THE FOREST NURSERY 



287 



is available as they bring in weed seed and increase the cost of 

 later cultivation. It is often necessary to place brush, lath screens, 

 or other suitable material on the mulch to prevent its disturbance 

 by the wind (Fig. 65). When the seedbeds are adequately 

 moistened before mulching, it is often unnecessary to water them 

 before germination starts. When water is needed it is applied 

 over the mulch. One advantage of mulching arises from its 

 effect on the growth of weeds. The weed seeds that germinate 

 before the tree seeds grow upward into the mulch and are thus 

 destroyed. The mulch must be removed as soon as germination 

 starts. 



24. COVERING WITH SCRIM, CHEESE-CLOTH, OR BURLAP. - 

 Scrim, cheese-cloth, and burlap are extensively used for protecting 

 seedbeds prior to germination in many large nurseries in the 



FIG. 66. Seedbeds covered with burlap after broadcast seeding. 



United States (Fig. 66) . Where nursery operations are conducted 

 on a large scale this manner of protection is usually more satis- 

 factory and often less expensive than covering with brush or 

 mulching with leaves, due to the facility with which they can be 

 placed over the beds and later removed. They have the added \ 

 advantage of not introducing weed seed as is often the case when 

 mulch is used. Furthermore, the soil warms up more quickly and 

 germination is earlier. This is of great advantage in high altitudes 

 and other localities where the growing season is short and when 



