REPRODUCTION OF WESTERN YELLOW PIXK 28T 



Some areas bear excellent seedling or sapling growth, but the bulk of 

 this was on the ground at the time of cutting. This situation gives 

 rise to apprehension regarding the future of cut-over lands. The stud- 

 ies which have been made, however, indicate that reproduction, while 

 by no means certain, is likely to come ultimately. The period may be 

 30 years or even longer, depending upon a large number of circum- 

 stances. These conclusions are based upon results on old cuttings in 

 which the stand was left in approximately the same condition as on 

 present-day Service cuttings. A study of the table reveals the fact that 

 the poor reproduction is due not so much to a lack of germination as 

 to a high rate of mortality among young seedlings. Excepting in plot 4. 

 fair crops of seedlings have started from time to time, but they have 

 failed to establish themselves in adequate numbers. The same story is 

 told by other plots and by general observation on cut-over areas and in 

 virgin stands alike. In 1910 and 1914 good, though not dense, stands 

 of seedlings sprang up quite generally on the Coconino National Forest, 

 but today the survivors, except in favored localities, are very few. 



Most of the seedlings die during the first season. ( Termination does 

 not take place until the advent of the summer rains, in July and Au- 

 gust, and consequently the seedlings make only about two months' 

 growth the first year. If the summer rains are regular and if the 

 autumn is not too dry, they get a fairly good start, but such conditions 

 are exceptional. Innumerable seedlings die from temporary droughts 

 in the rainy period. Those which survive are subjected to a further 

 trial in September and October, when they are endangered not only by 

 drought but also by frost. 



In addition to the short growing season, the development of seed- 

 lings is further retarded by compact soils, which resist penetration by 

 tender roots. An investigation at the Fort Valley Experiment Station 

 in 1917 showed root lengths for natural western yellow-pine seedlings 

 as follows: One-year-olds, average 6.4 inches, maximum 9.5 inches; 2- 

 year-olds, average 9.2 inches, maximum 12.7 inches; 3-year-olds, aver- 

 age 10.5 inches, maximum 14.2 inches. In most years the soil moisture 

 during the month of June is reduced to a point where it is no longer 

 available to plants in the soil strata reached by the average i and 2 

 year old seedlings. Thus it is only the exceptional individuals of the 

 I and 2 year classes which have a chance to survive, and in extremely 

 dry years even 3-year-old seedlings are taxed tt) the utmost. Since 

 nursery-grown seedlings commonly attain a root lengtii of 10 to 12 

 inches in the second year, the slow development under natural condi- 

 tions mav be attributed to the compact adobe soil characteristic of the 



