DISEASE CONTROL AND FOREST MANAGEMENT 977 



ceptible to the disease, for at least one rotation, to insure the complete 

 eradication of it from the area, and to take other measures for control 

 demanded by the special exigencies of the case. 



It also frequently happens that a pathogene causing an epiphytotic 

 disease is not selective of any single age class or group of age classes. 

 In such a case, as soon as the disease appears the emphasis in regulation 

 must be taken away from the object of sustained yield and laid upon 

 sanitation, if possible. If sanitation is impracticable because of the 

 extensive occurrence of the disease at the time of its discovery or of 

 the initiation of a systematic management, the regulation must concern 

 itself primarily with damage cuttings, and silviculture should provide 

 for the substitution of resistant or immune species. An example of 

 such a case is given in the working plan for the Luther Forest Preserve, 

 Saratoga County, New York (Cornell University, Department of For- 

 estry, 1916), from which the following is quoted: 



"(3) Marking rules : 



"Take out actually diseased cheetnut at present, because the removal 

 of all chestnut would leave too open stands. Also there is a chance 

 that the blight will be checked and chestnut may once more take its 

 place in the forest." 



In addition, the general planting plan in the working plan provides 

 for reforestation with white pine {Pinus strobus) and red pine (Pinus 

 resinosa) in mixture. 



The object here is for cutting to keep pace with the advance of the 

 disease and for the planting to replace the present stand containing this 

 susceptible species with species of an entirely different character. 



In conclusion, the combining of disease control with intensive forest 

 management calls for an adjustment of the rotation, cutting cycle, and 

 marking rules in such ways as, in the case of enphytotics, to control the 

 disease by measures of sanitation, and by limiting the felling age so that 

 loss is minimized ; and in the case of epiphytotics, to make "sanitation" 

 cuttings, or damage cuttings, or both, and employ certain silvicultural 

 measures, such as the substitution of other species which are more re- 

 sistant or immune. 



UTERATURE CITED 



Department of Forestry: Working Plan for the Luther Forest Preserve. 

 N. Y. State College of Agriculture at Cornell University, Ithaca, N. Y., 1916. 

 (Unpublished MSS.) 



Meinecke, E. P. : Forest Pathology in Forest Regulation. U. S. D. A. Bulletin 

 275 : 1-63, 1915- 



Recknagel, A. B. : The Theory and Practice of Working Plans. 2d edition. 

 Pis. 1-6, figs. 1-2, I-XIV, 1-265, 1917- 



