MANAGEMENT PLANS THE NATIONAL FORESTS 73 



the yellow-pine type a group-selection system of marking is applicable. In the 

 two higher types a straight-selection system, guided by a diameter limit, has 

 toeen in use and has been found effective. 



Advanced reproduction is well established over the entire area, so that 

 barring fires or insect attacks, a fully stocked stand, for the second rotation is 

 assured. In the yellow-pine type, pine reproduction predominates. Therefore, 

 the stand during the second rotation will be identical with the original forest. 



In the Douglas fir stands, white-fir reproduction greatly outnumbers the 

 smaU Douglas fir. In such stands it has been the practice to make rather 

 heary. openings. On the theory that Douglas fir will outstrip its associate 

 white fir in the race for dominancy where given full top light. This theory has 

 neyer been proved correct and further observations are necessary before exact 

 Imowledge can be available. However, it is the writer's opinion that if a 

 stand is cut when a d. b. h. of 15 inches is attained, the percentage of white 

 fir in the replacement stand will be much greater than it was in the original 

 stand, in which Douglas fir has gained the upper hand as a result of its longer 

 life. (White fir is very susceptible to a heart rot which causes rapid deteriorat- 

 ing in trees over 16 inches d. b. h.) 



The same condition is found in the spi"uce type, in which cork-bark fir seed- 

 lings far outnumber the more desirable Engelmann spruce. In this case, like- 

 wise, it is thought that cork-bar fir will form a large percentage of the stand 

 If it is cut on a short rotation basis, as is contemplated. 



The stand of poles and saplings left after the first cut in the original forest 

 is largely made up of the more desirable Douglas fir in the former type and 

 Engelmann spruce in the latter. The range of diameter classes is suflSciently 

 large to provide a cut of species in about the same proportion as occurred in 

 the virgin stand for at least the next two cutting cycles. The change in the 

 composition of the stand will not occur until the present advanced reproduc- 

 tion reaches merchantable size, which will be in about 90 years. 



At the present time about half of the forest area is classed as nonproduc- 

 tive. Much of the area included within this nonproductive classification is 

 stocked with immature timber. In the true sense of the word the area is not 

 unproductive, but it carries no mature stands, hence has not entered into the 

 -calculation of yield for the first cutting cycle. In the drafting of future 

 plans this area will play an important part. 



(c) Situation as to fire. — During recent years there have been no large fires 

 within the spruce stands. In the past great fires have swept over portions of 

 this area and killed every tree. Probably the old fires ran through stands 

 which had been killed or at least weakened by some pest, such as the spruce 

 bud worm. 



Following logging the resulting debris naturally creates a big risk. 



Fire starting from lightning is the greatest danger. However, carelessness 

 on the part of the employees of operators may possibly be the cause of a fire's 

 getting loose. 



The smokestacks on each of the mills are amply guarded with spark arresters, 

 and little or no danger is anticipated from that source. 



The burning of slab piles must be carried on with the greatest care, but 

 this danger is fully appreciated, and proper precautions are being taken to 

 prevent the escape of fire. 



A good automobile road from Taos to Las Vegas is now being built through 

 the working circle. When the road is completed there may be some danger 

 from campers being careless with fire. 



The comparatively large amount of rainfall, the frequency of showers during 

 the summer, and the long period during which snow lies on the ground combine 

 to make the danger from fire in the Rio Pueblo working circle as small as in 

 any stand in the national forests of Arizona and New Mexico. 



(d) Groivth and yield. — Studies to determine the average rate of growth of 

 the most important individual species found in the area have been carried on. 

 The results of these investigations are found in the report the " Growth and 

 yield data of the important timber species in northern New Mexico." 



In formulating the plan of management it is necessary to know the average 

 number of years required to produce a 14-inch tree. The following figures are 

 taken from Tables 8, 10, and 12 of the report above referred to to produce 

 trees of 14-inch d. b. h. : Western yellow pine, 120 years ; Douglas fir, 146 years ; 

 Engelmann spruce, 115 years. 



