Destruction and Deterioration 115 



from adjoining coniferous areas spread and destroy 

 the broad-leaved trees. In all parts of the country, 

 coniferous trees, the pines and spruces and their 

 kin, are most liable to fire. One must not imagine 

 that a single fire often destroys large quantities of 

 large, vigorous timber. Top fires, — that is, fires 

 which reach the crowns of trees, spread from branch 

 to branch, and consume the whole tree, leaving at 

 most a charred, dead remnant of the trunk stand- 

 ing upright like a blackened ruin until the wind 

 overthrows it, — are the exception. The ordinary 

 fire is a surface fire, eating up the litter on the 

 ground, the feebler undergrowth, and the young 

 trees, and only scorching more or less severely the 

 large timber. If a fire of this nature is very hot 

 it may even kill the large trees, without, however, 

 consuming them. In such a case, much of the 

 timber can be saved if it is cut at once, before 

 fungi and insects have destroyed the wood. Fires 

 of this kind do their greatest harm by making 

 it impossible for trees to reproduce themselves, 

 because the young trees are killed or even the 

 seeds destroyed in the ground. It is remarkable, 

 by the way, how much heat some tree seeds can 

 stand. The cones of the jack pine (Pinus divari- 

 cata. Ait), for instance, remain on the trees some- 

 times for several years without shedding their 

 seeds. When a fire burns over the ground, the 

 heat causes the cones to open, and the seeds fall 

 on the hot ground. Yet these scorched seeds often 

 survive and bring forth seedlings. 



