670 A NATIONAL PLAN FOR AMERICAN FORESTRY 



forest pathology, although essential parts of this subject, are not 

 discussed because they are administered in other bureaus of the 

 Department of Agriculture. 



NATURAL REFORESTATION 



Although planting has the greatest popular appeal, it is on natural 

 processes of regeneration that the forester must very largely depend 

 for the perpetuation of the forest. Accordingly the latter has re- 

 ceived by far the greater emphasis in research. For a rather large 

 percentage of the most important forest types in the United States, 

 research findings to date show in a fairly satisfactory way how natural 

 reproduction can be obtained or how to reestablish the forest by con- 

 trolling the method of cutting the mature forest. Or conversely, 

 they show for most of our more important forest types how to pre- 

 vent the forest devastation which has been such a widespread evil in 

 the United States; and also how to prevent forest deterioration, which 

 has been a less spectacular but probably an even greater evil. Some 

 of these findings, as for example in the ponderosa pine, Douglas fir, 

 and eastern spruce forests, involve significant adaptations of the 

 standard European silvicujtural methods to the requirements of 

 American species and American conditions. 



The work done in this and other connections has in the aggregate 

 accumulated a rather impressive knowledge of the taxonomy and 

 distribution of our forest trees, of the life histories and requirements 

 of many of the most important species, and of the ecological relation- 

 ships of many important single species and forest types. The ground 

 to be covered is far greater than that which has been covered, but 

 much of our silviculture of natural forest regeneration is no longer 

 entirely blind and without fundamental foundation. 



Looking at our needs in a broad national way, a very large field of 

 work in the reestablishment of forests or in obtaining natural repro- 

 duction still remains. Much of the information so far obtained is 

 empirical and too little progress has been made in breaking the prob- 

 lem down into its constituent factors, which is a necessary preliminary 

 to an intensive attack. Far too little, to illustrate, has been accom- 

 plished in breaking down problems of light, soil, moisture, competi- 

 tion, physiological responses to environment, etc., as a basis for the 

 evaluation of these factors through intensive research. 



Much less progress can be shown on the problem of carrying estab- 

 lished forest lands through to maturity, although a good beginning 

 has been made. Large numbers of sample plots have been established, 

 but nearly all are still too recent to render their fullest value. Thin- 

 ning plots and those representing other cultural operations are fewer 

 in number. In general, the work along this line is in a preliminary 

 empirical stage. 



As in the initial problem of establishing the young forest, practi- 

 cally everything is ahead in breaking down into its constituent factors 

 the problem of carrying established stands to maturity, as a prelimi- 

 nary to intensive attack. Large additional quantities of both 

 empirical and intensive work will be necessary before we shall be in 

 a position to say with assurance what are the best species and mix- 

 tures for various conolitions of soil, etc.; how we shall manage our 

 stands to insure quantity or quality production or the right combina- 



