MANAGEMENT PLANS THE NATIONAL FOKESTS 25 



The soil is rather shallow as a rule, except in the stream bottoms. On the 

 slopes it frequently contains a large amount of surface and slide rock. There 

 is more or less rock outcrop to be found on every ridge. The soil-moisture con- 

 tent varies from dry to fresh on the ridges and fresh to moist in the stream 

 bottoms. 



Small areas of white spruce {Picea glauca alhertiana) and aspen are found 

 in the central and northern parts of the circle. These species are not in suffl- 

 <3ient abundance, however, to be of commercial value. The principal species is 

 western yellow pine (Pinus ponderosa), which grows in pure stands over the 

 entire circle. 



The total area of forest-producing land within the circle, exclusive of the 

 small amount of timbered private land, is classified as follows : ^ 



Total forest-producing land, 167,258 acres ; reproduction, 29,412 acres ; poles, 

 28,008 acres ; merchantable, 109,838 acres ; inaccessible, 394 acres. 



The average stand per acre on the area covered by merchantable timber is 

 4,270 feet b. m. The best of the timber is found in the central and northern 

 part of the circle. Much of the stand in the southern part is of the scrubby 

 foothill type. The total volume of accessible merchantable timber within the 

 c-ircle is estimated at 468,969,000 feet b. m. 



Character of stand. — Three general age classes are found in the yellow-pine 

 stands in this circle. These classes, with the type symbols generally used to 

 designate them on the management-plan maps, follow : 



Class Symbol 



1. Reproduction (under 6 inches d. b. h.) 1-20 



2. Poles (6 inches and up to small thrifty "blackjack" trees) 20-80 



5. Merchantable timber (10 inches and up) 80-1- 



a. Mature and decadent, removed first cut. 

 6. Thrifty to mature, removed second cut. 



There is very little, if any, mature timber over large areas of the Upper 

 Hell Canyon and Bugtown blocks at the present time (1923) because of the 

 •depredations of the Black Hills beetle {Dendroctonus ponderosa Hopk.) between 

 1898 and 1910. Small patches of beetle-killed trees are found scattered through- 

 out the circle. Good stands of reproduction have come in, however, in almost 

 «very area where the mature timber has been destroyed by this insect. There 

 is little active infestation at the present time. 



The best timber within the circle is found in the north central part of the 

 Pleasant Valley block. Timber in the vicinity of Custer is good average pine 

 for the Black Hills. The foot hills timber in the southern part of the circle is 

 short boled, with a rapid taper. It grows more slowly than the average. 



The mature and decadent timber, class 3a, is as a rule very defective. This is 

 primarily due to rot entering through old fire scars at the base of the tree or 

 through rotten limbs on the bole. Deductions in scaling timber cut in sales 

 often amount to 25 per cent. After the first cutting cycle is completed, it is 

 estimated that the deductions will be reduced to not over 10 per cent. This 

 will have a marked effect on the volume obtained per acre. 



Natural reproduction is very good over the entire circle. It is best, however, 

 in the central and northern parts where growth conditions are most favorable. 

 On many areas the reproduction is so dense that stagnation occurs after 15 or 

 20 years. Heavy, wet snows cause a large loss through deformity (snow bend) 

 on such areas and have the same effect as a heavy but unskilled thinning. 

 Except on the very worst burns, reproduction is almost certain to show up in 

 three to five years after the fire. Even very bad burns, such as the one at 

 Mayo, reseed as a rule in 10 or 15 years. 



Cut-over stands vary considerably in silvicultural condition and volume, de- 

 pending on the original stand. As a general rule, about 70 per cent of the 

 original merchantable volume is removed. The following figures for timber 



2 These figures do not clearly indicate the true character of the stand, since the types 

 are classified according to the predominating age class found on the area when cruised. 

 Reproduction is found in varying quantities over the entire forest-producing area (with 

 very few exceptions). Numbers of trees of the pole class are ordinarily found under the 

 stands of mature timber. Such conditions are characteristic of the yellow-pine stands 

 throughout the Black Hills. 



65771—28 4 



