82 OUR NATIONAL FORESTS 



is mountainous or level, and many other factors. 

 In this way Uncle Sam plants his denuded areas 

 in the Forests, so that they will be producing timber 

 for future generations instead of useless brush or 

 tree weeds. The great variety of climatic and 

 topographic conditions included in the National 

 Forest area makes the problem of tree planting in- 

 finitely complex. Nursery stock must be raised in 

 each region having similar climatic conditions, and 

 in each of these regions different methods of plant- 

 ing must be used, depending upon local conditions. 

 The semi-arid mesas of Arizona and New Mexico 

 present different planting problems from the humid 

 forest regions of Oregon and Washington; the 

 methods used in the sandhills of Nebraska and the 

 sand plains of Michigan cannot be applied in full 

 on the high mountain slopes of Colorado; nor are 

 the planting problems in the vast chaparral areas of 

 northern California anything like those encountered 

 in the mountains of Idaho, or in the prairie States of 

 the Middle West, or in the Black Hills. Then, 

 again, the reforestation problems of the chaparral 

 fields of southern California are more perplexing 

 than any I have mentioned above. 



