THE PRINCIPLES OF FORESTRY 183 



The nuts of black walnut, hickory, chestnut, and others, 

 and the pits of the plum, peach, and cherry should be either 

 spread between layers of moist sand or planted in the fall 

 where they are to grow. They should not be allowed to dry 

 out after ripening. The larger nuts may be planted while 

 doing shallow plowing, by dropping them in a furrow and 

 covering them with the next furrow slice. 



The deep root system formed by most of the true nut- 

 bearing trees makes them difficult to transplant, even when 

 young. 



FIG. 90. Lattice supported on poles. Such a structure gives alternate light and 



shade in growing forest seedlings, tobacco, ginseng, and a few other plants. 



(Plant Industry.) 



Seeds that ripen in spring and early summer should be 

 planted within a few weeks, as they live but a short time. 

 The American elm, soft maple, and cottonwood are examples 

 of this group, but the red elm is an exception, as the seeds 

 will not sprout until the next spring. 



Seeds of trees that ripen in the fall, except the evergreens, 

 may be planted either the same fall or the following spring. 

 If planted in the fall they should be covered with a leaf 

 mulch and also protected from squirrels and other animals. 



The cone-bearing trees, including the pine, spruce, tama- 

 rack, and white cedar are started from seed sown in the 

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