INSECT INJURIES TO HARDWOOD FOREST TREES. 



By A. D. HOPKINS. 

 /// ( 'hurt/i' of Forext Inwcf Investigations^ JHrlxion of Entomology. 



EXTENT OF DAMAGE DETERMINED HY SPECIAL INVESTIGATIONS. 



Within recent years the writer 1ms conducted investigations in the 

 principal hardwood forests of the country for the purpose of deter- 

 mining the extent and character of damage caused by insects, and 

 especially that which results in direct losses to the owners, manufac- 

 turers, and consumers of hardwood forest products. This resulted in 

 finding that oaks, chestnut, hickories, maples, birches, walnuts, cherry, 

 tulip or yellow 7 poplar, gums, and others of our principal hardwood, 

 or broad-leaved, timber trees are damaged to a far greater extent than 

 U realized by the casual observer. A large percentage of the hard- 

 wood timber in nearly all of the States east of the Rocky Mountains 

 is affected, and the average annual losses from this source we would 

 estimate at between 15 and 20 million dollars. There is not only a 

 direct loss to owners of forests, and manufacturers and consumers 

 of forest products, but the continued depredation is contributing to 

 the rapid depletion of the available hardwood timber supply of the 

 country. 



THE CHARACTER OF INSECT INJURIES TO LIVING FOREST TREES. 



The character of insect injuries to living forest trees may be discussed 

 under two distinct heads: 



(1) Injuries which cause the death of the trees. 



(2) Injuries to the wood which do not materially affect the vitality- 

 of the trees, but cause serious defects in the parts which furnish com- 

 mercial products'. 



There is also great loss from insect injuries to felled timber, saw 

 logs, round and square timber, lumber, and other crude products, but 

 the limited space allotted here will not permit a discussion of this 

 phase of the subject. 



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