374 



GENERAL BOTANY 



Maintaining the supply. Maintaining the supply of spruce for 

 wood-pulp production and other commercial purposes is closely 

 connected with the amount and nature of the seed production, 

 since spruce forests are recreated or regenerated largely by 

 means of seeds. In the case of hardwood trees, to be discussed 

 below, vegetative reproduction by means of sprouts from the 

 stumps is often used hi the regeneration of a forest destroyed 



by cutting or by other 

 agencies. In the case of 

 most of the coniferous 

 trees the sprout method 

 is not possible, since, with 

 few exceptions, these trees 

 do not reproduce vege- 

 tatively in this manner. 

 The production of new 

 stands of spruce by means 

 of seeds may be either 

 by the natural method, 

 where the growth of seed- 

 lings occurs in a spruce or 

 a mixed forest (Fig. 229), 

 or by artificial sowing of 

 seed. Where seedlings 

 are to be grown by the 

 natural method, care must be taken to cut out enough of the 

 standing timber to facilitate the growth of the spruce at each 

 stage of its development. In time, most or all of the larger trees 

 of such an area will need to be cut, to allow the new spruce 

 forest to develop normally, with plenty of soil space and light 

 exposure. In other instances clear spaces are cut in the forest, 

 with bordering mother spruce trees, from which the seed will be 

 distributed and sown naturally over the cleared ground. In such 

 cases the surrounding trees, if the clearing is not too large, pro- 

 tect the ground from drying and furnish partial protection to the 

 growing seedlings. These sheltering trees must be allowed to 

 stand until the young growth can bear direct exposure. 



FIG. 227. Ripe cones of big-cone spruce in 

 the Cleveland National Forest, California 



Photograph by the United States Forest Service 



