210 SEEDING AND PLANTING 



Loose and dry soils permit of a comparatively deep covering 

 over the seed while heavy and wet soils require a shallow cover- 

 ing. On sites exposed to the full action of the sun the covering 

 should be thicker than on shady sites. On average sites the 

 depth of covering should not exceed from 1 to 3 times the diam- 

 eter of the seed. The following table shows the average depth 

 of covering for a number of species : 



Inches Inches 



2. METHODS OF DIRECT SEEDING 



The various methods of direct seeding may be classed under 

 the following heads: 



a. Full seeding. 



b. Partial seeding. 



In full seeding the seed is distributed more or less evenly over 

 the entire area to be stocked. In partial seeding only definite 

 portions of the area are seeded. In the latter case the cost of 

 regeneration on sites that require soil preparation is usually less, 

 due to the smaller quantity of seed required and the necessity for 

 cultivating only a portion of the total area. 



3. Full Seeding 



Contrary to general opinion, full seeding when properly done is 

 usually expensive, often more so than partial seeding or even 

 planting. Only in exceptional instances where the large amount 

 of seed required can be obtained at a relatively low cost and where 

 it can be. sown without preliminary treatment of the site is it pos- 

 sible to attain successful regeneration at a low cost by full seeding. 

 At the present prices of forest tree seed in the United States the 

 cost of the seed alone prohibits full seeding with many economic 

 species. Even with relatively inexpensive seed this manner of 

 regeneration must usually be confined to recently cleared and 

 burned areas that require little or no cultivation. Failures have 

 resulted from most attempts at full seeding in this country be- 

 cause we have used far too little seed per unit of area and have not 

 given enough attention to the preparation and protection of the site. 



