Depending upon the amount of stocking present, this reduction in numbers may be somewhat 

 beneficial to the stand; or, in sparsely stocked stands the removal of a few trees may 

 seriously hamper natural restocking. Furthermore, the mechanical injury of these under- 

 story trees makes them more subject to heart rots and other fungus infections by pro- 

 viding the avenue of entrance in the scarred boles. This type of damage may be rather 

 difficult to predict. The effect of damage and subsequent fungus attack may not mani- 

 fest itself until many years after the epidemic. 



Gibson also pointed out that direct wmdthrow of residual green trees in heavily 

 attacked stands results when these trees lose the protection of trees killed by the 

 beet les . 



V. • 

 Increased fire hazard resulting from tree killing and windthrow has been pointed 

 out by many writers including Flint (1924) and Gibson.^ 'Flint estimated that the 

 amount of labor necessary to control a fire in areas having large accumulations of 

 beetle-killed trees may be doubled. There is no question but that the cost of fire 

 suppression m beetle-decimated stands will be considerably higher for two reasons: 

 (1) the physical job of removing the extra load of windfalls requires more labor and 

 machine time for operations such as fireline construction; and (2) the large volume of 

 dead material, either standing or on the ground, creates a much hotter fire than would 

 normally occur resulting in a more difficult suppression job. The hotter burn also may 

 have more far-reaching effects on soils than more normal cooler fires. More research 

 is required to increase our knowledge of the effect of such hot fires on soils. 



MANAGEMENT ALTERNATIVES 



The nearly constant mountain pine beetle pressure being exerted in the Inter- 

 mountain lodgepole pine forests poses perplexing management problems. Among them are 

 such problems as successful beetle control, acceptable risk from stand decimating 

 forces, and long term management goals and plans to cope with the beetle. 



BEETLE CONTROL 



Expensive stopgap measures such as direct control involving the spraying of stand- 

 ing or felled trees with penetrating toxic chemicals provide only a holding action 

 until the potentially susceptible trees can be disposed of in some other way.^ A great 

 deal of mortality results despite any immediate success of the control measures. The 

 unpredictability of these control measures and the relative certainty of reinfestation 

 of the stand later on leaves the manager with relatively little choice of action. He 

 must cut and regenerate the lodgepole pine stand as soon as possible if he wishes to 

 avert further loss, or risk the loss of the stand to further depletion by beetle 

 activity and ultimate displacement by other species which are sometimes considered 

 less desirable. 



One of the critical needs is to develop more effective and predictable beetle 

 control measures, especially for use in combination with si Ivi cultural practices. 



Pheromones (chemicals produced and used for communication by insects] offer, at 

 this time, some remote promise of control through population manipulation. The 

 pheromones of several species of bark beetles have been identified (Renwick 1967; 

 Silverstein et al . 1966a, 1966b, 1968). More recently, research sponsored by the 



^Memorandum dated 10/11/68 from Floyd Iverson, Regional Forester, Region 4, to 

 Chief of Forest Service, reporting on the R-4 field survey. Report on file at Inter- 

 mountain Forest and Range Experiment Station, Ogden, Utah. 



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