46 BULLETIN" 234, U. S. DEPARTMENT OF AGRICULTURE. 



become old enough to bear fertile seed, usually in 15 or 20 years. 

 Planting by this method would require from 125 to 150 seedlings per 

 acre, and should cost about $2. 



PROTECTION. 



FIRE. 



Although fire is the principal agent in aiding lodgepole pine to 

 maintain its existence in many places, it is also the most destructive 

 agent in mature lodgepole-pine stands. Besides the active measures 

 taken to prevent and extinguish fires, such as lookout stations, 

 telephone lines, roads and trails, patrol, and the like, certain coor- 

 dinate lines of forest work may be handled in a manner to insure 

 that the fire danger will be kept at the minimum. The most impor- 

 tant of these in the case of lodgepole pine is the gracing of live stock, 

 particularly sheep. In the lodgepole-pine region fire almost inva- 

 riably spreads by means of grass and weeds. A grass fire travels 

 very rapidly and soon spreads over large areas. The grass of the 

 lodgepole-pine region becomes sun-cured early in July and dries 

 very rapidly after summer showers which dampen other inflammable 

 material for several days. Thorough grazing on the dangerous areas 

 by sheep would dispose of most of the inflammable material. Old 

 grass left over from the previous year is particularly inflammable 

 and makes a very hot fire. Particularly heavy grazing along trails, 

 secondary ridge tops, and certain section lines would be a means of 

 securing fire lines at frequent intervals. When grazing in the timber 

 sheep trample and wear out the down litter and other debris, greatly 

 hastening its decay. 



In addition to the grass which grows in and near the timber, pine 

 needles and other debris form an inflammable ground cover. A fire 

 in needles alone travels slowly and is easily controlled. Where, 

 however, there is also a considerable amount of debris, such as old 

 tops and down timber under dense young stands, the heat from below 

 sometimes starts crown fires, though this is rare in lodgepole pine. 

 Fires on cut-over areas where the brush has been piled and burned 

 are easy to control. Where the brush has been well piled and not 

 burned there is danger of a hot fire which will kill many green trees 

 near the piles. Such a fire is harder to handle, of course, than one on 

 a cleaned-up area, but it is by no means as hard to handle as one on 

 an area where the slash is left in windrows or scattered over the 

 ground. Roads and skidding trails constructed in connect ion with cut- 

 tings and thinnings will act as fire breaks. Much less debris is likely 

 to accumulate in the well-spaced, moderately open stands which 

 come up after cutting than in the over-dense stands resulting from 

 fire. By the time the lodgepole-pine region has been cut over once 

 under Forest Service regulations, with the proper amount of grazing, 

 the fire danger will have been very much reduced, even though no 

 further advance is made in other means of prevention and control. 



