar to the 

 region and under different geological conditions. Differences in 

 interception of rainfall by the crowns, in rate of percolation and 

 absorption through the leaf litter and in rate of snow melt beneath 

 tree crowns, must be determined for various types and species. 

 Control of drifting sands by vegetation should be studied. The effect 

 upon run-off and stream flow of a mixed conifer and hardwood forest 

 as compared with a pure forest of either conifers or hardwoods; the 

 effect upon wind movement and evaporation of an all-aged forest as 

 compared with an even-aged forest these and similar problems arising 

 out of intensive management may be solved only by experimentation. 

 Research should be conducted first and on the most comprehensive 

 scale in the zone of intensive use of water for domestic and industrial 

 purposes. 



SOUTH ATLANTIC DRAINAGES 



The South Atlantic drainages, as the term is here used, include the 

 Potomac River and all of the streams draining into the Atlantic Ocean 

 southward from it, to but not including the Savannah River (fig. 4). 

 Because of the difficulty of segregating for different portions of a 



