TREE-PLANTING ON PRAIRIES. 49 



successful plantings have been made on this plan, but 

 when planted so closely together, the branches grow into 

 the rows after a few years and cultivation must be discon- 

 tinued. In this country we have so much very bright 

 sunshiny weather that grass can grow under foliage that 

 would kill it out in a more humid climate, and we find that 

 trees planted four feet apart each way seldom afford suffi- 

 cient shade to kill the grass under them for many years. 

 This is especially true of such trees as the Cottonwood, , 

 Lombardy Poplar, and White Elm when planted alone, as 

 they have open foliage that does not furnish a dense shade. 

 Among tree-planters who have had a large experience in 

 prairie-planting, there has been a tendency of late years to 

 plant two feet apart in rows eight feet apart, and some of 

 our most successful planters prefer even more room than 

 this between the rows. When plantings are made 2x8 

 feet, the same number of trees are required for an acre as 

 when planted 4x4 feet, but the former distance has the 

 advantage over the latter in that the space between the 

 rows can be cultivated for perhaps ten years or more, by 

 which time most trees will have formed a dense shade and 

 be able to take care of themselves. Where a much greater 

 distance than eight feet is allowed between the rows, we 

 generally fail to get forest conditions for many years, and to 

 that extent fall short of an important requisite in prairie- 

 planting. The distances given here might need to be modi- 

 fied to suit different varieties and local climatic conditions. 

 Clear Plantings. Most of the plantings on our prairies 

 consist wholly of one kind. In some cases best results 

 are thus obtained, but they are seldom as satisfactory as 

 plantings made up of several different kinds. One of the 

 greatest drawbacks to plantings made up entirely of one 

 kind is that the fact that drought, insects, or fungous dis- 

 ease may destroy the whole planting at one time, while 

 in a judiciously mixed planting this could hardly occur. 



