294 



SEEDING AND PLANTING 



top of the posts forming a framework over which the cover is dis- 

 tributed in sufficient quantity to permit half shade to reach the 

 seedbeds beneath (Fig. 69). 



A more substantial but more costly form of high cover has been 

 extensively used in the nurseries in many of the National Forests. 



FIG. 69. High cover formed of brush on a framework of 

 posts and poles. 



In this form the framework is covered above, or both above and 

 .on the sides, with lath or narrow slats spaced so as to give the de- 

 sired cfegree of shading (Fig. 70). 



High cover has some advantages over low cover but in most 

 localities they are more than counterbalanced by decided dis- 

 vj advantages including greater cost. The greatest objection to the 

 I high cover is the difficulty in shifting it with changes in weather 

 \ conditions. Furthermore, it does not permit the rotation of seed- 

 lings with transj'ants or field crops because of the expense in 

 moving it to other parts of the nursery. 



High cover should be used only in localities where there is no 

 need for regulating the density of the shade with changes in 

 the season and weather. The seedbeds under high cover vary 

 in width from 3 to 7 feet, with 1J- to 2-foot spaces between for 



