146 ECONOMICS OF FORESTRY. 



the seed only when fire, which has probably de- 

 stroyed all competitors, opens them. The pecu- 

 liarities of the seed, then, account for much in the 

 distribution of plants. 



Next comes the peculiarity of growth. The 

 long-leaf pine, which, for the first four years, does 

 not grow more than two or three inches above the 

 ground, is at a disadvantage in that first period, 

 during which it has occupied itself with forming 

 a stout root system; but thereafter, by virtue of 

 this root system, it may endure what a faster- 

 growing neighbor could not. The quickly growing 

 aspen covers large areas, but its reign is of short 

 duration, for, as with most of the rapid growers, 

 its life is short. The slower-growing spruce, which 

 could support itself under the light shade of the 

 aspen, remains on the field, the victor by sheer 

 persistency. 



Capacity to resist unfavorable weather condi- 

 tions frost and drought will give the advan- 

 tage to one species over the other, while liability 

 to attacks by animals, especially insects, may also 

 prove disadvantageous in comparison with the 

 others. There is little doubt in the mind of the 

 writer that the big trees, the Sequoias, owe their 

 long life to their immunity from insects and fungi 

 and to their resistance to fire, to which their com- 

 petitors succumb. Finally, however, the two qual- 

 ities first mentioned, relative height growth and 

 relative light requirement, are determinative. 



