If the North Slope were to be brought under management as a sustained yield unit, 

 the task would be difficult because the age distribution is unbalanced and is dominated by 

 overmature stands. More than half of the coniferous forest bears stands that are mature 

 or overmature. Much of this timber is more than 200 years old, and a few stands are 3 or 

 4 centuries old. Annual losses are consequently high. 



The situation is likewise unsatisfactory at the other end of the age scale, for there are 

 very few young stands. Stands less than 60 years old occupy only 23,000 acres, and there 

 is a very small area of timber less than 20 years old. 



The bulk of the younger timber is from 60 to 100 years old. Most of these stands 

 were established following tie cutting and subsequent fires before 1900 (table 5). 



As in every other locality where there is much lodgepole pine, overstocking has creat- 

 ed a principal management problem. This is not readily evident in present classifications, 

 which indicate that only 13 percent is overstocked by basal area standards (table 6). How- 

 ever, a much greater area apparently was overstocked earlier in the life of present stands. 

 This is shown by diameters of trees in relation to their age. For example, about 146,000 

 acres of lodgepole pine poletimber that are classed as medium or well stocked (by all sizes 

 of trees) are actuaUy only poorly stocked with larger or pole-size trees. Yet these stands 

 are old enough to have a good stocking of poles. 



Table 5. — AREA OF CONIFER FOREST BY AGE CLASS 



Age class 



(years) 



Acres 



- 19 



3,233 



20 - 59 



19,807 



60 - 99 



97,301 



100 - 139 



50,628 



140 + 



211,831 



Total 



382,800 



Table 6. — AREA OF COMMERCIAL FOREST BY STOCKING CLASS 



Stocking class 



Acres 



Percent 



Overstocked 



52,121 



13 



Well stocked 



140,478 



35 



Medium stocked 



184,574 



45 



Poorly stocked 



24,074 



6 



Nonstocked 



2,452 



1 



Total 



403,699 



100 



The effect of overstocking in the past is also indicated by an estimate that almost 

 one-fourth of the mature lodgepole pine stands are of less than sawtimber size. Some of 

 these are on very poor sites, which accounts for the very small size of the trees but in many 

 other cases the situation is simply the result of overcrowding. Often a natural but tardy 



7 



