TREATMENT OF SEEDING AND PLANTING SITES 205 



plowed land the young trees from the first show considerable 

 variation in height growth, and, as a result, when the canopy 

 closes the competition is not so intense and early thinnings are 

 not so essential. 



21. Treatment of Areas Covered with Shrubby Vegetation 



Vast areas in the National Forests and in other parts of the 

 United States are covered with a growth of low woody plants. 

 The value of this vegetation lies chiefly in the protection which 

 it affords the soil and in its effect upon the surface flow of water, 



Although in some localities, as in the foothills of southern 

 California, this type of vegetation occurs where the site factors 

 are too adverse for forest growth, in the aggregate enormous areas 

 throughout the country that are perfectly capable of sustaining 

 forests of large economic importance are given over to an almost 

 worthless growth. Thus, in eastern Pennsylvania large areas are 

 covered with a dense growth of scrub oak (Quercus nana) seldom 

 over 6 to 10 feet in height. 



The problem of transforming these shrub-covered areas into 

 profitable forest is one of large importance. In semiarid regions 

 where the natural vegetation is chaparral, the transformation can 

 seldom be made without first removing the chaparral. Burning 

 or cutting it does not suffice as it quickly coppices from the root 

 and overtops the young trees when planted. Planting or seeding 

 beneath the chaparral seldom, if ever, results in a successful stand. 

 It must usually be grubbed out root and branch, which necessitates 

 an expenditure of from $50 to Si 00 per acre, a sum rarely, if ever, 

 justified under present conditions. 



In the brush-covered areas of more humid regions that were 

 formerly covered with forest, the problem is not so difficult. If 

 protected from fire, they ultimately become reclothed with timber. 

 The time required, however, is often so long that it is desirable 

 to bring the regeneration about by artificial means. When the 

 brush cover is open and composed of thin-foliaged plants regen- 

 eration is often possible without the removal of the vegetation. 

 The problem of artificial regeneration is far more difficult on areas 

 covered with scrub oak and other species that form dense thickets 

 in almost pure stands. Large transplants of hardy, rapidly-grow- 

 ing species should be used. Direct seeding should be avoided. 



