710 A NATIONAL PLAN FOR AMERICAN -FORESTRY 



simplification of protection methods based on principles already dis- 

 covered in the laboratory and in the direction of further fundamental 

 research without which entirely satisfactory field methods can never 

 be developed. Both the present information and that later developed 

 need to be made more readily available to the smaller wood producers 

 and wood users by service and demonstration work. 



OUTLOOK 



Among the factors tending to increase damage by fungi to forest 

 products are the increasing volume of small-mill lumbering, use of 

 less durable species and of a higher proportion of sapwood, and the 

 architectural trend toward low foundations. However, practicable 

 improvements in seasoning and preservative processes and in build- 

 ing practices, and the increased use of treated wood or of wood sub- 

 stitutes in situations of high-decay hazard, should more than count- 

 eract the unfavorable factors and result in some net decrease in decay 

 damage, as well as in decided decrease in the losses from sap stain. 

 The possibilities in the way of preventing fungous damage are much 

 greater in forest products than in forest trees. The products losses 

 have already been reduced far below those that would occur without 

 active control procedure. It would be technically possible to develop 

 practices that would prevent practically all loss; it is doubtful, how- 

 ever, if the reduction in fungous damage in the next 20 years will be 

 any more rapid than the reduction that is expected in forest growth. 

 Increased protection against fungous attack will take place concur- 

 rently with advance in three processes : Kesearch aimed at the cheap- 

 ening and simplification of protective methods, education of wood 

 users as to improved practice, and increase in lumber prices which 

 will increase the number of types of use in which protection is cheaper 

 than replacement. 



Further consideration of the pathology and protection of forest 

 products will be found in the section entitled "Enlarging the Con- 

 sumption of Forest Products." 



FOREST DETERIORATION BY INTRODUCED DISEASES 



In the foregoing nothing has been said of the dangers of serious and 

 widespread epidemics. Native fungi, or fungi that have been intro- 

 duced in the remote past and to which our forests have already 

 become adjusted are not likely to cause catastrophic epidemics in 

 native tree species or threaten the extermination of any commercial 

 forest tree. The introduced disease, on the other hand, is a potential 

 danger to the commercial existence of every one of our commercially 

 important timber species. 



The history of agriculture and horticulture in this country prior to 

 the passage of the Plant Quarantine Act of 1912 and to the issue of 

 the general nursery stock importation restrictions in 1919 was a 

 procession of invasions by both plant diseases and insect pests from 

 abroad. Wheat, potato, cotton, corn, asparagus, and peach are 

 among the important crop plants that have suffered from foreign 

 attack at one time or another in our history. Most of the attacks 

 have been met by the quick substitution of resistant varieties, by a 

 shift of the center of cultivation from one part of the country to 



