Mistletoe Control 569 



trees when isolated or left in seed plots may exhibit this deficiency 

 in seed production before the allotted time for an adequate reseed- 

 ing has expired. 



No one questions the expenditure of large sums for the control 

 of fire. The effect of a heavy infection by mistletoe over large 

 areas results in a great loss in increment which, when coupled 

 with other defects caused by the parasite, is analogous in some 

 respects to the immediate destructiveness of fire. It is well 

 known that fire when not causing death directly precedes serious 

 injury by fimgi and insects due to a weakening of resistance to 

 these agents. Mistletoe in regions where it is in great abundance 

 may be considered quite as great a factor in initiating the ravages 

 of ftmgi and insects as fire. Many forest fires resiilt from light- 

 ning, striking trees which have a large amount of dry wood either 

 of the lower branches or at the top. One of the most common 

 effects of mistletoe is to cause the top of the tree to die. We have 

 here another direct relation of mistletoe to forest fires. The 

 accumulation of fallen mistletoe brooms about the bases of larches 

 often insures the death of the tree in case of ground fires even if the 

 fire does not extend to the dry dead brooms still attached to the 

 tree. The formation of burls and "cat faces" by mistletoe on the 

 main trunk may cause extensive windfalls in times of high winds, 

 thus littering the forest floor with a highly inflammable material, 

 At certain stages in their formation, these burls exude large quan- 

 tities of pitch which is a factor in holding the fire at one point 

 on the trunk, resulting in deep wounds. 



The false mistletoes (Razoumofskya) are of much greater im- 

 portance in the West than in the East. Only one species is 

 known to occur on Eastern conifers and is of importance in but 

 few regions. This species so far as known does not occur in the 

 West. In great contrast to this, practically every Western conifer 

 is attacked by some one of these parasites. Space will not allow 

 of going into detail, but the timber trees most seriously affected 

 are the Lodgepole pine. Yellow pine, Douglas fir, larch, and hem- 

 lock. The reason why these parasites have not received greater 

 attention from the practical forester is probably due to the fact 

 that the work of wood-destroying fungi is more directly associated 

 with the destruction of the merchantable parts of the tree, their 

 great abundance, and also because of the conspicuous nature of 

 their fructification. Some species of the false mistletoes are very 



