106 BULLETIN 1105, U. S. DEPARTMENT OF AGEICULTUEE. 



Table 25. — Seedling survival in relation to method of brush disposal — Continued. 



B. EXAMINATIONS IN OCTOBER, 1921. 





Basis. 



1919 seedlings. 





Number 

 per acre. 



Large. 



Injured 

 grazing. 



2. Sample plot 3B; logged 1909; heavy bunch-grass: 

 Inside fence, ungrazed— 

 Natural areas 



Sq.feet. 

 192 

 192 



300 

 300 



200 

 200 



12,000 

 35,000 



5,800 

 1,600 



13,300 

 21, 800 

 22,300 

 4,200 



1,440 



530 







1,520 



1,090 



3,370 



1,120 



740 



1,590 



Per cent. 

 24 

 30 



27 

 18 



Per cent. 

 



Burned brush piles 







Outside fence, grazed s— 



Natural areas 



27 



Tops (windfalls, 1915) 







8. Section 22, Fort Valley; virgin stand; moderate herbaceous 

 cover; closely grazed by cattle; few sheep: 

 Naturalareas 



13 



Scattered brush 





9 



Naturalareas. 



20 

 29 



11 











583 



5 100 



14 

 12 

 14 

 33 



5 



Tops (-svindfaUs, 1915) 









9. Sample plots 5 II and III; logged 1913; grass variable; fenced; 

 grazed by horses only: 

 Natural areas, bunch-grass 



560 

 660 

 660 

 660 

 520 

 640 

 640 

 410 

 410 



6 



PioUed tops, bunch-grass .. .. 







Natui'al area?, bare * 





PuUed tops, bare 1 







Scattered brush, bare <. 







Natural areas, bunch-grass 



10 



Scattered brush, bunch-grass 







Natural areas, bunch-grass 







Burned brush piles 











' At least 25 per cent estimated killed by grazing on natural areas, but none in tops. 



* Overgrazed clay flat. 



5 Most of these are of extraordinaiily large size. 



After the first plots revealed the creneral trend of the data, a 

 second examination showed that invariably, where seedlings were 

 much less numerous in the brush, the grass was taller and more lux- 

 uriant in the brush than in the open, and that where the seedlings 

 were equally or more nmnerous in the brush, it was invariably on 

 areas on which the ground cover was sparse, because of overgrazing 

 or some other abnormal condition. The explanation is simple. 

 Seedlings thrive best where they are not forced to compete with 

 other vegetation. Brush interferes more or less with grazing. It 

 also favors growth by checking evaporation and, in some cases, by 

 adding organic matter to the soil. These benefits, however, the older 

 and more aggressive grasses and weeds are able to take advantage 

 of more fully than young pine seedlings. Consequently, the pine 

 seedlings growing in brush must meet more severe competition than 

 those growing in the open where the herbaceous vegetation is kept 

 down by grazing. But where the natural ground cover had been 

 killed out prior to the placing of brush, as on severely overgrazed 

 areas, roads, and stump patches, the pine seedlings have practically 

 no competition. The relation with respect to number of seedlings 

 also applies to size; that is, the smallest seedlings occur in brush 

 where the grass is unchecked, and the largest occur in brush where 

 there is no grass or other competing vegetation. 



