GENERAL CONSIDERATIONS 87 



10. MIXED REGENERATION 



In the formation of forest crops it is often advantageous to 

 combine natural with artificial regeneration. A naturally regen- 

 erated stand is sometimes so open in places that it must be 

 completed either by seeding or by planting. Conditions in the 

 different parts of most forests are variable. By shaping the re- 

 generation to fit the conditions, greater success and usually a 

 reduction in cost are assured. The forms of mixed regeneration 

 are as follows : 



a. The combination of natural regeneration from seed and arti- 

 ficial regeneration by seeding. 



6. The combination of natural regeneration from seed and 

 artificial regeneration by planting. 



c. The combination of regeneration from stool shoots or suckers 

 and artificial regeneration by planting. 



d. The combination of regeneration from stool shoots or suckers 

 and artificial regeneration by seeding. 



e. The combination of regeneration from stool shoots and nat- 

 ural seeding and artificial regeneration by seeding or planting. 



Failed places from natural regeneration are sometimes filled by 

 direct seeding. This method, however, is permissible only under 

 exceptional conditions. The seeding should be done as soon as 

 the failures are apparent, or soil deterioration and competing 

 vegetation will render it more and more difficult. Where beech, 

 maple or other soil-improving hardwoods are grown with pine or 

 other conifers, the artificial regeneration of the conifers is often 

 combined with the natural regeneration of the hardwoods. In 

 felling stands of spruce and pine that contain a small admixture 

 of beech, it is a common practice in Europe to leave from 4 to 12 

 beech trees per acre. Later the area is planted or seeded with 

 pine or spruce. The overstanding beech by natural seeding pro- 

 vide from 5 to 20 per cent of the new stand (Fig. 8). 



In most instances where natural regeneration is incomplete, it 

 can be completed most economically and satisfactorily by planting. 

 The failures from natural seeding usually occur on the poorest 

 and driest sites where the results of direct seeding are extremely 

 uncertain. 



In mixed woods the most desirable species sometimes fail to 

 regenerate by natural seeding, making it necessary to bring them 

 hi by artificial means. For one cause or another, the old type of 



