EEPRODUCTTOX OF WESTEEN YELLOW PINE. 



95 



the original ones give values of 6.5 per cent at a depth of 2 inches, 

 8.9 per cent at a depth of 6 inches, and 12.5 per cent at a depth of 

 12 inches. The 6-inch coefficient is probably approximately correct 

 for the 4 to 8 inch moisture samples. 



Table 22.- 



-Total soil moisture {percentaije of dry weiylit), brush c-rpcriincnt, 

 cinder area, 1909 and 191.2. 





1909. 





May 1. 



May 29. 



Julys. 



Aug. 5. 



Sept. 4. 



Oct 



.4. 





c„- 



^ 



fR 



«• 



i 



i 





i 



i 



^ 



i 



!fi 





^ 



M 



Xi 



^ 



xt 



ja 



xi 



xi 



xi 



Xi 



xi 



xi 































a 





^ 



a 



.3 



ti 



d 



.3 



a 





c 



fi 



























•* 



oc 



-* 



X 



tH 



00 



TJ< 



oc 



Tl< 



00 



-# 



00 





o 



o 



o 



o 



o 



o 



o 



o 



o 











































o 



■* 



o 



■* 



o 



^ 



o 



■* 



o 



^ 







^ 



Dense brush 



14.6 

 7.1 





9.6 

 2.9 



14.2 

 10.8 



6.5 

 5.4 



11.7 

 8.7 



13.3 

 10.0 



16.8 

 14.2 



21.2 

 21.0 



21.5 

 21.7 



16.4 

 10.9 





No brush 











1909. 



1912. 





Nov. 6. 



June 11. 



June 26. 



July 12. 



Aug. 7. 



Sepf 



. 12. 











i 



. 













. 



. 





























ja 



.a 



^ 



Xi 



■"1 



.c 



X3 



Xi 



XI 



Xi 



M 



Xi 

































p 



;3 



c 





r^ 



d 



a 



c 





c 



.3 





























•^ 



X 



Tjl 



oc 



■* 



X 



•* 



00 



■* 



00 



"* 



00 





O 



o 



O 



o 



o 



o 



o 



o 



o 









































o 



■* 



O 



Td 



o 



^ 



o 



^ 



o 



■* 







^ 



Dense brush 



6 9 



10 6 



11 



12 3 



6 4 



9 2 



4 5 



6 8 



14.5 



14.5 

 14.3 

 15.3 



7.0 

 5.9 

 5.5 



7.4 

 7 



Light brush 







10.0 

 9.4 



12.6 

 11.2 



4.1 

 5.1 



8.5 

 7.2 



2.4 



3.8 



6.1 

 5.3 



19!' 

 15. 



No brush 



3.6 



9.6 



8.7 





Both the 1909 and 1912 series show a substantial margin in favor 

 of the brush cover during the foresummer. After the summer 

 rains are well in progress, all values are so high that minor differ- 

 ences are insignificant. There is, however, a tendency for the 

 moisture content to be lower at times under the cover, due no doubt 

 to interference with rain reaching the soil. In the autumn the 

 margin in favor of the brush appears to be uncertain. The 1909 

 series shows a difference of but 1 per cent at 4 to 8 inches on No- 

 vember 6. In 1912 the balance was actually in favor of the open 

 areas. At the time this relation was first observed it was thought 

 to be due to abnormal samples or some error in determining the 

 moisture content, but more recent experience has shown such occur- 

 rences to be not uncommon. The explanation is found in the ac- 

 tivity of grass and other vegetation. Usually all plants are killed 

 directly under a heavy mass of brush, but survivors in the margin 

 of the brush develop extraordinary luxuriance, with the result that 

 they may reduce the soil moisture to a lower level than that which 

 prevails at some distance from the brush. This condition is more 



