Notes on Growth of Pine Seedilngs. 297 



Arizona Pine, Mexican White Pine, 



{Pinus arizonica) (P. strobifonnis) 



Seedling No. 1 I 1-8 inches Seedling No. 1 11-8 inches 



Seedling No. 2 1 3-8 inches Seedling No. 2 1 inch 



Seedling No. 3 1 1-8 inches Seedling No. 3 1 1-2 inches 



Seedling No. 4 7-8 inches Seedling No. 4 7-8 inch 



Seedling No. 5 13-16 inches Seedling No. 5 7-8 inch 



Seedling No. 6 1 3-16 inches Seedling No. 6 3-4 inch 



Seedling No. 7 1 inch Seedling No. 7 13-8 inches 



Seedling No. 8 1 3-8 inches Seedling No. 8 7-16 inch 



Seedling No. 9 1 inch SeedUng No. 9 7-8 inch 



Seedling No, 10 1 3-16 inches Seedling No. 10 1 1-8 inches 



The long, straight tap roots that the seedHngs had sunk 

 were, at the end of three years, at least from four to eight times 

 as long as the portion of the plant above ground. This char- 

 acteristic feature of most of our western perennials proves that 

 the young trees were by no means idle, but were sinking securely 

 the foundation for future growth. But all of this takes time. 

 All these seedlings began growth in the spring or summer of 1907. 

 None were found to have started since that date, or several 

 years preceding it. Indeed, it is a known fact that pines in 

 general reproduce in certain years only. The right kind of seed, 

 soil, and weather must meet before a new generation unfolds 

 itself. It is by such slow and uncertain methods, yet in the 

 long run and over a wide scope thoroughly effective, that the 

 forest naturally reproduces itself. The process may be assisted 

 by human protection. Recent extensive fires in the Santa Cata- 

 lina Mountains have destroyed vast numbers of pine and fir 

 seedlings that were already well established in nunv parts of 

 the forest. \'egetative conditions here being more favorable 

 than in the Rincons these seedlings probably had enjoyed a 

 somewhat more ra;:id growth than those measured aboye. 

 But even here the cost of raising and replacing by hand all the 

 trees destroyed would amount to millions of dollars in time and 

 direct outlay. 



Tucson, Arizona. 



