REFORESTATION ON THE NATIONAL FORESTS. 49 



STOCK. 



If large areas are to be reforested, stock should be excluded, and, 

 if possible, sheep should be excluded from any plantation as they do 

 more damage to coniferous plants than any other animal, goats 

 excepted. As a rule, cattle do not damage plantations much, pro- 

 vided the ground is not plowed, the area is not close to salting and 

 watering places, and the stock is not permitted to concentrate too 

 much in particular localities. Fencing against live stock is seldom 

 advisable, and where exclusion is necessary it should be based upon 

 natural boundaries. 



The pine-tip moth has damaged plantations in Nebraska, and the 

 white grub of the June beetle cuts off the roots of young planted stock 

 in the southwest. No practicable method of combating these insects 

 over large areas has been devised. 



Grasshoppers have destroyed whole plantations on the old Kansas 

 National Forest, attacking both hardwoods and conifers. Methods of 

 control of these insects through burning, poisoning, and trapping 

 have been worked out in California, 1 but it seems that certain meth- 

 ods are effective only with certain species, and control measures must 

 accordingly be worked out for each region. 



DISEASES. 



Diseases in plantations on the National Forests have not been at 

 all serious. Were dangerous diseases to appear it might be imprac- 

 tical as well as impossible to stamp them out. It is well, therefore, 

 to warn against the planting in one general region of nursery stock 

 grown in another unless there is absolute certainty that it is not 

 affected by diseases which may prove harmful to the native timber 

 where the stock is to be planted. White pine grown in regions where 

 the white-pine blister rust is prevalent should not be planted in the 

 western white pine and sugar pine regions; and western yellow-pine 

 nursery stock produced in a region where mistletoe is present should 

 not be shipped, for instance, to the Black Hills where this disease 

 does not occur. Great economic losses are possible through the ship- 

 ment of diseased or insect-infested stock. 



Young planted stock is often damaged by rodents, and tree seed is 

 very attractive to them. In many cases it is their natural food, and 



1 Cal. Agri. Exp. Sta. Bui. 170, " Studies in Grasshopper Control." 



