1904 



FORESTRY AND IRRIGATION 



507 



ally the cones open and permit the seed 

 to drop to the ground the very au- 

 tumn they mature. A slight surface 

 fire, then, is sufficient to kill all the 

 seeds and sprouts. The thick-scaled, 

 serotinous cones of the lodgepole pine 

 remain closed under natural conditions 

 for several years. As is usually the 

 case, a surface fire, or often a quite 

 severe fire, does not affect or suffi- 

 ciently burn the cones to prevent them 

 from carrying the seed through the 

 fire ; later the cones open and liberate 

 the seeds, and re-seeding takes place 

 from the standing fire-killed trees 

 more certainly and rapidly than is 

 usual by spruce and fir from living 

 trees. The heat from a surface fire 

 may burn a portion of the trees, and 

 a part, if not the whole, of the top. 

 may be heated, but not burned, and 

 the cones begin to open so the seeds 

 are in time set free. Of course, a 

 great many of the seeds reaching the 

 ground fail to germinate, but the 

 quantity shed is so great that a suffi- 

 ciently thick stand of reproduction is 

 always assured. 



As the tree fruits every year, nearly 

 all standing trees are loaded with a 

 crop of cones, the side branches as 

 well as the crown portion producing 

 them. It is easy to imagine the im- 

 mense quantities of seed from a whole 

 forest when all these cones liberate 

 their seed at practically the same time. 

 It is not surprising then to understand 

 the cause of the dense lodgepole re- 

 production on burned over areas. 



The reappearance of lodgepole pine 

 over burned land, originally occupied 

 by itself, is doubly assured, because re- 

 seeding may take place not only from 

 living trees, but also from the standing 

 fire-killed trees. The reproduction of 

 lodgepole is still further ascertained, 

 because of the early fruiting of young 

 trees. Fully mature cones have been 

 found on small trees five to eight feet 

 high, and from ten to fifteen years of 

 age. Lodgepole extends its area be- 

 yond the original one a considerable 

 distance on all sides. This continual 

 process of renewing itself on the same 

 ground after burns may go on Tor 



generations ; trees of different ages, 

 bearing fire scars at different periods, 

 indicating three of four separate 

 crops, are found standing in isolated 

 places overtopping the dense young 

 growth. 



From sample acres, on which repro- 

 duction studies were made, the number 

 of specimens varies greatly, but it 

 would be safe to say that the average 

 acre of reproduction on a burned 

 over area contains 15,000 specimens. 

 As an illustration of the density of 

 seedlings, on a gentle north slope at 

 an altitude of 6,600 feet in a moder- 

 ately deep sandy loam soil, a sample 

 acre of lodgepole reproduction ga\e 

 by actual count 17,968 seedlings. 

 Again, on another acre in a different 

 locality, but soil and situation practi- 

 cally the same, 13,632 individuals were 

 counted. These seedlings were grow- 

 ing in the open, over a burned are?., 

 among considerable dead and down 

 wood, which was not completely con- 

 sumed by fire. The average age was 

 fourteen years, varying from nine to 

 sixteen ; the mean height of the seed- 

 lings measured three feet. Many of 

 these small trees were beginning to 

 bear cones. 



When the leafy canopy overhead is 

 not too dense, and when some light 

 comes in from the sides, reproduction 

 under partial shade may take place. 

 A good example of this was observed 

 in Park County, Montana, where on 

 a steep hillside facing an open mea- 

 dow on the north, grew some fairly 

 thick patches of reproduction under 

 tall mature pines. A severe fire had 

 passed over this region about twenty- 

 five years since and left only the larg- 

 er pines. These pines were badly in- 

 jured by fire, yet continued to grow, 

 and" at the time observed the fire scars 

 had almost healed over. When the 

 fire passed over this region, many 

 cones were opened by the heat, and the 

 seeds, liberated, were left on the 

 ground to germinate. The larger trees 

 which survived the fire still continued 

 to furnish some seed, and because of 

 the light from the sides and loose 

 canopy overhead, the seeds started and 



