H 



JULIUS VALENTINE HOP MANN 



was undisturbed. The object was to find the influence of ground cover 

 following a burn or clearing. The results are summed tup in Table IV. 



TABLE IV 

 NATURAL COVER AND DENUDED AREAS 



Air temperature taken at crown on one-year-old seedlings. 



Table IV shows clearly the effect of evaporation from surface soil when 

 denuded, also the greater per cent of soil moisture at the 6-inch and 12-inch 

 depths as compared with these same depths in the area having the natural 

 ground cover of wild pea vine and brush. Although the surface dried 

 out on the denuded area, the 6-inch and 12-inch depths still contained 

 more moisture than in the area of the natural cover, due to the moisture 

 being taken out of the soil by the roots and evaporated from the leaves in 

 the area under natural cover. 



The hot, dry surface soil shown in Tables II and IV accounts for the 

 loss of one-year-old seedlings on these exposed slopes, while the moist, 

 cooler surface under plant cover gives the young seedlings protection. 

 The greater amount of moisture in the 6-inch and 12-inch depths on the 

 denuded area and exposed slopes also shows why seedlings with deep roots 

 early in their development will succeed on such slopes. 



The following plates show the size of seedlings of various species of 

 conifers up to one year of age. As will be noticed in the plates, the size 

 of the seed influences directly the size of the seedling in its early life. 



