LIFE HISTORY OP LODGEPOLE PINE IN ROCKY MOUNTAINS. 15 



cutting on which reproduction is not taking place. Observations on 

 32 separate tracts in the 20 and 30 year age classes on this Forest show 

 a far more satisfactory reproduction on unburned cut-over areas 

 than where stands have been killed by fire. On many clean-cut areas 

 which have been left practically without seed trees reproduction has 

 taken place solely from cones which remained on the ground after 

 logging. Nearly all mature trees bear a considerable number of per- 

 sistent, closed cones, some of which fall on the ground when the tree 

 is cut, while others remain attached to the branches. These gradu- 

 ally open and drop their seed, resulting in fairly uniform reproduc- 

 tion if the brush is scattered. If it is piled in windrows, which decay 

 very slowly, the spaces so occupied will not reproduce. (Plate IV, 

 fig. 1.) Where the stand is not cut clean, or where clean-cut only 

 over small areas, seed comes from above or from the side, as well 

 as from the^cones left on the ground and in the tops of felled trees. 

 Sample plots in an unburned stand on the Arapaho National Forest, 

 measured six years after the removal of about one-half of the original 

 trees for ties, showed an average of 6,000 seedlings per acre, of which 

 3,500 had started since the cutting. Even with the same number of 

 seedlings per acre reproduction is apt to be more satisfactory on an 

 unburned than on a burned area, since the young growth comes in 

 more gradually, giving trees of different heights and so materially 

 lessening the danger of stagnation. 



The greater part of the reproduction which comes in after either 

 fire or cutting usually starts within a comparatively short time. The 

 following figures, which represent averages obtained from 181 small 

 sample plots, both burned and unburned, in Montana and Wyoming, 

 show the proportion of reproduction which came in during each 

 5-year period for the first 30 years after the stand was opened up : 



Per cent. 



First five years 69.5 



Second five years 21. 



Third five years 5.4 



Fourth five years .9 



Fifth five years 2.5 



Sixth five years . 7 



100.0 



It will be seen that nearly 70 per cent of the reproduction started 

 in the first 5 years and over 90 per cent in the first 10 years. Unfor- 

 tunately, it is not possible to separate the figures for burned and 

 unburned plots. Similar observations on a 9-year-old burn on the 

 Arapaho National Forest showed over 49 per cent of the reproduc- 

 tion to have started in the first four years and nearly 75 per cent in 

 the first six years after the fire. In most places the character of the 

 seedbed is so changed in the 10 years following a cutting or fire by 



