166 PROTECTION AGAINST INSECTS. 



that there may not be extensive tracts of even-aged woods. 

 Several cutting-series should be established, by the use of 

 severance fellings, if necessary. This gives a choice of the felling- 

 area for any particular year, and contiguous compartments 

 are not cut in successive years. Fellings should be arranged 

 against the prevailing winds, in order to avoid extensive 

 windfalls and the consequent danger from bark-beetles. 



(viii) Stools of felled trees should be extracted or carefully 

 earthed over, especially in coniferous forests, as many highly 

 injurious species of insects {Hijlohias ahietis, and several 

 species of Hi/lastcs) lay their eggs in stumps and roots. 



(ix) Summer-felling in coniferous forests, together with 

 careful removal of the bark. Wherever winter-felling is advis- 

 able for other reasons, some of the stems should be left lying 

 as traps and barked in May, after the bark-beetles have laid 

 their eggs in them. Wood felled during winter is now usually 

 partially barked in strips, if it cannot be removed before the 

 breeding season of the bark-beetles. If, however, these beetles 

 do not find wood with the bark on lying in the forest they will 

 lay their eggs in the bark of standing trees, while the cost of 

 partial barking is considerable, and it is easier to destroy the 

 larvae in fallen timber than in standing trees. 



(x) The forests must be kept clean, the fellings rapidly and 

 thoroughly cleared, and material from thinnings carted away 

 without unnecessary delay. 



Further preventive measures against many species of insects 

 are : turning-in swine for " pannage," the employment of 

 caterpillar-trenches, wood-traps, grease rings, etc. As, how- 

 ever, these measures are remedial, as well as preventive, they 

 will be discussed further on. 



(xi) Rewards should be offered to the Protective Staff for 

 discovering injurious insects and for special zeal shown in 

 carrying out the rules for destroying them. 



h. l^iolection of I/isfrUrorou.s A)u)NaJs. 



Only those animals should be protected which do more 

 good by the destruction of insects than harm in other 

 ways. 



