FOREST FIRES. 121 



similar soft woods, but even hard woods are injured by 

 insects if allowed to stand long after being killed. 



The Killing of Half-Grown Trees by forest fires causes a loss 

 that amounts not only to the value of the timber trees but to 

 the value of the seeding and shading trees and the forest 

 floor. The value of the trees alone in this case is not a fair 

 standard by which to measure the loss, since at this stage of 

 their growth they are making their most rapid increase and 

 their value should be computed as the amount upon which the 

 increase is paying a good interest. For instance, the Divi- 

 sion of Forestry of the Minnesota Experiment Station found 

 land that was well stocked with young White Pine ( six inches 

 in diameter and fifty feet high ) that could be bought for about 

 one dollar per acre, and yet the annual increase on the trees 

 would paj five per cent on a valuation of $100,000 for the next 

 twenty years. The reason why ^uch a state of affairs exists 

 is that there is such great danger from fire that the invest- 

 ment fails to command the money of careful investors. 



The Destruction of the Forest Floor by fire greatly lessens the 

 probability of an immediate renewal of valuable tree growth 

 upon the land and therefore is one of the greatest injuries to 

 forests. The value of the forest floor can hardly be estimated 

 but the expense that would be necessary after a fire to produce 

 conditions as favorable to the seeding of our timber lands as 

 those found in unburned forests would probably be not less 

 than twenty-five dollars per acre. 



Light Fires which repeatedly run over the ground and which 

 by the casual observer are thought to be of no importance 

 often destroy the seeds in the surface soil and the young tree 

 seedlings besides injuring the forest floor, and unless such 

 fires are prevented it is impossible to secure a good growth 

 of timber on any land. The fires that burn over the land 

 shortly after it has been logged and which feed on the tops 

 and other waste parts of the trees, generally destroy a large 

 number of young seedling trees, perhaps all of them so that 

 in order to secure a new growth seeds must be brought from a 

 distance. Owing to the great heat developed by such fires in 

 dry weather, they are unusually destructive and leave very 

 little humus in the top soil. For this reason land that has 



